First, the nature of chalcopyrite
Copper sulfide minerals are mainly chalcopyrite (CuFeS 2), chalcocite (Cu 2 S), bornite (Cu 5 FeS 4), blue copper (Cu 2 S Â· CuS 2) , tennantite (Cu 12 As 4 S 13 ), etc., the most important ones are chalcopyrite and chalcopyrite, and China is dominated by chalcopyrite.
Chalcopyrite containing Cu34.56%, brass, often due to surface oxidation significant gold yellow, purple color, etc. POH, it looks like pyrite, but the hardness is small (3.0 to 4), a density of 4.1 to 4.3 g/cm 3 , the streak is greenish black, the crystal structure is tetragonal, often in the form of granular or dense block aggregates, which is the most important mineral raw material for copper smelting and preparation of copper compounds. Chalcopyrite in the surface oxidation zone can often produce a series of secondary copper-bearing minerals, such as copper blue, malachite, azurite, cuprite, chalcopyrite and porphyrite, so that the lower part of the oxidized zone is formed. A secondary enrichment zone.
In the crystal structure of chalcopyrite, each sulfide ion is surrounded by four metal ions (two copper ions, two iron ions) distributed at the apex angle of the tetrahedron, and all the orientation tetrahedrons have the same orientation. . Because chalcopyrite has a high lattice energy, and the position of sulfur ions in the crystal structure is in the inner layer of the crystal lattice relative to copper and iron, chalcopyrite has greater stability to oxidation. .
The chalcopyrite has good surface hydrophobicity in neutral and weakly alkaline media, and forms an iron hydroxide film on the surface of the strongly alkaline medium, which reduces the hydrophobicity.
The most commonly used collectors for flotation chalcopyrite are xanthate, black medicine, and sulfur-nitrogen collectors. Chalcopyrite has good floatability in the wide pH range (4~12) and is easily inhibited by cyanide and lime in alkaline media.
Second, the nature of stibnite
Bismuth is a relatively rare element, and its content in the earth's crust is only about 3.4 Ã— 10 -4 %. In the natural world, it is mostly in the form of oxides, sulfides, sulfur-containing salts and other compounds, and only a small amount of elemental lanthanum. The known bismuth minerals are bismuth ore (Bi 2 S 3 ), bismuth ore [Bi 2 CO 3 Â·(2~3)H 2 O], bismuth (Bi 2 S 3 ), and strontium ore (nBi 2 ) There are more than 50 kinds of O 3 Â·mCO 2 Â·H 2 O), copper bismuth ore (3Cu 2 SÂ·4Bi 2 O 3 ), and bismuth lead ore (2PbSÂ·Bi 2 S 3 ). Mine, foam mine, é“‹åŽ and natural é“‹. It is often associated with non-ferrous metals such as lead, copper, tin , antimony and tungsten.
The bismuth ore (Bi 2 S 3 ) contains 81.3% bismuth, the tin-white color of the micro-belt ash, the surface is often yellow or plaque-colored, the streak is lead gray, the hardness is 2 to 2.5, and the density is 6.8 g/cm 3 . , Orthogonal (oblique) crystal system, the crystal is long column or needle-like, the column mask is vertical stripes, and the aggregate is radioactive column or dense granular. The stibnite is the most important mineral raw material for refining, but it rarely forms independent deposits. It is mainly found in tungsten-tin high-temperature hydrothermal deposits and contact metasomaties. The stibnite forms antimony oxides after surface weathering (such as Yuhua). Or carbonate (such as soot ore).
The bismuth ore (Bi 2 S 3 ) has a chain structure, and the Bi-S in the chain is linked by a covalent bond, and the bond distance is short; the chain bonds are linked by molecular bonds, and the bond distance is long. When the force is applied, the Bi-S molecular bond breaks between the chains, and the (010) surface cleavage is complete. Therefore, the molecular bonds on the cleavage surface of the stibnite are weak, and the ability to adsorb water molecules is not strong.
The stibnite mine has the same natural floatability as the molybdenum ore, and is easily collected by xanthate, black medicine, black medicine and sulfur nitrogen collectors. The stibnite is not inhibited by cyanide. When it is separated from minerals such as iron sulfide, copper and arsenic, cyanide can be used to suppress other sulfide minerals and float.
