Common copper oxide minerals are malachite, azurite, cuprite, chrysocolla like. Oxidized zone of sulphide deposits produced by malachite in copper, often associated with other copper-bearing minerals ( blue copper, chalcopyrite, cuprite, natural copper, etc. ) . Malachite is a copper-containing carbonate mineral ( basic copper carbonate ) with a chemical composition of Cu 2 (OH) 2 CO 3 , a CuO content of 71.9% , a CO 2 content of 19.9% , and a H 2 O content of 8.15% . The azurite is also a copper-bearing carbonate mineral with the same chemical composition as malachite, but with a different mineral structure. The cuprite is a red oxide mineral, which is soft and dense. It is generally formed by the weathering of copper sulfide. The chemical composition is Cu 2 O and the copper content is as high as 88.8% . It is an important Copper ore minerals. The chrysocolla is a hydrated silicate colloidal copper mineral with unrestricted composition and properties. The chemical formula is CuSiO 3 · nH 2 O and contains 36.1% copper . 1. Vulcanization flotation method The surface of the copper oxide mineral is dominated by saturated ionic bonds. Therefore, the mineral surface has strong polarity and chemical activity, and it has a great attraction to polar water molecules, and thus exhibits hydrophilicity. After addition of sodium sulfide, copper oxide surface rapid adsorption HS - or S2 -, the film was sulphides, strengthen adsorption of the collector, to enhance its hydrophobic surface, to improve the floatability, enabling Effective flotation of copper oxide. The copper oxide minerals which can be treated by the vulcanization method are mainly copper carbonate minerals such as malachite, azurite, etc., and can also be used for flotation of copper ore, and if the malachite is not specially treated in advance, The vulcanization effect is very poor and cannot even be vulcanized. The key to the vulcanization flotation process is to strictly control the amount of sodium sulfide, which is both an activator of copper oxide and an inhibitor of sulfide or an inhibitor of sulfide ore after vulcanization. That is to say, a suitable amount of sodium sulfide is an activator, and after exceeding the optimum amount, sodium sulfide is an inhibitor. In order to reduce or prevent such inhibition, it is often used in industrial production for the purpose of controlling the concentration of the vulcanizing agent by means of a staged dosing or other methods. At present, many selective plants use the preferential flotation method to treat mixed copper ore ( oxidation rate 10%~30%) , that is, float the easily floated copper sulfide minerals first, and then float the sulfided copper oxide minerals. IN Babich et al [5] discussed the separation process of Udokan mixed copper ore and determined the optimum amount of calcium oxide, the appropriate pH value for flotation of copper sulfide and copper oxide minerals . The experiment found that the optimum pH of the flotation copper sulfide mineral is 9 and the optimum pH of the flotation copper oxide mineral is 10 . The pH value can be divided into two stages. In the first stage, calcium oxide is added during the grinding to raise the pH of the slurry from 7 to 9. In the second stage, sodium sulfide is added to the slurry to make the pH of the slurry from 8 increased to 10 . In the first stage, copper sulfide minerals are floated and copper oxide minerals are floated in the second stage. Tests have shown that the optimum amount of calcium oxide is 2000 g/t and the optimum amount of sodium sulfide is 1 200 g/t . The two-stage flotation increased the copper recovery from 84.2% to 89% , which is a 4.8% increase in copper recovery compared to mixed flotation . Currently applying this method of mineral processing plant in Hubei large Yetong tonglushan concentrator, Jiangsu Tongling Chemical Industry Group Xinqiao mining companies. 