In the bowels of the earth there is a fairly large number of different minerals that can be used to release various materials. Copper ore is quite widespread - it is used for processing and obtaining various substances that are applicable in industry. It should be borne in mind that in such an ore, which contains copper, other minerals may also be present. It is recommended to use earthen rock, which includes at least 0.5-1% of the metal.
Classification
A huge amount of a wide variety of copper ores is being mined. The classification is based on their origin. The following groups of copper ores are distinguished:
- Pyrite has become quite widespread. The rock is represented by a combination of iron and copper, has a large number of various inclusions and veins of other impurities.
- Stratiform is represented by a combination of copper shales and sandstones. This kind of breed has also become widespread, as it is represented by a large deposit. The main characteristics can be called a simple reservoir form, as well as a uniform distribution of all useful components. Due to this, copper rock of this type is most in demand, as it allows you to ensure productivity at the same level.
- Copper-nickel. This ore is characterized by massive interspersed textures of cobalt and gold, as well as platinoids. The deposits are in vein and reservoir form.
- Porphyry copper or hydrothermal. Copper ore deposits of this kind contain a large concentration of silver and gold, selenium and other chemicals. In addition, all useful material are in a higher concentration, due to which the breed is in demand. It is extremely rare.
- Carbonate. This group includes iron-copper and carbonatite ore. It should be borne in mind that this breed was found only in South Africa. The developed mine belongs to massive alkaline rocks.
- Skarnova - a group that is characterized by a local location in the most various breeds. Characteristic properties include small size and complex morphology. It should be borne in mind that in this case, the ore containing copper has a high concentration. However, the metal is unevenly distributed. Mined rocks have a copper concentration of about three percent.
Copper is practically not found, for example, like gold, in the form of massive nuggets. The largest similar education the deposit can be named North America, whose mass is 420 tons. With 250 types of copper, only 20 of them are widely used in pure form, others are used only as alloying elements.
Deposits of copper ores
Copper is considered the most common metal used in a wide variety of industries. Deposits of copper ore are found in almost all countries. An example is the discovery of a field in Arizona and Nevada. Copper ore is also mined in Cuba, where oxide deposits are common. Chloride formations are mined in Peru.
The use of the extracted copper mixture is associated with the production of various metals. There are two main copper production technologies:
- hydrometallurgical;
- pyrometallurgical.
The second method involves fire refining of the metal. Due to this, the ore can be processed in almost any volume. In addition, the effect of fire makes it possible to isolate almost all useful substances from the rock. Pyrometallurgical technology is used to isolate copper from rock that has a low degree of metal enrichment. The hydrometallurgical method is used exclusively for processing oxidized and native rocks, which also have a low concentration of copper.
In conclusion, we note that today copper is included in almost all alloys. Its addition as an alloying element allows you to change the basic performance.
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 explosion at the quarry, copper ores will be loaded by heavy trucks, then transported through the primary crushing process to be crushed copper ore up 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
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 concentrating 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 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, 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. Difficulties explained chemical reactions occurring 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.
Ores or technogenic raw materials extracted from the bowels of the earth in most cases cannot be directly used in metallurgical production and therefore go through a complex cycle of successive operations. preparation for blast furnace. Note that when ore is mined by opencast mining, depending on the distance between the blast holes and the size of the excavator bucket, the size of large blocks iron ore can reach 1000-1500 mm. In underground mining, the maximum size of a piece usually does not exceed 350 mm. In all cases, the extracted raw material also contains a large amount of fine fractions.
Regardless of the subsequent scheme for preparing the ore for smelting, all mined ore goes through, first of all, the stage primary crushing, since the size of large pieces and blocks during mining far exceeds the size of an ore piece, the maximum allowable according to the conditions of blast-furnace smelting technology. Specifications for lumpiness, depending on the reducibility, the following maximum size of ore pieces is provided: up to 50 mm for magnetite ores, up to 80 mm for hematite ores and up to 120 mm for brown iron ore. The upper limit of the particle size of agglomerate pieces should not exceed 40 mm.
Figure 1 shows the most common crusher installations in crushing and screening plants. Schemes a and b solve the same problem of crushing ore from
a - "open"; b - "open" with preliminary screening; c - "closed" with preliminary and verification screening
At the same time, the principle “do not crush anything superfluous” is implemented. Schemes a and b are characterized by the fact that the size of the crushed product is not checked, i.e., the schemes are "open". Experience shows that in a crushed product there is always a small number of pieces, the size of which is somewhat larger than the specified one. In "closed" ("closed") circuits, the crushed product is again sent to the screen to separate insufficiently crushed pieces with their subsequent return to the crusher. With “closed” ore crushing schemes, compliance with the upper limit of crushed product size is guaranteed.