3. Research status of separation of chalcopyrite and stibnite
Copper beryllium minerals are often symbiotic or associated with tungsten minerals. For example, Jiangxi Tieshan tungsten ore contains molybdenum, copper, zinc and zinc minerals, Jiangxi Xiushui Xianglushan tungsten ore contains copper beryllium minerals, and Yunnan Maguan tungsten ore contains copper and niobium minerals. The separation of copper matte is a difficult task in mineral processing , but there are relatively few studies on the separation of copper matte at home and abroad. Many mines in our country are unable to obtain qualified antimony concentrate due to the failure to separate the copper matte, which causes the loss of plutonium to be quite serious. Therefore, research and development of a reasonable copper matte separation process and pharmaceutical system is of great significance. At present, the separation methods of copper matte mainly include re-election, flotation and wet method. However, due to the poor re-election separation effect, this paper focuses on the research status of copper-bismuth separation from the aspects of flotation and wet method.
(1) Research status of copper raft flotation separation
The floatability of chalcopyrite and stibnite is very similar, and there is a certain difficulty in the separation of copper matte. At present, the main domestic use of copper bismuth flotation separation is cyanide-reducing copper floating raft and cyanide-free copper floating copper.
Liu Rihe used a copper-copper mixed-copper-buffering process when sorting a copper-bismuth sulfide ore. The copper-copper mixed float was used as a collector for the scutellaria, and the pyrite was inhibited by lime. The separation operation was NaCN and lime. The mixed inhibitors inhibited copper rafts and obtained better indicators.
Zhang Santian conducted a comparative test of molybdenum, bismuth-copper, molybdenum, copper-bismuth and other floatable processes. The molybdenum and bismuth-copper processes used sodium cyanide to suppress copper, molybdenum and copper in the floating molybdenum crucible. The bismuth process is selected from the use of sodium sulfite to inhibit strontium minerals in floating molybdenum. The test results show that the molybdenum and bismuth-copper processes are difficult to obtain independent copper concentrates. The molybdenum and copper-bismuth processes are difficult to activate due to the inhibition of strontium minerals, resulting in 56.98% of cesium entering the tailings cannot be recovered; The molybdenum-copper concentrate concentrates at the same time and then separates, so it does not affect the flotation of the later difficult-to-float minerals. The obtained indexes are better than the first two processes.
Luojian Zhong et copper - lead-bismuth separation were studied, compared heavy chromate separation method, a method of oxygen sulfur, carboxymethyl cellulose method, a cyanide process, the results show that K 2 Cr 2 O 7 As an inhibitor of lead bismuth, flotation separation is the best, and chalcopyrite still maintains good floatability. In addition, the removal of lead sputum surface collector is also the key, the drug removal effect is not good, copper-lead bismuth is not separable.
Wang Zhengde used a warming-sulfite flotation separation process for the sulfide ore mixed concentrate containing molybdenum and copper bismuth to realize the separation of copper bismuth. The principle flow is as follows: adding sodium sulfide to stir off the drug, grinding, steaming directly into the flotation tank for heating (50-60 Â° C), adjusting the pH value of the slurry to about 5.5 with sulfuric acid, first suppressing with sodium sulfite agent for coal and oil floating molybdenum pine oil, black powder and then tetrabutylammonium butyl xanthate floating copper, bismuth remained in the bottom. This process simplifies the process compared to cyanide flotation, saving the amount of chemicals and reducing environmental pollution.
The copper-defining raft technology is applied less and less because it usually uses cyanide and is seriously polluted by the environment. The key to suppressing the floating copper process is to find effective inhibitors of stibnite, otherwise it is difficult to achieve better recovery of bismuth.
(II) Research status of copper-wet wet separation
Usually, the sulphide in the ore is close to the sulphide properties of other sulfide minerals, the oxidized cerium-containing minerals are associated with the hydrated iron hydroxide, and the cerium minerals are densely symbiotic with other minerals in the ore and the size of the impregnation is very fine. It is difficult to completely separate the strontium mineral from other minerals due to flotation. The concentrate contains low strontium and the recovery rate is not high. Therefore, in recent years, the research on the separation of copper bismuth has also made a lot of progress.
At present, the wet separation of copper matte is mainly carried out by using hydrochloric acid or chlorine salt as a leaching agent for chemical leaching. The main purpose is to use copper and bismuth in the leaching medium to achieve different separation speeds. Sometimes it is beneficial to add some oxidants properly. Improve the effect of selective leaching.
Sui Chaoke conducted a leaching test on hydrochloric acid mixed concentrate produced by conventional flotation with hydrochloric acid. Mixing concentrate containing Bi15.14%, Cu7.65%, Zn8.07% , Au33.5g / t, Ag2072g / t, leached hot hydrochloric acid, bismuth, copper, zinc dissolves, the insoluble gold and silver, the residue left Forming gold and silver concentrates. After the solution is cooled, it is diluted with water, and the ruthenium chloride is hydrolyzed to form a bismuth chloride precipitate. After filtration and drying, it is a hydrazine product; after the filtrate is added with zinc or iron to replace the sponge copper, the zinc is recovered from the residual liquid. The obtained bismuth oxychloride contains about 68% of ruthenium, the recovery rate is 90% to 95%, and the sponge copper contains 80% of copper.
