Recovery of molybdenum and rhenium using selective precipitation method from molybdenite roasting dust in alkali leaching solution

A study has been conducted for the separate recovery of molybdenum and rhenium from alkali leaching solution of molybdenite roasting dust by a selective precipitation method. Two kinds of synthetic alkali leaching solutions were employed and more than 85% of molybdenum was recovered as a precipitate in the experimental conditions of 243.15K, pH 2.2, 200 rpm of agitation speed, 7,200s of reaction time, and 1.5 of equivalence ratio between NH ₄OH and NaOH for NaOH leaching solution. Regarding NH ₄OH leaching solution, the optimal conditions for the formation of molybdenum precipitate were found to be 243.15K, pH 2.5, 100 rpm of agitation speed, and 18,000s of reaction time. The precipitation efficiency of molybdenum was higher than 99% in these conditions and molybdenum was observed to be precipitated as ammonium molybdate. Contrary to the precipitating behavior of molybdenum, rhenium was precipitated very little in the given conditions, which suggested a possibility for the selective recovery of molybdenum and rhenium.