Processing of copper ore excavation crushing. Ore crushing - jaw cone hammer and roller crushers. Complex for processing copper ore Crushing and sorting complex for processing copper ore
Copper ore processing plant in mining, beneficiation, smelting, refining and casting
Crushing and screening complex for processing copper ore
The copper ore processing plant is a crushing plant specially designed for crushing copper ore. When the copper ore comes out of the ground, it is loaded into a 300-ton truck to transport the crusher. Complete copper crushing plant includes jaw crushers like main crusher, impact crusher and cone crusher. After being crushed, the copper ore must be screened to size by screening machine and spread the graded ore to a series of conveyors, to be transported to the mill for further processing.
Complex for processing copper ore
The process for extracting copper from copper ore varies depending on the type of ore and the required purity of the final product. Each process consists of several steps in which unwanted materials are physically or chemically removed, and the concentration of copper is gradually increased.
First, the copper ore from the open pit is crushed, loaded and transported to the primary crusher. Then the ore is crushed and screened, with fine sulfide ore (< 0.5 мм) собирается пенной флотации клеток для восстановления меди. Крупные частицы руды идет в кучного выщелачивания, где меди подвергается разбавленного раствора серной кислоты, чтобы растворить медь.
The alkaline solution containing dissolved copper is then subjected to a process called solvent extraction (SX). The SX process concentrates and purifies the copper leaching solution, so copper can be recovered at high electrical current efficiency by cell electrolysis. It does this by adding a chemical reagent to the SX tanks that selectively binds to and extracts the copper, easily separating from the copper, recovering as much of the reagent as possible for reuse.
The concentrated copper solution is dissolved in sulfuric acid and sent to electrolytic cells to recover copper plates. From copper cathodes, it is fabricated into wires, appliances, etc.
SBM can offer types of crusher, screening and grinding machine, copper ore flotation plant, processing plant in USA, Zambia, Canada, Australia, Kenya, South Africa, Papua New Guinea and Congo.
Copper ore has a different composition, which affects its quality characteristics and determines the choice of the method of enrichment of the feedstock. The composition of the rock can be dominated by sulfides, oxidized copper, and a mixed amount of components. At the same time, in relation to ore mined in the Russian Federation, the flotation enrichment method is used.
Processing of sulfide copper ore of disseminated and continuous type, which contains no more than a quarter of oxidized copper, is carried out in Russia at processing plants:
- Balkhash;
- Dzhezkazganskaya;
- Sredneuralskaya;
- Krasnouralskaya.
The raw material processing technology is selected according to the type of raw material.
Work with disseminated ores involves the extraction of sulfides from the rock and their transfer to depleted concentrates using chemical compounds: blowing agents, hydrocarbons and xanthate. Rather coarse grinding of the rock is used primarily. After processing, the poor concentrate and middlings undergo an additional process of grinding and cleaning. During processing, copper is released from intergrowths with pyrite, quartz and other minerals.
The homogeneity of the porphyrated ore supplied for processing ensures the possibility of its flotation at large concentrating enterprises. A high level of productivity makes it possible to achieve a reduction in the cost of the enrichment procedure, as well as to accept ore with a low copper content (up to 0.5%) for processing.
Schemes of the flotation process
The flotation process itself is built according to several basic schemes, each of which differs both in the level of complexity and cost. The simplest (cheapest) scheme provides for a transition to an open ore processing cycle (at the 3rd stage of crushing), ore grinding within one stage, as well as a subsequent regrinding procedure with a result of 0.074 mm.
During the flotation process, the pyrite contained in the ore is subjected to depression, leaving a sufficient level of sulfur in the concentrates, which is necessary for the subsequent production of slag (matte). For depression, a solution of lime or cyanide is used.
Solid sulfide ores (cuprous pyrites) are distinguished by the presence of a significant amount of copper-bearing minerals (sulfates) and pyrite. Copper sulfides form thin films (covellite) on pyrite, while, due to the complexity of the chemical composition, the floatability of such ore is somewhat reduced. An efficient beneficiation process requires careful grinding of the rock to facilitate the release of copper sulphides. It is noteworthy that in a number of cases, thorough grinding is devoid of economic feasibility. We are talking about situations where the pyrite concentrate subjected to the roasting process is used in blast-furnace smelting in order to extract precious metals.
Flotation is carried out when creating an alkaline medium of high concentration. In the process, the following proportions are used:
- lime;
- xanthate;
- fleetoil.
The procedure is quite energy intensive (up to 35 kWh/t), which increases production costs.
The process of grinding ore is also complex. As part of its implementation, multi-stage and multi-stage processing of the source material is provided.
Enrichment of intermediate type ore
The processing of ore with a sulfide content of up to 50% is similar in technology to the enrichment of solid sulfide ore. The difference is only the degree of its grinding. The material of a coarser fraction is accepted for processing. In addition, the separation of pyrite does not require the preparation of a medium with such a high alkali content.
Collective flotation followed by selective processing is practiced at the Pyshminskaya concentrator. The technology makes it possible to use 0.6% ore to obtain 27% copper concentrate with subsequent recovery of over 91% copper. Works are carried out in an alkaline environment with different levels of intensity at each stage. The processing scheme allows to reduce the consumption of reagents.
Technology of combined enrichment methods
It is worth noting that ore with a low content of impurities of clay and iron hydroxide lends itself better to the enrichment process. The flotation method makes it possible to extract up to 85% of copper from it. If we talk about refractory ores, then the use of more expensive combined enrichment methods, for example, the technology of V. Mostovich, becomes more effective. Its application is relevant for the Russian industry, since the amount of refractory ore is a significant part of the total production of copper-bearing ore.
The technological process involves the crushing of raw materials (fraction size up to 6 mm) followed by immersion of the material in a solution of sulfuric acid. This allows sand and sludge to be separated, and free copper to go into solution. The sand is washed, leached, passed through a classifier, crushed and floated. The copper solution is combined with the sludge and then subjected to leaching, cementation and flotation.
In the work according to the Mostovich method, sulfuric acid is used, as well as precipitating components. The use of technology turns out to be more costly in comparison with operation according to the standard flotation scheme.