Chen Mingrui studied a new process for extracting antimony from tungsten fine mud sulfide ore by using ferric chloride leaching-iron filings. The results show that the metal sulfide minerals can be selectively selected in ferric chloride solution by controlling the leaching conditions due to the different reduction potentials and dissolution rates of metal sulfide minerals in acidic ferric chloride solution. The ease of leaching and leaching is ranked as: fluorite ore > chalcopyrite > galena (a stibnite and silver-bearing sulphate minerals) > sphalerite > chalcopyrite > pyrite > molybdenite. According to the analysis of raw material properties, strontium and some lead metals were extracted from tungsten fine mud sulfide ore by one-step leaching method using ferric chloride solution. The leaching solution was replaced by iron filings to obtain sponge sputum, and sulfide minerals such as copper, zinc and iron remained in the leaching slag. in. The sponge obtained by the test contains 40% strontium, the recovery rate of strontium is 80%, the leaching slag contains 11% to 13% of copper, and the strontium content is very low, which can be sold as low-grade copper concentrate.
Through a large number of experiments, Zhang Ronghua found that the bleaching powder oxidation-hot hydrochloric acid leaching-iron filing process can effectively separate and recover base metals from copper-sulfur concentrate. The effects of leaching temperature, hydrochloric acid dosage, leaching time and bleaching powder dosage on the recovery rate of ruthenium and copper loss rate were studied. The results showed that: (1) bleaching powder is a strong oxidant, and its aqueous solution can selectively oxidize ruthenium and silver. Minerals, in the presence of industrial hydrochloric acid, can form a combined oxidation with ferric chloride. It is this combined oxidation that provides a new way for the separation of bismuth and copper in copper concentrates, and the use of bleaching powder as an oxidant. Reduce production costs, reduce copper metal losses, and improve the grade of antimony concentrate. (2) Heating leaching is the key to obtain higher recovery rate. Compared with normal temperature leaching, the recovery rate of enthalpy of national hot leaching can be increased by 35 percentage points, and the leaching time can be appropriately shortened. (3) Stirring during leaching can increase the leaching rate of bismuth by 5 to 10 percentage points. The test obtained a sponge crucible with a grade of more than 80% and a recovery rate of 90%, and the copper metal loss rate was below 1%.
Tang Guanzhong developed a new method for leaching low-grade barium sulfide by chlorination with HCl+CuCl 2 +CaCl 2 system. Under the conditions of initial acid concentration of 50-60 g/L, temperature of O 55 Â° C, and Cu 2 + concentration of 6-8 g/L, the total recovery of Bi is 97%, and the loss rate of copper is 3 %. After the sinking, the liquid is oxidized by air to remove iron, regenerate hydrochloric acid, and reactivate the copper ions, which can be recycled. The whole process has no waste water and exhaust gas.
Wang Zhengde et al. used manganese dioxide and hydrochloric acid selective leaching process to reduce the content of antimony in copper concentrate, and obtained good indicators. The effects of grinding fineness, manganese dioxide dosage, hydrochloric acid concentration, leaching temperature, leaching time and liquid-solid ratio on leaching were studied. It was found that the amount of manganese dioxide and hydrochloric acid concentration are the key factors affecting the effect of selective leaching and haze. With the decrease of the amount of manganese dioxide (increased hydrochloric acid concentration), the amount of strontium in the leaching residue decreases first and then increases, and the amount of copper decreases. The temperature and time have little effect on the leaching of copper, but the leaching rate will follow The increase in temperature and the increase in time increase. Under suitable conditions, the leaching rates of copper and bismuth were 7.12% and 61.43%, respectively, which achieved the purpose of selective leaching and hail.
The copper beryllium separation method can achieve higher recovery rate, but it needs to solve the problems of low production cost, lightening equipment corrosion and avoiding environmental pollution.
Fourth, the conclusion
Finding the selective inhibitor of stibnite and developing a new flotation process for the separation of copper bismuth is the key to improving the separation efficiency of copper bismuth; reducing cost, reducing corrosion and pollution is a difficult problem in the separation of copper bismuth, and research and development Efficient biological bacteria and bioleaching are undoubtedly an effective way to solve these problems.
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