Abstract: In order to recover valuable metals from copper smelting dust,properties analysis were carried out on the dust of high copper and high arsenic produced by a copper smelter,and the occurrence state and content of main elements in the dust were determined.The results showed that copper and zinc mainly existed in the form of sulfate and oxide,while arsenic mainly existed in the form of oxide,which has good leaching characteristics.The copper in dust was recovered by low concentration acid leaching-sulfide precipitation method,and the effect of flocculant on settling property of sulfide pulp was investigated.The results showed that:① under the conditions of initial sulfuric acid concentration of 40 g/L,leaching temperature of 50 ℃,leaching time of 90 min,liquid-solid mass ratio of 4∶1 mL/g,the leaching rates of copper,zinc and arsenic were 96.33%,96.52% and 83.72%,respectively.② Under the conditions of sodium sulfide excess coefficient of 1.3,pH value of 3.0 and reaction time of 20 min,the copper precipitation rate could reach 99.99%.The main phase of sulfide precipitation products was CuS,and the grade of copper was 56.90%,which could be directly used in industrial production.After precipitating copper,the solution could continue to recover valuable metals such as Zn.③ The addition of flocculant could increase the size of sulfide precipitate,accelerate the settlement of pulp and facilitate solid-liquid separation.

Key words: copper smelting dust,acid leaching,sulfide precipitation,copper sulfide,flocculant