2. Organic acid flotation method The organic acid collector can be physically adsorbed or chemically adsorbed on the surface of the mineral. It is usually adsorbed on the outer layer of the double layer of the mineral surface. It is usually a single layer of adsorption. This adsorption belongs to chemical adsorption. The adsorption of the diffusion layer on the outer layer of the electric layer is physical adsorption, and the adsorption of the organic acid collector on the surface of the mineral is generally in a multi-layer adsorption state. The organic acid collector is easily adsorbed on the surface of the silicate mineral to improve the floatability of the chrysocolla. An organic acid, also known as flotation flotation method, and when using a fatty acid soaps as collector flotation agent, useful to add inhibitors silicate gangue minerals, phosphate and carbonate slurry adjusting agent and the like. Fatty acid and its soap collector can float flounder well well. The test results of flotation of cyanite with different carbon chain length fatty acids show that within a certain range, as long as the chain is long enough, the harvesting ability is strong. The dosage of the medicament is small. Obtained in practice by the production of more mixed C 10 ~ C 20 saturated or unsaturated carboxylic acid. 3. Ammonia leaching - sulfide precipitation - flotation method Ammonia leaching - sulphide precipitation - flotation method is the addition of elemental sulphur ( sulfur powder ) during the pressure leaching process . After the copper oxide mineral is dissolved by ammonia and carbon dioxide, it is precipitated as copper sulphide. Pulp without solid-liquid separation is directly distilled in the recovery after 2, the precipitated "artificial copper sulfide", and any original natural ore together with a conventional copper sulfide flotation recovery of NH 3 and CO. This method is suitable for the inlay of very fine copper oxide minerals. In the experimental study of Tangdan's refractory copper oxide, a good sorting index was obtained. The recovery rate of copper was increased by 17% , and the concentrate grade was more than doubled. The principle process is shown in Figure 1 . Segregation - flotation, also known reduction roasting chloride - flotation method, copper oxide ore is crushed to the appropriate particle size, a certain amount of salt and coal powder was heated to a certain temperature, the hydrogen chloride gas produced by the decomposition of salt Copper oxide reaction, see reaction (1) to reaction (3) . Due to the presence of the carbonaceous reducing agent, the volatilized Cu 3 Cl 3 is adsorbed on the surface of the carbon particles and reduced to metallic copper. The residual carbon can be recovered by the conventional flotation method and the metal mineral adsorbed thereon can be separated from the iron and the gangue. Achieve copper enrichment. 2NaCl+H 2 O+ySiO 2 → 2Na 2 O · ySiO 2 +2HCl(g) (1) 12CuO+12HCl → 4Cu 3 Cl 3 +6H 2 O+3O 2 (2) 3Cu 2 O+6HCl → 2Cu 3 Cl 3 +3H 2 O (3) ATGrotowski conducted a detailed study on the separation method. The optimum process parameters were: ore particle size 0.3 mm , coal powder 1.5% , NaCl content 1.0% , separation temperature 700-800 °C, and separation time 1~1.5 h . In the treatment of sulfurized copper oxide mixed ore, oxidative roasting is first performed to completely oxidize the ore. The separation roasting-flotation method can increase the recovery rate of direct flotation by 12%~22% and the grade by 1.5%~4.8% . Studies have shown that copper sulfide is deposited on coal particles rather than metallic copper. The segregation method can recover valuable metals such as copper and silver from ore, but the heat energy consumption is large, the cost is high, the labor conditions are poor, and there are few examples of large-scale industrial production. Production is carried out using an isolation-flotation process. 