The use of an alternative scheme of Mostovich, which provides for the recovery of copper from oxide with flotation after crushing of heat-treated ore, allows to somewhat reduce costs. To reduce the cost of technology allows the use of inexpensive fuel.
Flotation of copper-zinc ore
The process of flotation of copper-zinc ore is labor intensive. The difficulties are explained by the chemical reactions that occur with multicomponent raw materials. If the situation is somewhat simpler with primary sulfide copper-zinc ore, then the situation when exchange reactions began with the ore already in the deposit itself can complicate the enrichment process. Conducting selective flotation, when dissolved copper and films of cavellin are present in the ore, may become impossible. Most often, such a picture occurs with ore mined from the upper horizons.
In the beneficiation of the Ural ore, which is rather poor in terms of copper and zinc, the technology of both selective and collective flotation is effectively used. At the same time, the method of combined ore processing and the scheme of collective selective enrichment are increasingly used at the leading enterprises of the industry.
The owners of the patent RU 2418872:
The invention relates to copper metallurgy, and in particular to methods for processing mixed (sulfide-oxidized) copper ores, as well as industrial products, tailings and slags containing oxidized and sulfide copper minerals. The method for processing mixed copper ores includes crushing and grinding the ore. Then, crushed ore is leached with a solution of sulfuric acid with a concentration of 10-40 g/dm 3 with stirring, solid phase content 10-70%, duration 10-60 minutes. After leaching, dehydration and washing of the ore leaching cake is carried out. Then the liquid phase of ore leaching is combined with washing water and the combined copper-containing solution is freed from solid suspensions. Copper is recovered from the copper-containing solution to obtain cathode copper. From the leaching cake, copper minerals are flotation at a pH value of 2.0-6.0 to obtain a flotation concentrate. The technical result consists in increasing the extraction of copper from ore into marketable products, reducing the consumption of reagents for flotation, increasing the flotation speed, and reducing the cost of grinding. 7 w.p. f-ly, 1 ill., 1 tab.
The invention relates to copper metallurgy, and in particular to methods for processing mixed (sulfide-oxidized) copper ores, as well as intermediate products, tailings and slags containing oxidized and sulfide copper minerals, and can also be used for processing mineral products of other non-ferrous metals.
Processing of copper ores is carried out using leaching or flotation enrichment, as well as using combined technologies. The world practice of processing copper ores shows that the degree of their oxidation is the main factor influencing the choice of technological schemes and determining the technological and technical and economic indicators of ore processing.
For the processing of mixed ores, technological schemes have been developed and applied that differ in the methods used for extracting metal from ore, methods for extracting metal from leaching solutions, a sequence of extraction methods, methods for separating solid and liquid phases, organizing phase flows and layout rules. The set and sequence of methods in the technological scheme is determined in each specific case and depends, first of all, on the mineral forms of copper in the ore, the copper content in the ore, the composition and nature of the host minerals and ore rocks.
A known method of extracting copper, which consists in dry crushing of ore to a particle size of 2, 4, 6 mm, leaching with classification, subsequent flotation of the granular part of the ore and sedimentation of the slurry fraction of the copper concentrate with sponge iron from the slurry part of the ore (AS USSR N 45572, B03B 7/00, 31.01.36).
The disadvantage of this method is the low extraction of copper and the quality of the copper product, to improve which requires additional operations.
A known method for producing metals, which consists in grinding the source material to a fraction size exceeding the size of the fractions required for flotation, leaching with sulfuric acid in the presence of iron belongings, followed by the direction of solid residues for flotation of copper deposited on the iron belongings (DE 2602849 B1, C22B 3/02 , 30.12.80).
A similar method is known for processing refractory oxidized copper ores by Professor Mostovich (Mitrofanov S.I. et al. Combined processes for processing non-ferrous metal ores, M., Nedra, 1984, p. 50), which consists in leaching oxidized copper minerals with acid, cementing copper from solution iron powder, flotation of cement copper from an acidic solution to obtain a copper concentrate. The method is applied for processing refractory oxidized ores of the Kalmakir deposit at the Almalyk mining and smelting plant.
The disadvantages of these methods is the high cost of implementation due to the use of iron belongings, which reacts with acid, while increasing the consumption of both sulfuric acid and iron belongings; low recovery of copper by carburizing with iron goods and flotation of cement particles. The method is not applicable for the processing of mixed ores and the flotation separation of sulfide copper minerals.
The closest to the claimed method in terms of technical essence is a method for processing sulfide-oxidized copper ores (RF Patent No. 2.0 hours of crushed ore with a solution of sulfuric acid with a concentration of 10-40 g / dm 3 with stirring, solids content of 50-70%, dehydration and washing of the leaching cake, grinding it, combining the liquid phase of ore leaching with washing water of the ore leaching cake, release from solid suspensions and extraction of copper from a copper-containing solution to obtain cathode copper and flotation of copper minerals from crushed leaching cake in an alkaline medium with a reagent-regulator to obtain a flotation concentrate.
The disadvantages of this method are the high consumption of reagents-regulators of the environment for flotation in an alkaline medium, insufficiently high extraction of copper during flotation due to oxide copper minerals coming after leaching of large particles, screening of copper minerals by the reagent-regulator of the environment, high consumption of collectors for flotation.
The invention achieves a technical result, which consists in increasing the extraction of copper from ore into marketable products, reducing the consumption of reagents for flotation, increasing the flotation speed, and reducing the cost of grinding.
The specified technical result is achieved by a method for processing mixed copper ores, including crushing and grinding of ore, leaching of crushed ore with a solution of sulfuric acid with a concentration of 10-40 g/dm 3 with stirring, a solids content of 10-70%, a duration of 10-60 minutes, dehydration and washing ore leaching cake, combining the ore leaching liquid phase with the leaching cake wash water, releasing the combined copper-bearing solution from solid suspensions, extracting copper from the copper-bearing solution to obtain cathode copper and flotation of copper minerals from the leaching cake at a pH value of 2.0-6.0 s receiving flotation concentrate.
Particular cases of using the invention are characterized by the fact that the grinding of the ore is carried out to a particle size of 50-100% of the class minus 0.1 mm to 50-70% of the class minus 0.074 mm.