The most common types of crushers are:
- conical;
- jaw crushers;
- roller;
- hammer.
The device of crushers is shown in fig. 2. The destruction of pieces of ore in them occurs as a result of crushing, splitting, abrading forces and impacts. In the Black jaw crusher, the material introduced into the crusher from above is crushed by the oscillating 2 and stationary 1 cheeks, and in the McCouley cone crusher, by the fixed 12 and rotating internal 13 cones. The shaft of the cone 13 enters the rotating eccentric 18. In the jaw crusher, only one stroke of the movable jaw is working, during the reverse stroke of the jaw, part of the crushed material has time to leave the working space of the crusher through the lower outlet slot.
 |
| Figure 2. Structural diagrams of crushers a - cheek; b - conical; c - mushroom-shaped; g - hammer; d - roll; 1 - fixed cheek with an axis of rotation; 2 - movable cheek; 3, 4 - eccentric shaft; 5 - connecting rod; 6 - hinged support of the rear spacer cheek; 7 - spring; 8, 9 - mechanism for adjusting the width of the unloading gap; 10 - thrust of the closing device; 11 - bed; 12 - fixed cone; 13 - movable cone; 14 - traverse; 15 - suspension hinge of the movable cone; 16 - cone shaft; 17 - drive shaft; 18 - eccentric; 19 - damping spring; 20 - support ring; 21 - regulating ring; 22 - cone thrust; 23 - rotor; 24 - impact plates; 25 - grate; 26 - hammer; 27 - main frame; 28 - crushing rolls |
The capacity of the largest jaw crushers does not exceed 450-500 t/h. Typical for jaw crushers are cases of press-fitting of the working space during crushing of wet clay ores. In addition, jaw crushers should not be used for crushing ores with a slate slate structure of the piece, since individual tiles, if their long axis is oriented along the axis of the slot for dispensing crushed material, can pass through the working space of the crusher without being destroyed.
The supply of jaw crushers with material must be uniform, for which the apron feeder is installed from the side of the crusher's fixed jaw. Jaw crushers are usually used for crushing large pieces of ore (i = 3-8). Electricity consumption for crushing 1 ton of iron ore in these plants can vary from 0.3 to 1.3 kWh.
In a cone crusher, the axis of rotation of the inner cone does not coincide with the geometric axis of the fixed cone, i.e., at any moment, ore crushing occurs in the zone of approach of the surfaces of the inner and outer fixed cones. At the same time, in the remaining zones, the crushed product is dispensed through the annular gap between the cones. Thus crushing of ore in a cone crusher is carried out continuously. Achievable productivity is 3500-4000 t/h (i = 3-8) with power consumption for crushing 1 ton of ore 0.1-1.3 kWh.
cone crushers can be successfully used for ores of any type, including those with a layered (platy) structure of the piece, as well as for clay ores. Cone crushers do not need feeders and can operate “under the rubble”, i.e. with a working space completely filled with ore coming from a bunker located above.
The Simons Short Cone Mushroom Crusher differs from the conventional cone crusher in that it has an elongated crushed product discharge zone, which ensures that the material is completely crushed to the desired size of the pieces.
AT hammer crushers crushing of ore is carried out mainly under the influence of blows on them by steel hammers mounted on a rapidly rotating shaft. At metallurgical plants, limestone is crushed in such crushers, which is then used in sinter shops. Brittle materials (eg coke) can be crushed in roller crushers.
After primary crushing, rich low-sulphurous ore with a fraction of > 8 mm can be used by blast-furnace shops, a fraction Some of the fine fractions are still absorbed by the furnace, sharply worsening the gas permeability of the charge column, since small particles fill the space between larger pieces. It must be remembered that the separation of fines from the blast-furnace charge in all cases gives a significant technical and economic effect, improving the course of the process, stabilizing dust removal at a constant minimum level, which in turn contributes to a constant heating of the furnace and a reduction in coke consumption.
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 totality and sequence of methods in 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 the method are high flow reagents-regulators of the environment for flotation in an alkaline medium, insufficiently high recovery of copper during flotation due to oxide copper minerals coming after leaching of large particles, screening of copper minerals by a 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 in the grinding of ore depends on mineral composition ores, 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 grade leads to a high concentration of copper in solution, which reduces driving force mineral dissolution and leaching rate, compared to low solids leaching.
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 copper content in the leaching cake and the load on the leaching cake flotation enrichment 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. Liberation from suspensions can be carried out most in a simple 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. Modern method extraction of copper from solutions is a 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. top scores flotation enrichment is achieved using several collectors from a number 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 an 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