5. Vulcanization roasting - flotation method Vulcanization roasting-flotation method [1] is a vulcanization reaction on the surface of copper oxide mineral at a certain temperature, copper sulfide is formed on the surface to increase its floatability, and flotation can be carried out by the flotation system of flotation sulfide. Copper minerals are enriched in foam products. At the same time, the specific surface area of ​​the fine-grained slime is greatly reduced during the roasting process, causing the agglomeration of the fine-grained slime, eliminating the bad influence of the slime on the flotation result, which greatly facilitates the flotation process of the copper ore. Thus copper ore that cannot be directly processed by beneficiation or other methods finds a new way of recycling. The chemical reaction is shown in the reaction formula (4) , and the process flow is shown in FIG. 2 . Cu 2 CO 3 (OH) 2 (s)+S 2 (g) → Cu 2 S(s)+SO 2 (g)+H 2 O(g)+CO 2 (g) (4) 6. Chemical pretreatment - flotation Chemical pretreatment - flotation method, adding H 2 SO 4 to leaching Cu 2+ in the form of CuSO 4 , adding fine iron powder, replacing copper, and then collecting copper with xanthate. This method is applicable to ores of complex copper oxide ore, such as non-floating minerals such as chrysocolla, or refractory copper oxide ore with very high mud content, which contains carbonate and iron. , manganese compound, and the embedded cloth is fine in size and easy to mud. When leaching, 0.5%~3% dilute sulfuric acid solution is generally used . The amount of acid needs to vary with the ore property, the low is 2.3~11 kg/t , and the high is 35~45kg/t . After the copper is leached, it is replaced with iron powder. The iron powder requirement theoretically requires only 0.88 kg of iron to replace 1 kg of copper , but in actual production, 1.5 to 2.5 kg of iron is required to replace 1 kg of copper . At the time of displacement, an excess of residual iron powder must be maintained in the solution to prevent the already reduced copper from being oxidized again. The unreacted residual iron powder can be recovered by magnetic separation. Precipitated copper flotation (pH value of 3.7 to 4.5) in an acidic medium, with a collector or cresol Aerofloat dixanthogen, undissolved copper sulphide minerals and metallic copper can be precipitated together with the float Come. H. Razavizadeh et al [9] leached the copper oxide ore of Sharcheshmeh with sulfuric acid , which contained 2% to 4.1% of soluble copper. XRD analysis Malachite is the primary copper minerals, mainly quartz gangue. The experiment explored the effects of sulfuric acid concentration (10~20 g/L) , leaching temperature (15~50 °C ) , and leaching time ( up to 3 h) on copper recovery. When the concentration of sulfuric acid was 20g/L , the effect on the dissolution of malachite was the best. After 120 minutes of leaching , the copper-bearing ore was completely dissolved, and almost no leaching was observed. The sample dissolves quickly at the beginning and then the dissolution rate becomes very slow. When the concentration of sulfuric acid and the leaching temperature are increased, the dissolution rate of the sample is significantly accelerated. Scanning electron microscopy showed that some of the reaction particles had a needle-like structure. Chemical reaction kinetics studies show that the malachite dissolution process is divided into two stages. In the first stage, 85% of malachite dissolves rapidly and the required activation energy is 20.6 kJ/mol . In the second stage, the next 15% malachite dissolves very slowly and the activation energy required for dissolution is 87.6 kJ/mol . The chemical reaction process is as shown in the reaction formula (5) to the reaction formula (7) . Cu 2 (OH) 2 CO 3 +2H 2 SO 4 → 2CuSO 4 +CO 2 +3H 2 O (5) Cu 3 (OH) 2 (CO 3 ) 2 +3H 2 SO 4 → 3CuSO 4 +2CO 2 +4H 2 O (6) CuO+H 2 SO 4 → CuSO4+H 2 O (7) Chemical pretreatment - flotation process has been successfully applied to the US Butte plant. Some scholars have also studied the chemical pretreatment-flotation process of refractory copper oxide ore with deep oxidation and poor floatability in a copper mine in Xinjiang, and achieved a good copper recovery rate of 84.22% and a copper concentrate grade of 45.09% . index. In order to develop such refractory copper oxide ore resources, in recent years, the chemical pretreatment-flotation process has attracted attention and has been widely used in practice and achieved good results. 