Also, the washing of the leaching cake is carried out simultaneously with its dehydration by filtration.
In addition, the combined copper-containing solution is freed from solid suspensions by clarification.
Preferably, the flotation is carried out using several of the following collectors: xanthate, sodium diethyldithiocarbamate, sodium dithiophosphate, aeroflot, pine oil.
Also, the extraction of copper from a copper-containing solution is carried out by the method of liquid extraction and electrolysis.
In addition, the extraction raffinate resulting from liquid extraction is used for ore leaching and for washing the leach cake.
Also, the spent electrolyte formed during electrolysis is used for ore leaching and for washing the leaching cake.
The speed and efficiency of leaching copper minerals from ore depends on the size of the ore particles: the smaller the particle size, the more available the minerals for leaching, dissolve faster and to a greater extent. For leaching, ore grinding is carried out to a size slightly larger than for flotation enrichment, i.e. from 50-100% of the class minus 0.1 mm, to 50-70% of the class minus 0.074 mm, since the particle size decreases after leaching. The content of the size class during ore grinding depends on the mineral composition of the ore, in particular on the degree of oxidation of copper minerals.
After the leaching of the ore, copper minerals are flotation, the efficiency of which also depends on the size of the particles - large particles are poorly floated and the smallest particles - sludge. When crushed ore is leached, sludge particles are completely leached, and the largest ones are reduced in size, as a result, the particle size without additional grinding corresponds to the material size required for efficient flotation of mineral particles.
Stirring during the leaching of crushed ore provides an increase in the rate of mass-transfer physical and chemical processes, while increasing the extraction of copper into solution and reducing the duration of the process.
The leaching of crushed ore is effectively carried out at a solids content of 10 to 70%. An increase in the ore content during leaching up to 70% makes it possible to increase the productivity of the process, the concentration of sulfuric acid, creates conditions for the friction of particles between themselves and their grinding, and also makes it possible to reduce the volume of leaching apparatuses. Leaching at a high ore content results in a high concentration of copper in solution, which reduces the driving force of mineral dissolution and the rate of leaching compared to leaching at a low solids content.
Leaching of ore with a size of minus 0.1-0.074 mm with a solution of sulfuric acid with a concentration of 10-40 g/dm 3 for 10-60 minutes makes it possible to obtain a high extraction of copper from oxidized minerals and secondary copper sulfides. The rate of dissolution of oxidized copper minerals in a solution of sulfuric acid with a concentration of 10-40 g/dm 3 is high. After leaching crushed mixed copper ore for 5-10 minutes, the content of difficult-to-float oxidized minerals in the ore is significantly reduced and is less than 30%, thus it passes into the sulfide technological grade. The recovery of copper minerals remaining in the leaching cake can be carried out in the sulfide minerals flotation mode. As a result of sulfuric acid leaching of crushed mixed copper ore, oxidized copper minerals and up to 60% secondary copper sulfides are almost completely dissolved. The content of copper in the leaching cake and the load on the flotation enrichment of the leaching cake are significantly reduced and, accordingly, the consumption of flotation reagents - collectors is also reduced.
Preliminary sulfuric acid treatment of sulfide-oxidized copper ores allows not only to remove oxidized copper minerals that are difficult to float, but also to clean the surface of sulfide minerals from iron oxides and hydroxides, to change the composition of the surface layer in such a way that the floatability of copper minerals increases. Using X-ray photoelectron spectroscopy, it was found that as a result of sulfuric acid treatment of copper sulfides, the elemental and phase composition of the surface of minerals changes, affecting their flotation behavior - the sulfur content increases by 1.44 times, copper by 4 times, and the iron content decreases by 1.6 times. The ratio of sulfur phases on the surface after sulfuric acid treatment of secondary copper sulfides changes significantly: the proportion of elemental sulfur increases from 10 to 24% of the total sulfur, the proportion of sulfate sulfur - from 14 to 25% (see drawing: S2p spectra of sulfur (type of hybridization of electron orbitals, characterized by a certain binding energy) of the surface of copper sulfides, A - without treatment, B - after sulfuric acid treatment, 1 and 2 - sulfur in sulfides, 3 - elemental sulfur, 4, 5 - sulfur in sulfates). Taking into account the increase in total sulfur on the surface of minerals, the content of elemental sulfur increases by 3.5 times, sulfate sulfur by 2.6 times. Studies of the surface composition also show that as a result of sulfuric acid treatment, the content of iron oxide Fe 2 O 3 on the surface decreases and the content of iron sulfate increases, the content of copper sulfide Cu 2 S decreases and the content of copper sulfate increases.
Thus, when crushed mixed copper ore is leached, the composition of the surface of copper sulfide minerals changes, which affects their flotation qualities, in particular:
The content of elemental sulfur on the surface of copper sulfide minerals, which has hydrophobic properties, increases, which makes it possible to reduce the consumption of collectors for flotation of copper sulfide minerals;
The surface of copper minerals is cleaned from iron oxides and hydroxides, which shield the surface of minerals, therefore, the interaction of minerals with the collector is reduced.
For further processing of the leach products, the leach cake is dehydrated, which can be combined with washing the leach cake, for example, on belt filters, from the copper contained in the moisture of the cake. A variety of filtration equipment, such as filter centrifuges and belt vacuum filters, as well as settling centrifuges, etc. are used for dewatering and washing the ore leach cake.
The ore leaching solution and the ore leaching cake washings to extract the copper contained in them are combined and freed from solid suspensions, since they worsen the conditions for copper extraction and reduce the quality of the obtained cathode copper, especially when using the liquid extraction process with an organic extractant. Removal of suspensions can be carried out in the simplest way - clarification, as well as additional filtration.
Copper is extracted from the clarified copper-bearing ore leaching solution and washing the leaching cake to obtain cathode copper. A modern method for extracting copper from solutions is the method of liquid extraction with an organic cation-exchange extractant. Using this method allows you to selectively extract and concentrate copper in solution. After the stripping of copper from the organic extractant, electroextraction is performed to obtain cathode copper.
