| Copper oxide ore is an important component of China’s copper resources, commonly found in oxidation zone of the upper part deposit, and had the characteristics of complex mineral composition, high structure disparities, fine disseminated grain size and high mud content, due to complex formation conditions. Silver was widely distributed in nonferrous metal deposits, especially accompanying and symbiotic in Cu, Pb and Zn deposits, for the characteristic that silver had an affinity for sulfur, copper and iron. In terms of subordinate minerals, the silver in copper mines accounted for25%of the total amount, and in the aspect of production, about25%of silver was produced from associated silver copper mine. Therefore, it had extremely important significance to China’s copper and silver production to strengthen the comprehensive recycling of silver-containing copper ore.Taking the silver-containing copper oxide from Lanping as research object in this paper, the mineralogy research results showed that the copper grade was1.73%, the oxidation rate was90.57%, the combined rate was19.50%and silver grade was164.10g/t, the main ore minerals were malachite and azurite, and the main gangue minerals were dolomite and calcite, accounting for89.20%of mineral content, belonging to carbonate type high oxidation rate refractory copper. The main reclaiming objects were copper and silver, other elements content was so low that there was no recycling value. Copper mainly existed in malachite and azurite in the form of independent minerals, while the copper in gangue mineral may be fine grained disseminated malachite or small inclusion, which was difficult to achieve liberation. Associated silver mainly in the form of isomorphism presented in malachite and azurite, and could be recycled along with copper concentrate. The screening test results showed that the ore was serious sliming, while distribution of copper in various sizes was uniform, so pre-desliming could not be carried out on this copper oxide.Combined with ore properties and present situation of copper oxide processing, finally the sulphidizing flotation process without pre-desilming was adopted, to achieve comprehensive recovery of copper and silver through appropriate fine grinding and intensive flotation. With the principle flow of twice roughing, by exploring the influence of different factors on indicators, the optimal grinding fineness was-0.074mm accounted for88.00%, and the dosage of optimal reagent system were:sodium silicate2000g/t, sodium sulfide2000g/t, ammonium sulfate2000g/t, butyl ammonium aerofloat75g/t, butyl xanthate100g/t, isoamyl xanthate100g/t. On the basis of condition tests and open circuit tests, finally the indicators was obtained that copper concentrate grading copper16.33%, silver1785.65g/t, with recovery of80.33%and92.60%, by the closed circuit test of twice roughing, twice cleaning, triple scavenging.Pilot-scale tests were carried out on the basis of laboratory tests and the grade of copper and silver were respectively1.22%and65.10g/t, decreasing significantly compared with laboratory tests. Oxidation rate decreased to83.62%and the binding rate was22.11%. With the recommended process and reagent system, the verification test results showed that recommended process and reagent system had better adaptability to the ore, but the indicator decreased. Changing grinding fineness-0.074mm accounted for83.10%, the pilot-scale tests process with the recommended process and reagent system was stable and ultimately obtained the indicator that copper concentrate containing copper17.42%, silver986.30g/t, and the corresponding recovery was73.36%and78.47%. |
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