7. Bacterial leaching The bacterial leaching method mainly relies on the redox characteristics and metabolites of the microbial bacteria to reduce or oxidize certain components of the metal mineral, so that the useful minerals are separated from the ore by soluble or precipitated forms, and then chemically or The ore dressing method recovers copper. The mechanism of action of bacteria and copper oxide is as shown in the reaction formula (8) to the reaction formula (10) . Cu 2 O+Fe 2 (SO 4 ) 3 bacteria + H 2 SO 4 → CuSO 4 + FeSO 4 + H 2 O (8) Cu 2 S+Fe 2 (SO 4 ) 3 bacteria → CuSO 4 +FeSO 4 +CuS (9) CuS+Fe 2 (SO 4 ) 3 bacteria → CuSO 4 +FeSO 4 +S (10) Currently 25% of world copper production comes from bacterial heap leaching and underground bacterial leaching. In the United States, about 10% of copper is produced by this method. Among the rocks produced in the US copper mines, 60% of the waste rock contains 0.15% to 0.75% of copper . Most mines in Arizona use bacterial leaching to extract copper from waste rock. Practice has proved that it is profitable to extract copper from waste rock by bacterial heap leaching. In 2000 , Zijin Mining Group built a 300 t/a electric copper scale copper ore bacterial heap leaching-extraction-electrowinning industrial test plant. In 2002 , it expanded to 1000 t/a electric copper. The results show that the bacterial leaching technology is suitable for the development and utilization of Zijinshan Copper Mine. The re-election tailings and flotation tailings of the Baifang Copper Mine of Shuikoushan Mineral Bureau contain copper and uranium . The leaching agent is leached by the pool leaching method for 20 days . The leaching rate of copper and uranium is 80%. the above. The copper-containing leachate was replaced with iron and the product was sponge copper. It has been put into production for more than 130 tons of sponge copper for 7 years . The bacterial Dexing Copper leaching of the annual 2000 t cathode L-SX-EW pilot plant yard area of 7.5 million m3, high stack 80 m, average copper 0.09% waste rock. Spraying began in May 1997 , and in October 1997 , biopile-solvent extraction-electrowinning process was used to produce electric copper with a quality standard of Class A. The Tongguanshan Copper Mine uses a pit water bacterial culture medium to heap leaching of waste ore in the stope. After more than 20 days of leaching, the copper leaching rate is above 80% . M. Oliazadeh et al used microbial technology to recover copper from the furnace dust of a copper smelting furnace. The bacteria used in the experiment were the cultured Thiobacillus, and the influence of the type of the medium and the concentration of the slurry on the copper recovery rate was investigated. When the concentration of the slurry reaches a certain range, increasing the concentration of the slurry may lead to deterioration of the culture process, such as an increase in toxicity, an increase in pressure, and a slow flow of materials. The optimum conditions for the test were: 5% slurry concentration was cultured on mixed medium for 22 d , and copper recovery was 87% . Because biotechnology has the advantages of low cost, low investment, low energy consumption and no pollution to the environment, it has always been considered as a promising new metallurgical technology, and its application prospect is huge. 8. Chlorination roasting - chemical separation Chlorination roasting-chemical separation method, chlorination roasting is the mixing of chlorinating agent ( such as ammonium chloride ) with copper oxide ore raw materials, and the conversion of the target mineral into agglomerated phase metal chloride and material under a certain temperature and atmosphere. The separation of other components, followed by chemical or flotation methods to enrich the mineral of interest. Some people have carried out research on the mixed ore of Cu-calcinated copper ( including CuS , CuO , FeS , CaO , Al 2 O 3 , etc. ) . The results show that when the calcination temperature reaches 327 °C, ammonium chloride is mainly involved in the reaction. When the calcination temperature reaches 327 °C, ammonium chloride is completely decomposed into hydrogen chloride gas and ammonia gas, mainly hydrogen chloride gas participates in the reaction, and the chemical reaction mechanism As shown in the reaction formula (11) to the reaction formula (18) . CuS+4NH 4 Cl=(NH 4 ) 2 CuCl 4 +2NH 3 +H 2 S (11) CuS+2HCl=CuCl 2 +H 2 S (12) FeS+4NH 4 Cl=(NH 4 ) 2 FeCl 4 +2NH 3 +H 2 S (13) FeS+2HCl=FeCl 