During liquid extraction of copper from sulfuric acid solutions with an organic extractant, an extraction raffinate is formed, which contains 30-50 g/dm 3 of sulfuric acid and 2.0-5.0 g/dm 3 of copper. To reduce acid consumption for leaching and copper losses, as well as rational water circulation in the technological scheme, the extraction raffinate is used for leaching and for washing the leaching cake. At the same time, the concentration of sulfuric acid in the residual moisture of the leaching cake increases.
During the electrolysis of copper from impurities, such as iron, purified from impurities, and copper-containing solutions concentrated during liquid extraction, a spent electrolyte is formed, with a concentration of 150-180 g/dm 3 of sulfuric acid and 25-40 g/dm 3 of copper. As well as the extraction raffinate, the use of the spent electrolyte for leaching and washing the leaching cake makes it possible to reduce the consumption of fresh acid for leaching, the loss of copper, and rationally use the aqueous phase in the technological scheme. When using the spent electrolyte for washing, the concentration of sulfuric acid in the residual moisture of the leaching cake increases.
Grinding after leaching for the flotation separation of copper minerals is not required, since in the process of leaching the particles decrease in size and the size of the leaching cake corresponds to the flotation 60-95% of the class minus 0.074 mm.
In Russia, for the flotation enrichment of copper minerals, an alkaline medium is used, which is determined by the predominant use as collectors of xanthates, which are known to decompose under acidic conditions, and, in some cases, by the need for pyrite depression. To regulate the environment in alkaline flotation in industry, lime milk is most often used as the cheapest reagent, which makes it possible to increase the pH to strongly alkaline values. Calcium entering the flotation pulp with milk of lime shields the surface of minerals to some extent, which reduces their floatability, increases the yield of enrichment products and reduces their quality.
When processing mixed copper ores of the Udokan deposit, the crushed ore after sulfuric acid treatment is washed from copper ions with acid extraction raffinate, spent electrolyte and water. As a result, the leaching cake moisture has an acidic environment. Subsequent flotation of copper minerals under alkaline conditions requires high water washing and lime neutralization, which increases processing costs. Therefore, it is advisable to carry out the flotation enrichment of sulfide copper minerals after sulfuric acid leaching in an acidic environment, at a pH value of 2.0-6.0, to obtain a copper concentrate and tailings.
Studies have shown that in the main flotation of copper minerals from sulfuric acid leaching cakes, with a decrease in pH, the copper content in the concentrate of the main flotation gradually increases from 5.44% (pH 9) to 10.7% (pH 2) with a decrease in yield from 21% to 10.71% and a reduction in recovery from 92% to 85% (Table 1).
| Table 1 | |||||
| An example of enrichment of cakes of sulfuric acid leaching of copper ore from the Udokan deposit at various pH values | |||||
| pH | Products | Output | Copper content, % | Extraction of copper, % | |
| G | % | ||||
| 2 | Main flotation concentrate | 19,44 | 10,71 | 10,77 | 85,07 |
| 38,88 | 21,42 | 0,66 | 10,43 | ||
| Tails | 123,18 | 67,87 | 0.09 | 4,5 | |
| Source ore | 181,50 | 100,00 | 1,356 | 100,00 | |
| 4 | Main flotation concentrate | 24,50 | 12,93 | 8,90 | 87,48 |
| Control flotation concentrate | 34,80 | 18,36 | 0,56 | 7,82 | |
| Tails | 130,20 | 68,71 | 0,09 | 4,70 | |
| Source ore | 189,50 | 100,00 | 1,32 | 100,00 | |
| 5 | Main flotation concentrate | 32,20 | 16,51 | 8,10 | 92,25 |
| Control flotation concentrate | 17,70 | 9,08 | 0,50 | 3,13 | |
| Tails | 145,10 | 74,41 | 0,09 | 4,62 | |
| Source ore | 195,00 | 100,00 | 1,45 | 100,00 | |
| 6 | Main flotation concentrate | 36,70 | 18,82 | 7,12 | 92,89 |
| Control flotation concentrate | 16,00 | 8,21 | 0,45 | 2,56 | |
| Tails | 142,30 | 72,97 | 0,09 | 4,55 | |
| Source ore | 195,00 | 100,00 | 1,44 | 100,00 | |
| 7 | Main flotation concentrate | 35,80 | 19,02 | 6,80 | 92,40 |
| Control flotation concentrate | 15,40 | 8,18 | 0,41 | 2,40 | |
| Tails | 137,00 | 72,79 | 0,10 | 5,20 | |
| Source ore | 188,20 | 100,00 | 1,40 | 100,00 | |
| 8 | Main flotation concentrate | 37,60 | 19,17 | 6,44 | 92,39 |
| Control flotation concentrate | 14,60 | 7,45 | 0,38 | 2,12 | |
| Tails | 143,90 | 73,38 | 0,10 | 5,49 | |
| Source ore | 196,10 | 100,00 | 1,34 | 100,00 | |
| 9 | Main flotation concentrate | 42,70 | 21,46 | 5,44 | 92,26 |
| Control flotation concentrate | 14,30 | 7,19 | 0,37 | 2,10 | |
| Tails | 142,00 | 71,36 | 0,10 | 5,64 | |
| Source ore | 199,00 | 100,00 | 1,27 | 100,00 |
In control flotation, the lower the pH value, the higher the copper content in the concentrate, the yield and recovery are greater. The output of the control flotation concentrate in an acid medium is large (18.36%), with an increase in the pH value, the output of this concentrate decreases to 7%. The extraction of copper into the total concentrate of the main and control flotation over the entire range of the studied pH values is almost the same and is about 95%. Flotation recovery at lower pH is higher compared to copper recovery at higher pH due to higher yield to concentrates under acidic flotation conditions.
After sulfuric acid treatment of the ore, the flotation rate of sulfide copper minerals increases, the time of the main and control flotation is only 5 minutes, in contrast to the ore flotation time of -15-20 minutes. The flotation rate of copper sulfides is much higher than the rate of decomposition of xanthate at low pH values. The best results of flotation enrichment are achieved by using several collectors from a range of potassium butyl xanthate, sodium dithiophosphate, sodium diethyldithiocarbamate (DEDTC), aeroflot, pine oil.
