Separation of dark-colored minerals from feldspar by selective flocculation using starch

Feldspar ores usually contain some amounts of impurity dark-colored minerals (DCM), rich in iron. Such ores must be comminuted for the liberation and separation of the said impurities. Ultra-fine particles which are generated during comminution are difficult to treat by conventional mineral processing methods. It is known that iron minerals have a specific affinity for starch. This phenomenon has been successfully exploited in the selective flocculation and flotation of iron ores. In this study, the possibility of separation of DCM from feldspar by selective flocculation using starch was investigated. It was found that DCM also had a specific affinity for starch. Flocculation tests revealed that DCM alone could be flocculated with starch, while feldspar alone could not. Selective flocculation tests of the mixture of DCM and feldspar indicated that selective separation of DCM from feldspar using starch as a flocculant could be possible. (C) 2004 Elsevier B.V. All rights reserved.