Process for the recovery of valuable metals, particularly rare earths and similar metals, from a carbonate-containing raw material

摘要

Process for the recovery of valuable metals, particularly rare earths and similar metals, which occur in a finely distributed condition in a raw material containing calcium carbonate.PPThe raw material with the valuable elements is subjected to vigorous heating to decompose calcium carbonate and is allowed to react with sulphur oxides, particularly SO.sub.2, so that the calcium present is converted to insoluble calcium sulphate. The valuable metals are extracted from the calcine by extraction with dilute acid or water, whereafter the valuable metals are recovered from the extract in a per se known manner.P PThe heating and the reaction with sulphur oxides may be carried out by mixing the raw material containing the valuable elements with sulphur or a combustible sulphurous material, such as pyrite, and subjecting it to exothermic combustion.