According to the residual concentration of xanthate after interaction with copper sulfides, it was experimentally determined that on the surface of minerals subjected to sulfuric acid treatment, xanthate is sorbed 1.8–2.6 times less than on the surface without treatment. This experimental fact is consistent with the data of an increase in the content of elemental sulfur on the surface of copper sulfides after sulfuric acid treatment, which, as is known, increases its hydrophobicity. Studies of froth flotation of secondary copper sulfides showed (the abstract of the dissertation “Physical and chemical foundations of the combined technology for processing copper ores of the Udokan deposit” by Krylova L.N.) that sulfuric acid treatment leads to an increase in the extraction of copper into concentrate by 7.2÷10.1% , the output of the solid phase by 3.3÷5.5% and the copper content in the concentrate by 0.9÷3.7%.
The invention is illustrated by examples of the implementation of the method:
The mixed copper ore of the Udokan deposit, containing 2.1% copper, of which 46.2% is in oxidized copper minerals, was crushed, ground to a fineness of 90% of the class minus 0.1 mm, leached in a vat with stirring at a solids content of 20% , the initial concentration of sulfuric acid 20 g/DM 3 maintaining the concentration of sulfuric acid at 10 g/DM 3 for 30 minutes. Extraction raffinate and spent electrolyte were used for leaching. The leaching cake was dehydrated on a vacuum filter and washed on a belt filter with extraction raffinate and water.
Flotation enrichment of the sulfuric acid leaching cake was carried out at pH 5.0 using potassium butyl xanthate and sodium diethyldithiocarbamate (DEDTC) as collectors in an amount 16% less than for flotation of crushed copper ore leaching cake with a particle size of 1-4 mm. As a result of flotation enrichment, the extraction of copper into the total sulfide copper concentrate was 95.1%. Lime was not used for flotation enrichment, which is consumed in the amount of up to 1200 g/t of ore during alkaline leaching cake flotation.
The liquid phase of the leach and washings were combined and clarified. Extraction of copper from solutions was carried out with a solution of an organic extractant LIX 984N, cathode copper was obtained by electrolysis of copper from a copper-containing acid solution. Through extraction of copper from the ore by the method amounted to 91.4%.
The copper ore of the Chineisk deposit, containing 1.4% copper, in which 54.5% is in oxidized copper minerals, was crushed and ground to a fineness of 50% of the class minus 0.074 mm, leached in a vat with stirring at a solids content of 60%, the initial concentration sulfuric acid 40 g/dm 3 using spent electrolyte. The leaching pulp was dehydrated on a vacuum filter and washed on a belt filter, first with spent electrolyte and extraction raffinate, then with water. Leaching cake without regrinding was enriched by flotation at pH 3.0 using xanthate and aeroflot at a flow rate (total consumption of 200 g/t) lower than in ore flotation (collector flow rate of 350-400 g/t). Extraction of copper in sulfide copper concentrate was 94.6%.
The leach liquid phase and the leach cake washes were combined and clarified. Extraction of copper from solutions was carried out with a solution of organic extractant LIX, cathode copper was obtained by electroextraction of copper from a copper-containing acid solution. Through extraction of copper from ore into marketable products amounted to 90.3%.
1. A method for processing mixed copper ores, including crushing and grinding of ore, leaching of crushed ore with a solution of sulfuric acid with a concentration of 10-40 g / dm 3 with stirring, a solids content of 10-70%, a duration of 10-60 minutes, dehydration and washing of the cake ore leaching, combining the liquid phase of the ore leaching with the washing water of the leach cake, the release of the combined copper-containing solution from solid suspensions, the extraction of copper from the copper-containing solution to obtain cathode copper and the flotation of copper minerals from the leaching cake at a pH value of 2.0-6.0 to obtain flotation concentrate.
2. The method according to claim 1, in which the grinding of the ore is carried out to a fineness ranging from 50-100% of the class minus 0.1 mm to 50-70% of the class minus 0.074 mm.
3. The method according to claim 1, in which the washing of the leach cake is carried out simultaneously with its dehydration by filtration.
4. The method according to claim 1, wherein the combined copper-containing solution is freed from solid suspensions by clarification.
5. The process of claim 1 wherein the flotation is carried out using several of the following collectors: xanthate, sodium diethyldithiocarbamate, sodium dithiophosphate, aeroflot, pine oil.
6. The method according to claim 1, in which the extraction of copper from a copper-containing solution is carried out by the method of liquid extraction and electrolysis.
7. The process of claim 6 wherein the extraction raffinate from the liquid extraction is used to leach the ore and to wash the leach cake.
8. The method of claim 6 wherein the spent electrolyte from the electrolysis is used to leach the ore and to wash the leach cake.
The invention relates to copper metallurgy, and in particular to methods for processing mixed copper ores, as well as intermediate products, tailings and slags containing oxidized and sulfide copper minerals
The mined mineral in most cases is a mixture of pieces of various sizes, in which the minerals are closely intergrown, forming a monolithic mass. The size of the ore depends on the type of mining and, in particular, on the method of blasting. During open mining, the largest pieces are 1-1.5 m in diameter, while underground mining is somewhat smaller.To separate the minerals from each other, the ore must be crushed and ground.
To free minerals from mutual intergrowth, in most cases, fine grinding is required, for example, up to -0.2 mm and finer.
The ratio of the diameter of the largest pieces of ore (D) to the diameter of the crushed product (d) is called the degree of crushing or the degree of grinding (K):
For example, at D = 1500 mm and d = 0.2 mm.
K \u003d 1500 ÷ 0.2 \u003d 7500.
Crushing and grinding are usually carried out in several stages. At each stage, crushers and mills of various types are used, as shown in table. 68 and in fig. one.
Crushing and grinding can be dry and wet.
Depending on the final practicable degree of grinding in each stage, the number of stages is chosen. If the required degree of grinding is K, and in individual stages - k1, k2, k3 ..., then
The overall degree of grinding is determined by the size of the original ore and the size of the final product.
