METHOD FOR FINE DECOPPERIZATION OF LEAD

摘要

nonferrous metallurgy. SUBSTANCE: sodium hydroxide is admixed to molten lead at 340-370 C in proportion 0.2-0.3% of the weight of lead. Thereafter, 0.03-0.06% sodium sulfide and simultaneously 0.05-0.1% elementary sulfur are introduced into funnel formed on the surface of stirred melt to give double copper-sodium sulfide having lower solubility in liquid lead than sodium sulfide. The latter emerges on the surface of metal and is removed after each portion of sulfur-containing reagents admixed to melt. Sulfur-containing reagents are added 1 to 4 times depending on content of copper in initial material. Residual content of copper in lead is equal to or below 0.001%. EFFECT: provided fine decopperization of lead within sufficiently wide temperature range in melt containing no tin and silver. 1 tbl