Problems of Lead and Arsenic Removal from Copper Production in a One Stage Flash-Smelting Process

摘要

Copper content in chalcocite-bornite concentrates of KGHM Polska Miedz S.A. is at the same level as in the chalcopyrite concentrates - 20 to 30 %, however their iron and sulphur content is several times lower, 2 to 7 % and 9 to 12 %, respectively. The additional characteristic feature of the Polish copper concentrates is presence of organic carbon (5 to 8 %) and significant content of impurities, especially Pb (1.5 to 3.0 %) and As (0.05 to 0.4 %).The mentioned above properties, especially low iron and sulphur content, resulted in application of a one stage flash-smelting process in HM Glogow II in 1978. Currently implementation of an analogous technology for HM Glogow I is considered, to replace shaft furnaces where briquettes of copper concentrates are smelted. Because of specific thermodynamic properties of lead and arsenic and their chemical compounds the removal of the impurities from the one stage flash-smelting process requires special technological operations and logistics. Pb and As concentrate in significant volumes in the CuPbFe alloy from electric furnace and in the converter slag. To maintain a specific lead and arsenic level in CuPbFe alloy it is necessary to direct a part or the whole of converter slag mass for separate treatment. Currently a part of the converter slag from HM Glogow II is directed to the electric furnace for copper removal from flash-smelting slag and another part for treatment in shaft furnaces of HM Glogow I. With liquidation of shaft process at HM Glogow I and replacing it with a one stage flash-smelting process the converter slag will have to be treated by some other methods. Both hydro- and pyrometallurgical technologies are considered for the treatment of converter slag. The paper presents a description of lead and arsenic behaviour in the one stage flash-smelting process as well as discussion on the methods for separation of those impurities from copper production cycle.