Crushing is cheaper, the finer the mined ore. The larger the volume of the excavator bucket for mining, the larger the mined ore, which means that crushing units should be used in large sizes, which is not economically profitable.
The degree of crushing is chosen such that the cost of equipment and operating costs are the lowest. The size of the loading gap should be 10-20% larger for jaw crushers than the transverse size of the largest pieces of ore, for conical and cone crushers it should be equal to a piece of ore or slightly larger. The calculation of the performance of the selected crusher is based on the width of the discharge slot, taking into account the fact that the crushed product always contains pieces of ore two to three times larger than the selected slot. To obtain a product with a particle size of 20 mm, you need to choose a cone crusher with a discharge gap of 8-10 mm. With a small assumption, it can be assumed that the performance of crushers is directly proportional to the width of the discharge gap.
Crushers for small factories are selected based on one shift, for factories of medium productivity - in two, for large factories, when several crushers are installed at the stages of medium and fine crushing - in three shifts (six hours each).
If, with a minimum width of the mouth corresponding to the size of the ore pieces, the jaw crusher can provide the required productivity in one shift, and the conical crusher will be underloaded, then a jaw crusher is chosen. If the cone crusher with a loading gap equal to the size of the largest pieces of ore is provided with work for one shift, then preference should be given to the cone crusher.
In the mining industry, rolls are rarely installed; they are replaced by short-cone crushers. For crushing soft, for example, manganese ores, as well as coals, toothed rolls are used.
In recent years, impact crushers have become relatively widespread, the main advantage of which is a large degree of grinding (up to 30) and selectivity of crushing due to splitting pieces of ore along the planes of intergrowth of minerals and along the weakest points. In table. 69 shows comparative data of impact and jaw crushers.
Impact crushers are installed for the preparation of material in metallurgical shops (crushing of limestone, mercury ores for the roasting process, etc.). Mekhanobrom tested a prototype of HM's 1,000 rpm inertial crusher design that achieves a crushing ratio of around 40 and enables fine crushing with a high yield of fines. The crusher with a cone diameter of 600 mm will be put into mass production. Together with Uralmashzavod, a sample crusher with a cone diameter of 1650 mm is being designed.
Grinding, both dry and wet, is carried out mainly in drum mills. A general view of mills with end discharge is shown in fig. 2. The dimensions of drum mills are defined as the product of DxL, where D is the diameter of the drum, L is the length of the drum.
Mill volume
A brief description of the mills is given in Table. 70.
The productivity of the mill in weight units of a product of a certain size or class per unit volume per unit time is called specific productivity. It is usually given in tons per 1 m3 per hour (or day). But mill efficiency can also be expressed in other units, such as tons of finished product per kWh or kWh (energy consumption) per ton of finished product. The latter is used most often.
The power consumed by the mill is composed of two quantities: W1 - the power consumed by the mill at idle, without loading with crushing medium and ore; W2 - power to lift and rotate the load. W2 - productive power - is spent on grinding and the energy losses associated with it.
Total Power Consumption
The smaller the ratio W1/W, i.e. the larger the relative value W2/W, the more efficient the operation of the mill and the lower the energy consumption per ton of ore; W/T, where T is the capacity of the mill. The highest productivity of the mill under these conditions corresponds to the maximum power consumed by the mill. Since the theory of the operation of mills is not sufficiently developed, the optimal operating conditions of the mill are found empirically or determined on the basis of practical data, which are sometimes contradictory.
The specific productivity of mills depends on the following factors.
Mill drum rotation speed. When the mill rotates, balls or rods under the influence of centrifugal force
mv2/R = mπ2Rn2/30,
where m is the mass of the ball;
R - radius of rotation of the ball;
n is the number of revolutions per minute,
they are pressed against the wall of the drum and, in the absence of slip, rise with the wall to a certain height, until they break away from the wall under the influence of gravity mg and fly down the parabola, and then fall on the wall of the drum with ore and, upon impact, perform the work of crushing. Ho can be given such a number of revolutions that the He balls will break away from the wall (mv2/R>mg) and begin to rotate along with it.
The minimum rotation speed at which the balls (in the absence of slip) do not come off the wall is called the critical speed, the corresponding number of revolutions is called the critical number of revolutions ncr. In textbooks you can find
where D is the inner diameter of the drum;
d is the ball diameter;
h is the thickness of the lining.
The operating speed of the mill is usually determined as a percentage of the critical. As can be seen from fig. 3, the power consumed by the mill increases with an increase in the rotation speed beyond the critical one. Accordingly, the productivity of the mill should also increase. When operating at a speed higher than the critical one in a mill with a smooth lining, the speed of the mill drum is higher than the speed of the balls adjacent to the surface of the drum: the balls slide along the wall, rotating around their axis, abrade and crush the ore. With a lining with lifters and no slip, the maximum power consumption (and productivity) is shifted towards lower rotational speeds.
In modern practice, the most common mills with a rotation speed of 75-80% of the critical. According to the latest practice data, due to the increase in steel prices, mills are installed at a lower speed (slow-speed). So, at the largest molybdenum factory Climax (USA) mills 3.9x3.6 M with a 1000 hp motor. from. operate at a speed of 65% of the critical; at the new Pima factory (USA), the rotation speed of the rod mill (3.2x3.96/1) and ball mills (3.05x3.6 m) is 63% of the critical one; at the Tennessee plant (USA), the new ball mill has a speed of 59% of the critical, and the rod mill operates at an unusually high speed for rod mills - 76% of the critical. As seen in fig. 3, an increase in speed up to 200-300% can provide an increase in the productivity of mills by several times with their volume unchanged, but this will require a constructive improvement of the mills, in particular bearings, removal of scroll feeders, etc.
Crushing environment. For grinding in mills, manganese steel rods, forged or cast steel or alloyed cast iron balls, ore or quartz pebbles are used. As seen in fig. 3, the higher the specific gravity of the crushing medium, the higher the productivity of the mill and the lower the energy consumption per ton of ore. The lower the specific gravity of the balls, the higher the mill rotation speed must be to achieve the same throughput.