2 +H 2 S (14) CaO+4NH 4 Cl=(NH 4 ) 2 CaCl 4 +2NH 3 +H 2 O (15) CaO+2HCl=CaCl 2 +H 2 O (16) CuO+4NH 4 Cl=(NH 4 ) 2 CuCl 4 +2NH 3 +H 2 O (17) CuO+2HCl=CuC l2 +H 2 O (18) From the mass loss of the mixture at different temperatures, it is known that NH 4 CuCl 3 , NH 4 FeCl 3 , NH 4 CaCl 3 are formed when the temperature reaches 200 °C . When the temperature exceeds 300 ° C, these compounds decompose into chloride MeCl 2 . If the temperature exceeds a certain value, MeCl 2 reacts in a water vapor environment to form MeO . Different products can be obtained by controlling different temperatures. It is found that the activation energy required for the reaction of copper sulfide with ammonium chloride is 9.5kJ/mol , the reactants are well dispersed, and the stirring is strong. When the temperature is 310~320 °C and calcined for 2 h , the copper sulfide is converted into copper chloride. The conversion rate is 95% . The activation energy required for the reaction of iron sulfide with ammonium chloride is 28.0kJ/mol . The process is controlled by material dispersion and chemical reaction kinetics. When the temperature is 330~340 °C and calcined for 40~50 min , the iron sulfide is converted into chlorination. The conversion rate of ferrous iron is 95% . The activation energy required for the reaction of calcium oxide with ammonium chloride is 56.1 kJ/mol . The chemical reaction kinetics control this process. The temperature rise can accelerate the reaction process. When the temperature is 310~320 °C and the calcination is 40~50 min , the calcium oxide changes. The conversion rate of calcium chloride into calcium is 95% . 9. Special collector for flotation of copper oxide ore For the flotation of copper oxide ore, in addition to the use of xanthate and fatty acid collectors, other special collectors may be used for flotation. 1) Chelating agents, which are mainly used in the production of copper oxide ore effective chelating collectors: B-130 collector, hydroxamic acid ( sodium ) , BJ-60 collector, sulfhydryl benzoimidazole ( referred to as Imidazole ) , ZH collector, 8103 collector, etc. The metal chelate formed by the chelating agent and the metal ion has a smaller solubility product than the general ionic and covalent metal salt, and it has been proved that the chelating agent is more selective as a collector for the copper oxide ore flotation. The traditional vulcanization flotation can only be used for single copper oxide ore, but it is not suitable for mixed ore. When dealing with mixed ore, the low recovery rate of sulfide ore has always been the focus of research. K. Lee et al. used xanthate and hydroxamic acid as collectors to sort the mixed ore. The ore is composed of 70% sulfide ore and 30% oxidized ore. After a rough selection, the recovery rate of copper can be as high as 95.5% . After a selection, the grade of copper concentrate can reach 33.9% , and the recovery rate is 78.5% . Tests have shown that oxonic acid collectors can be used as collectors for mixed ore, that is, for the recovery of sulfide ore and oxidized ore, so as to avoid the loss of sulfide ore. 2) Sulphur-containing non-ionic polar collectors, which mainly include thiazolidine ( ester- 105) , J-622 capture foaming agent, and ethionyl ester (Z-200). Wait. 3) Hydrocarbyl oxyacid salts, which are currently mainly used in the production of sodium dodecyl sulfate and sodium lauryl sulfate. 4) Phosphonic acid collectors, the main varieties used in copper oxide ore flotation are alkyl phosphates and dihydrocarbylphosphonic acids (R2PO2H , R are octyl, sec-octyl, ethyl, cycloethyl , respectively) , phenyl ) . Sinopec Pva 088-03,Sundy Pva 088-03,Polyvinyl Alcohol 088-03,Changchun Pva Bp-03 Saint Petrochemicals Limited , https://www.saintpec.com
4. Segregation - flotation
Wei Huazu used a mixture of malachite and quartz to test the reliability of the vulcanization roasting-flotation process, and concluded that the optimum conditions for calcination ( calcination temperature 650 °C, roasting time 10 min , malachite and quartz ratio 2 : 1) The vulcanized roasting product of the lower malachite may be a chalcopyrite, which provides a theoretical basis for this new process.
October 01, 2024