Takaaki Hatano, Toshiaki Yano,Masahiro Tsuji and Tsugio Ogura
Nippon Mining & Metals Co., Ltd., Kurami
In order to search for a desulfurizing method for molten copper and copper alloys in the remelting process, oxidizing desulfurization by oxygen gas or oxidizing flux and reducing desulfurization by magnesium or basic fluxes (CaO or BaO, Na2CO3 system) were studied with molten Cu-8%Sn-0.1%P alloy.
In oxidizing desulfurization, a considerable loss in copper, tin and phosphorus took place. Desulfurizing effect by magnesium was small. Desulfurization reaction was not observed in addition of CaO only, while it proceeded by co-operative effects of the addition of CaO sintered with CaF2 and strong stirring. Using CaO-NaCl fluxes desulfurization took place rapidly. In CaO-Na2CO3 fluxes, the degree of desulfurization was determined by the quantity of Na2CO3, and CaO had a suppressing effect of sulfur reversion. BaO-BaF2 fluxes showed the highest ability of desulfurization, and the rate of desulfurization increased with increasing BaF2 content or with stirring. In the treatment by using the basic fluxes, no losses of copper and tin were found, a certain amount of phosphorus, however, was lost after the treatment.
(Received August 4, 1994)
desulfurization, copper alloy, oxygen gas blowing, magnesium addition, oxidizing flux, basic flux
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