The size of the crushing bodies (dsh) depends on the feed size of the mill (dp) and its diameter D. Approximately it should be:
The smaller the food, the smaller the balls can be used. In practice, the following sizes of balls are known: for ore 25-40 mm = 100, less often, for hard ores - 125 mm, and for soft - 75 mm; for ore - 10-15 mm = 50-65 mm; in the second stage of grinding with a feed size of 3 mm dsh = 40 mm and in the second cycle with a feed size of 1 mm dsh = 25-30 mm; for regrinding concentrates or middlings, balls no larger than 20 mm or pebbles (ore or quartz) - 100 + 50 mm are used.
In rod mills, the diameter of the rods is usually 75-100 mm. The required amount of crushing medium depends on the speed of rotation of the mill, the method of its unloading and the nature of the products. Typically, at a mill rotation speed of 75-80% of the critical load, 40-50% of the mill volume is filled. However, in some cases, reducing the load of balls is more efficient not only from an economic, but also from a technological point of view - it provides more selective grinding without sludge formation. So, in 1953, at the Copper Hill factory (USA), the volume of ball loading was reduced from 45 to 29%, as a result of which the mill productivity increased from 2130 to 2250 tons, steel consumption decreased from 0.51 to 0.42 kg / t ; the copper content in the tailings decreased from 0.08% to 0.062% due to better selective grinding of sulfides and reduced waste rock overgrinding.
The fact is that at a mill rotation speed of 60-65% of the critical one in a mill with central unloading, with a small volume of ball loading, a relatively calm mirror of the pulp flow moving towards unloading is created, which is not stirred up by balls. From this flow, large and heavy ore particles quickly settle into a zone filled with balls and are crushed, while fine and large light particles remain in the flow and are unloaded without having time to be regrinded. When loading up to 50% of the mill volume, the entire pulp is mixed with balls and fine particles are regrinded.
Mill unloading method. Typically, mills are unloaded from the end opposite the loading end (with rare exceptions). Discharge can be high - in the center of the end (central discharge) through a hollow trunnion, or low - through a grate inserted into the mill from the discharge end, and the pulp that has passed through the grate is lifted by lifters and also unloaded through a hollow trunnion. In this case, part of the mill volume occupied by the grate and lifters (up to 10% of the volume) is not used for grinding.
The mill with a central discharge to the level of the drain is filled with pulp with beats. weight Δ. Balls with ud. weighing b in such a pulp become lighter in beats. weight. pulp: δ-Δ. i.e., their crushing effect decreases and the more, the smaller δ. In mills with low discharge, the falling vapors are not immersed in the slurry, so their crushing effect is greater.
Consequently, the productivity of mills with a lattice is greater by δ/δ-Δ times, i.e., with steel balls - by about 15-20%, with grinding ore or quartz pebbles - by 30-40%. So, when switching from central unloading to unloading through a grate, the productivity of mills increased at the Castle Dome factory (USA) by 12%, at Kirovskaya - by 20%, at Mirgalimsayskaya - by 18%.
This position is true only for coarse grinding or grinding in one stage. In fine grinding at fine feed, for example, in the second stage of grinding, the weight loss of the crushing body is less important and the main advantage of grate mills disappears, while their disadvantages - incomplete volume utilization, high steel consumption, high repair costs - remain, which makes preference mills with central discharge. So, tests at the Balkhash factory gave results not in favor of grate mills; at the Tennessee plant (USA), an increase in the diameter of the unloading pin did not give better results; at the Tulsiqua factory (Canada), when the grate was removed and the mill increased due to this volume, the productivity remained the same, and the cost of repairs and steel consumption decreased. In most cases, it is not advisable to put grate mills in the second grinding stage, when the work by abrasion and crushing is more efficient (rotation speed 60-65% of the critical) than the impact work (speed 75-80% of the critical).
Mill lining. Various types of linings are shown in fig. 4.
When grinding by abrasion and at speeds above the critical, smooth linings are advisable; when grinding by impact - linings with lifters. Simple and economical in terms of steel consumption is the lining shown in fig. 4, g: the gaps between the steel bars above the wooden slats are filled with small balls, which, protruding, protect the steel bars from wear. The productivity of mills is higher, the thinner and more wear-resistant lining.
During operation, the balls wear out and decrease in size, so the mills are loaded with balls of one larger size. In a cylindrical mill, large balls roll to the discharge end, so the efficiency of their use decreases. As tests have shown, when the rolling of large balls to unloading is eliminated, the productivity of the mill increases by 6%. To eliminate the movement of the balls, various linings have been proposed - stepped (Fig. 4, h), spiral (Fig. 4, i), etc.
At the discharge end of rod mills, large pieces of ore, falling between the rods, break their parallel arrangement when rolling over the loading surface. To eliminate this, the lining is given the shape of a cone, thickening it towards the discharge end.
Mill size. As the amount of ores processed increases, the size of the mills increases. If in the thirties the largest mills were 2.7x3.6 m in size, installed at the Balkhash and Sredneuralsk factories, then at the present time rod mills 3.5x3.65, 3.5x4.8 m, ball mills 4x3.6 m, 3 ,6x4.2 m, 3.6x4.9, 4x4.8 m, etc. Modern rod mills pass in an open cycle up to 9000 tons of ore per day.
Power consumption and specific productivity Tud are an exponential function of n - rotation speed, expressed as a percentage of the critical nk:
where n is the number of revolutions of the mill;
D is the mill diameter, k2 = T/42.4;
K1 - coefficient depending on the size of the mill and determined experimentally;
from here
T - the actual productivity of the mill is proportional to its volume and is equal to the specific productivity multiplied by the volume of the mill:
According to experiments in Outokumpu (Finland), m = 1.4, at the Sullivan factory (Canada) when working on a rod mill, m = 1.5. If we take m=1.4, then
T = k4 n1.4 * D2.7 L.
At the same number of revolutions, the productivity of the mills is directly proportional to L, and at the same speed as a percentage of the critical one, it is proportional to D2L.
Therefore, it is more profitable to increase the diameter of the mills, rather than the length. Therefore, ball mills usually have a larger diameter than the length. When crushing by impact in mills of larger diameter, the lining of which is with lifters, when the balls are lifted to a greater height, the kinetic energy of the balls is greater, so the efficiency of their use is higher. It is also possible to load smaller balls, which will increase their number and the productivity of the mill. This means that the performance of mills with small balls at the same rotation speed increases faster than D2.
