<報文>塩化による粗銅の精製について

概要

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Removal of various impurities from the liquid crude copper using chloride has been studied thermodynamically and experimentally. Taking account of the free energy of formation of chlorides and the activity coefficients of various impurities, it was estimated that lead, zinc, iron and bismuth may by volatilized by chlorination reaction without any serious loss of copper metal. In the preliminary melting experiment, sodium chloride did not show any effective reaction with impurities, but substantial removal of lead, oxygen and sulfur has been observed by addition of calcium, magnesium and ammonium chlorides. Calcium chloride is especially interesting because arsenic and antimony have also been eliminated probably in the forms of calcium arsenate and antimonate. Silver, gold, nickel and selenium were not removed by chlorination reaction. The crude copper containing higher sulfur and lower oxygen was unconvenient for removal of impurities. The removal reaction was rapid enough and its temperature dependence could not be observed. When lead and oxygen are only elements to be removed, ammonium chloride seems to be attractive, because it becomes effective gaseous reagent by preheating. A typical example of refining of the crude copper by addition of calcium chloride is as following table : [table]
東北大学の論文
1972-03-25