Copper Anode Slime Extract Selenium, Tellurium Experimental Study

The copper anode slime is copper electrolysis refining by-products produced in the process of smelting, at the same time it is an important raw material for comprehensive recovery of copper smelting enterprises, it has a great influence on the economic benefits of enterprises. Copper anode slime is rich in gold, silver, platinum, palladium and other precious metals and rare metals such as selenium, tellurium, as well as copper, lead, and other base metals. Selenium and tellurium recovery form copper anode slime is an important part of comprehensive recovery of valuable metals.Selenium, tellurium, etc is reviewed in this paper of the physical and chemical properties of metal and the copper anode slime treatment process, the characteristics of different processing technology was introduced in detail and selenium, tellurium extracting process. In view of the status quo of selenium, tellurium recovery rate is low, produced by a copper smelter in yunnan copper anode mud as the experimental research raw material, under the premise that does not affect the recovery rate of gold, silver, adopt pretreatment acid leaching-chlorination process leaching Selenium and tellurium-chloride liquid reduction in addition to gold-sulfur dioxide reduction process of selenium, tellurium extraction in copper anode slime. Chlorination process is mainly studied the direction and distribution of selenium and tellurium, has obtained the good effect.The results show that the chloride leaching of copper slag do the thermodynamics analysis, considered chloride leaching of copper anode slime is better technology of extracted selenium, tellurium, at the same time the experiment to determine the optimized technology of chlorination leaching conditions:150min, temperature60℃, mass concentration of65g/L sodium chlorate, liquid-solid ratio4:1,50g/L sodium chloride concentration, sulfuric acid acidity of300g/L, under the condition, the leaching rate of selenium was96.5%, the leaching rate of tellurium was 76.4%, while leaching rate of gold reached93.7%. The silver content is3.5mg/L in chloride solution, silver trace leaching, shows that effect of recovery rate of silver in the chloride leaching selenium, tellurium is minimal.Studied the content and phase of copper in the copper anode slime, high content of copper can lead to chlorination agent consumption increases in the process of direct chlorination leaching of copper anode slime, thus higher concentration of chloride ions in the leaching liquid do adverse to the subsequent wastewater treatment, the need for copper removal of copper anode slime pretreatment. Proposed to join ferric sulfate in the dilute sulphuric acid solution, by the catalytic oxidation properties of Fe3+ions leaching removal of copper in the copper anode mud, experimental conditions were optimized by response surface method, determined the optimal conditions of removing copper in pretreatment acid leaching of copper anode slime, leaching time of2.4h, acidity of110g/L, the liquid-solid ratio of10:1, under the optimal condition, the leaching rate of copper of actual measured is96.52%. By comparing the XRD before and after the pretreatment,the result shows that pretreatment acid leaching of copper anode mud do not change the phase of selenium. Also detected in the leaching liquid does not contain selenium, tellurium, gold, silver, and the chemical analysis results show that the pretreatment will not produce great influence of tellurium extraction, which can add pretreatment before extraction of selenium, tellurium by chloride acid leaching process, as to achieve the enrichment of selenium, tellurium, etc rare metals.In order not to affect the gold recovery rate in the process of recycling Selenium and tellurium, need to remove the gold in chloride solution, using FeSO4to reducing precipitation of the gold chloride acid, the temperature of80℃,90min, the amount of ferrous sulfate for theory under the condition of10times,the amount of reduction rate of99.7%, after reducing fluid the gold content is less than1mg/L, at the same time, the reduction rate of selenium, tellurium is only3.8%and3.8%, achieve better effect to remove gold in chloride liquid, XRD result shows the slag from precipitation for high grade gold, which has no elemental characteristic peak of selenium and tellurium, less impurities. Calculated and analyzed the distribution of selenium,tellurium,etc in copper anode slime chlorination process.selenium and tellurium mainly distributed in liquid after reduction, respectively92.8%and73.6%of the total, and selenium in the chloride slag and precipitation slag of3.5%and3.7%respectively, tellurium in the chloride slag and precipitation slag of23.6%and2.8%respectively. At the same time, this paper discusses the comprehensive recovery technology of selenium, tellurium, etc, compared with the traditional mineral processing and metallurgy process technology, direct recovery index has been increased greatly.