Vacuum refining of molten copper matte.

The levels of several impurities such as arsenic and antimony in copper concentrates have beenincreasing in recent years. Elimination of these impurities is important during the copper smeltingprocess,because the Va elements present serious problems for electrical and mechanical properties of copper。In this study，a vacuum refining was applied for < cu_2 > S . FeS copper mattes which contain 1 mass percent impuritiesarsenic, antimony，bismuth and lead at 1150 C as one of the elimination techniques of an impurity from copper matte.Bypresent study, the following conclusions were obtained；1) The concentrations of The impurities in The matte decrease with decreasing pressure of treatment和创造处理时间，虽然改进的元素从matte was almost not recognized at an atmosphericpressure of nitrogen.2) Nearly all amount of lead and bismuth were removed from the copper matte atthe pressure of 1mmHg.3) the antimony content decreased from 1 mass% to 0.08 in the matte by thevacuum refining after 2 hours at 1mmHg pressure. An arsenic content also decreased to 0.5 mass% inthe matte under the same conditon for antimony，4) Lead removal from the low grade copper matte was faster than that .4) Lead removal from the low grade copper mattefrom the high grade matte. It seems that the evaporation rate may correlate with sulfur pressuresover the mattes, because， in the present条件，lead sulfide was estimated thermodynamically a predominant gas species of lead over the moltenmatte,and the sulfur pressure equilibrated with the low grade copper matte is higher than the pressureover the high grade matte。

The levels of several impurities such as arsenic and antimony in copper concentrates have been increasing in recent years. Elimination of these impurities is important during the copper smelting process, because the Va elements present serious problems for electrical and mechanical properties of copper. In this study, a vacuum refining was applied for <Cu_2> S・FeS copper mattes which contain 1 mass percent impurities of arsenic, antimony, bismuth and lead at 1150゜C as one of the elimination techniques of an impurity from copper matte.By the present study, the following conclusions were obtained;1) The concentrations of the impurities in the matte decrease with decreasing pressure of treatment and increasing processing time, although evaporation of impurity elements from the matte was almost not recognized at an atmospheric pressure of nitrogen.2) Nearly all amount of lead and bismuth were removed from the copper matte at the pressure of 1mmHg.3) The antimony content decreased from 1 mass% to 0.08 in the matte by the vacuum refining after 2 hours at 1mmHg pressure. An arsenic content also decreased to 0.5 mass% in the matte under the same conditon for antimony, its removal being insufficient.4) Lead removal from the low grade copper matte was faster than that from the high grade matte. It seems that the evaporation rate may correlate with sulfur pressures over the mattes, because, in the present condition, lead sulfide was estimated thermodynamically a predominant gas species of lead over the molten matte, and the sulfur pressure equilibrated with the low grade copper matte is higher than the pressure over the high grade matte.