Copper oxide and its mixed ore flotation process

In the natural world, sulfide minerals are formed by the action of oxygen in water or water and ions in water to form oxidized minerals. The oxidation process usually takes place in the upper part of the deposit. The thickness of the oxide layer can reach 10 to 50 m depending on the geological conditions. Ore by oxidation rate (percentages refer to a metal oxide minerals present state) may be different from the ore into oxide ores, and sulfide ore mixed mineral. Generally, the oxidation rate is more than 30% for oxidized ore, and the oxidation rate is below 10% for sulfide ore, which is a mixed ore between the two. The main non-ferrous mineral oxide ores of copper oxide, lead oxide and zinc oxide ore.

The non-ferrous metal oxidized ore has the following characteristics: 1The structure is more complicated, the dip-dyed particle size is finer, it is not easy to dissociate, it is generally brittle, and it is easy to be muddy when fine grinding; 2The mineral composition is very complicated, and the same deposit often contains multiple oxidations of the same metal. Minerals, but the difference in floatability is very large; 3 often contains a large amount of slime and soluble salts; 4 the oxidized ore properties of different deposits vary greatly, and even the oxidation degree and ore properties of different sections in the same deposit vary greatly. Therefore, the flotation of oxidized ore is more difficult.

Flotation of copper oxide ore and its mixed ore

The main main copper oxide minerals are: malachite (CuCO3·Cu(OH)2), containing 57.4% copper, density 4g/cm3, hardness 4); azurite (azurite, 2CUCO3·Cu(OH)2) , containing 55.2% copper, density 4g/cm3, hardness 4). Followed by: cyanite (CuSiO3 · 2H2O, containing copper 36.2%, density 2 ~ 2.2g / cm3, hardness 2 ~ 4) and cuprite (Cu2O, containing 88.8% copper, density 5.8 ~ 6.2g / cm3, hardness 3.5 to 4).

Fatty acid collectors have good trapping properties for non-ferrous metal oxide minerals, but due to poor selectivity (especially when the gangue is a carbonate mineral), the concentrate grade is not easily improved. Among the xanthate collectors, only high-grade xanthate has a certain catching effect on non-ferrous metal oxide minerals. However, without vulcanization, flotation of copper oxide ore directly with xanthate has not been applied in the industry due to high cost. The methods that have been applied in practice are:

1 vulcanization method - the most common, simple process, any copper oxide ore that can be vulcanized can be floated by this method. The oxidized ore after vulcanization has the property of sulfide ore and can be floated with xanthate. Malachite and azurite are easily sulfided with sodium sulfide, while chrysocolla and cuprite are more difficult to vulcanize.

The amount of sodium sulfide during vulcanization can reach 1~2kg/(t ore). Since the vulcanizing agent such as sodium sulfide is easily oxidized, the action time is short, and the formed vulcanized film is not stable, and the stirring is easy to fall off, so it should be added in batches, and it is directly added to the first tank of the flotation machine without pre-stirring. When vulcanizing, the lower the pH of the slurry, the faster the vulcanization.

When there are many slime and need to be dispersed, a dispersing agent should be added, usually with water glass. Collectors are generally mixed with butyl xanthate or with black medicine. The pH of the pulp is usually kept at about 9, and when it is too low, lime can be added in an appropriate amount.

2 organic acid flotation method - organic acids and their soaps can be well floated malachite and azurite. This method can be used when the gangue mineral is not a carbonate mineral. Otherwise, the flotation will be deactivated. When a large amount of gangue contains buoyant iron, manganese minerals, will have the same effect, that the flotation is deteriorated. When an organic acid with a flotation collector, usually also sodium carbonate, sodium silicate, phosphate inhibitor as gangue and the slurry adjusting agent.

There are also examples of mixed application of vulcanization and organic acid flotation. Sodium sulfide and xanthate are used to float copper sulfide and partial copper oxide, and then the residual copper oxide is floated with organic acids.

3 Leaching-precipitation-flotation method--Use when both the vulcanization method and the organic acid method cannot obtain satisfactory results. The method utilizes copper oxide minerals to dissolve relatively easily, and the oxidized ore is first leached with sulfuric acid, then replaced with iron powder, and precipitated metal copper, and the precipitated copper is floated by flotation. The method should first be ground to the monomer according to the particle size of the mineral inlay, (-200 mesh accounts for 40% to 80%). The leachate is a 0.5% to 3% dilute sulfuric acid solution, and the amount of acid varies with the ore property of 2.3 to 45 kg / (t ore). For difficult-to-lead ore, tempering can be carried out by heating (45-70 ° C). Flotation is carried out in an acidic medium, and the collector is treated with cresol black or double xanthate. The undissolved copper sulfide mineral and the precipitated metal copper float together and enter the flotation concentrate.

4 ammonia leaching - sulfide precipitation - flotation method - such as the ore contains a large amount of alkaline gangue, the use of acid leaching is large, the cost is too high. The method finely grinds the ore, adds sulfur powder, and then ammonia leaching. During the leaching process, the copper ions in the copper oxide ore react with NH3 and CO2, and are precipitated by sulfur ions to become new copper sulfide particles. The ammonia is evaporated and recovered, and the copper sulfide is floated. The pulp pH is 6.5-7.5, and a good index can be obtained by using the flotation agent of the general copper sulfide ore. This method should pay attention to the recovery of ammonia, otherwise it will cause environmental pollution.

⑤ segregation - flotation --- essence is suitable ore particle size with 2% to 3% of the coal powder, 1% to 2% of the salt mixture, chlorination reduction roasting between 700 ~ 800 ℃, generating Cu The chloride, which is volatilized from the ore, is reduced to metallic copper in the furnace and adsorbed on the coal particles, and then separated from the gangue by flotation. This method is suitable for the treatment of refractory copper oxide ore, especially the refractory copper oxide ore with more mud, combined with copper accounting for more than 30% of total copper, and ore containing a large amount of chrysocolla and copper. When comprehensively recovering gold, silver and other rare metals, the separation method is superior to the leaching-flotation method. The disadvantage is that the heat energy is large and the cost is high.

6 Flotation of mixed copper ore—The flotation process of mixed copper ore should be determined according to the test. The process of simultaneous flotation of oxidized minerals and sulfide minerals after vulcanization can be used. Then select the process of oxidizing minerals. At the same time, the process conditions of flotation of copper oxide minerals and copper sulfide minerals are basically the same as those of flotation oxidized minerals, but the amount of sodium sulfide and collector should be reduced correspondingly with the decrease of oxide content in the ore.

Foreign copper oxide ore uses two processes: vulcanization flotation and acid leaching-precipitation-flotation.