In calculations, it is often assumed that productivity increases in proportion to D2.5, which is exaggerated.
The specific energy consumption (kW*h/t) is less due to the fact that the ratio W1/W decreases, i.e. the relative energy consumption for idling.
Mills are selected by specific productivity per unit volume of the mill, by a certain size class per unit of time, or by specific energy consumption per ton of ore.
The specific productivity is determined experimentally in a pilot mill or, by analogy, on the basis of data from the practice of factories operating with ores of the same hardness.
With a feed size of 25 mm and grinding to approximately 60-70% - 0.074 mm, the required volume of mills is about 0.02 m3 per ton of daily ore output or about 35 mill volume per 24 hours by class - 0.074 mm for Zolotushinsky, Zyryanovsky ores . Dzhezkazgan, Almalyk, Kojaran, Altyn-Topkan and other deposits. For magnetite quartzite - 28 and / day per 1 m3 of the mill volume by class - 0.074 mm. Rod mills, when grinding up to - 2 mm or up to 20% - 0.074 mm, pass 85-100 t / m3, and with softer ores (Olenegorsk factory) - up to 200 m3 / day.
Energy consumption during grinding per ton - 0.074 mm is 12-16 kWh / t, lining consumption is 0.01 kg / t for nickel steel and mills with a diameter of over 0.3 g and up to 0.25 /sg / g for manganese steel in smaller mills. The consumption of balls and rods is about 1 kg / t for soft ores or coarse grinding (about 50% -0.74 mm); for ores of medium hardness 1.6-1.7 kg/t, for hard ores and fine grinding up to 2-2.5 kg/t; the consumption of cast iron balls is 1.5-2 times higher.
Dry grinding is used in the preparation of pulverized coal fuel in the cement industry and less often in the grinding of ores, in particular gold-bearing, uranium, etc. In this case, grinding is carried out in a closed cycle with pneumatic classification (Fig. 5).
In the ore industry in recent years, short mills of large (up to 8.5 m) diameter with air classification have been used for dry grinding, and ore is used as a crushing and grinding medium in the form in which it is obtained from the mine - with a particle size of up to 900 mm . Ore with a particle size of 300-900 mm is immediately crushed in one stage to 70-80% - 0.074 mm.
This method is used to grind gold ores at the Rand factory (South Africa); at the Messina (Africa) and Goldstream (Canada) factories, sulfide ores are crushed to a flotation size - 85% - 0.074 mm. The cost of grinding in such mills is lower than in ball mills, while the cost of classification is half of all costs.
At gold recovery and uranium plants, when using such mills, it is possible to avoid contamination with metallic iron (abrasion of balls and lining); iron, absorbing oxygen or acid, impairs the extraction of gold and increases the consumption of acid in the leaching of uranium ores.
Selective grinding of heavier minerals (sulfides, etc.) and the absence of sludge formation leads to an improvement in metal recovery, to an increase in the settling rate during thickening and filtration rate (by 25% compared to grinding in ball mills with classification).
Further development of grinding equipment, apparently, will follow the path of creating centrifugal ball mills that simultaneously perform the role of a classifier or work in a closed cycle with classifiers (centrifugal), like existing mills.
Grinding in vibratory mills belongs to the field of ultra-fine grinding (paints, etc.). Their use for grinding He ores has gone beyond the experimental stage; The largest volume of tested Bibromills is about 1 m3.
We can supply crushing, grinding and concentration equipment for the processing of copper ore, and processing lines, DSC provide complete solutions
Complex for processing copper ore
Crushing and sorting complex for processing copper ore
Crushing and grinding equipment for sale
Various crushing, milling, screening equipment manufactured by Shiban solve problems in the processing of copper ore.
Peculiarities:
- High performance;
- Selection, installation, training, operation and repair services;
- We supply high quality spare parts from the manufacturer.
Crushing equipment for copper ore:
Various crushing, milling, screening equipment, such as rotary crusher, jaw crusher, cone crusher, mobile crusher, vibrating screen, ball mill, vertical mill are designed to process copper ore in the production line to produce copper concentrate, etc.
In an open pit, raw materials are first transported in the main gyratory crusher and then fed to the cone crusher for secondary crushing. According to the requirement of the customer, it is possible to equip the stone crusher at the tertiary stage of crushing, which allows crushing copper ore below 12mm. After sorting into a vibrating screen, suitable crushed materials are either finished as a final fraction or sent to a further process for the production of copper concentrate.
As a major manufacturer of crushing equipment and milling equipment in China, SBM provides various solutions for mining and processing copper ore: crushing, milling and screening. During the primary crushing process, copper ore is crushed into small pieces less than 25 mm in diameter. To get finer finished products, you need to buy secondary or tetichny crushers. The overall energy consumption is reduced significantly. Comparing work efficiency and , we find what does the job more efficiently in tertiary crushing. And if the installation of the same number of secondary and tertiary crushers, within the operation "is transferred from the tertiary and secondary crushers, where the liner wear is three times less, which greatly affects the cost reduction of the crushing process.
Crushed copper ores are then sent to the storage hopper via a belt conveyor. Our ball mills and others provide grinding of copper ores to the required fraction.
Extraction and processing of copper ore:
Copper ore can be mined either in an open pit or underground mines.
After the blast at the quarry, the copper ores will be loaded under the action of heavy trucks, then transported in the primary crushing process to crush the copper ores to 8 inches or less. The vibrating screen performs screening of crushed copper ores, according to the customer's requirement, they pass through the belt conveyor into the quality of the finished fraction, if you need powders, then the crushed copper ores are sent to the mill equipment for further grinding.
In a ball mill, the crushed copper ore will be processed to about 0.2mm using a 3 inch steel ball. The copper ore slurry is finally pumped into the flotation deck with fine sulfide ores (about -0.5mm) to recover the copper.
Feedback on DSO for copper ore:
" We have purchased stationary crushing and screening equipment for large-scale copper ore processing. " ---- Customer in Mexico