Pb-Fe-As, Pb-Cu, As 3元系における2液相分離範囲と銀の分配

鉛溶錬スパイスに関する基礎的研究 (第1報)

抄録

In nonferrous metallurgy such as copper, nickel and lead smelting, occasionally speiss is formed because of arsenic or antimony contained in ore. Pb-Fe-As and Pb-Cu-As ternary systems are regarded as the most fundamental systems of speiss which occured in lead smelting. The miscibility gap and the distribution of silver between molten lead and speiss in these two systems have been determined by quenching method between 900°C and 1200°C.
In Pb-Fe-As system, the miscibility gap at 1000°C and 1200°C covers a wide composition range under 50 percent arsenic in speiss. Its temperature dependence could not be observed within the experimental error. The dissolution of lead in speiss remains at a constant value of about 3 percent up to 40 percent arsenic in speiss.
In Pb-Cu-As system the miscibility gap in Pb-Cu binary system is widened by addition of arsenic, and at 1000°C, lead dissolves into speiss nearly 11 percent at the composition of speiss about 19 percent arsenic which is equilibrated with metallic lead containing 2.5 percent of copper. When the arsenic content in speiss exceeds this composition, the miscibility gap drastically becomes narrower.
The distribution coefficient of silver between metallic lead and speiss K_Ag, defined by K_Ag= wt%Ag in speiss/ wt%Ag in metallic lead, increases from 0.02 to 0.4 when the arsenic content in speiss increases from 1 to 51 percent in Pb-Fe-As system. Specially, in the composition range over 40 percent arsenic in speiss, the increase of K_Ag is quite remarkable. On the contrary the value of K_Ag shows about unity in Pb-Cu-As system.