PROCESSING OF HARD-TO-TREAD COPPER ORE AND FLOTATION MIDDLINGS USING CHEMICAL TREATMENT

摘要

An innovative idea of upgrading hard-to-treat sedimentary copper ores technology, comprisingrnflotation combined with acidic non-oxidative leaching has been presented. The acidic leachingrnguarantees effective chemical liberation of copper sulfide particles finely disseminated in a carbonaterngangue of the flotation feed.rnIn the late nineties of 20th century comprehensive studies and investigations have been performedrnon application of chemical pretreatment of hard-to-treat flotation by-products with sulfuric acid.rnFor this purpose a part of the clay-carbonate feed material was separated from the flotation circuitrnand subjected to acidic leaching prior to further flotation. The untreated feed is practically nonupgradeablernby standard procedures due to a very fine mineralisation and severe problems inrnliberation of copper-bearing sulfides. The feed suspension, after non-oxidative leaching, was returnedrnto the flotation circuit in order to separate freshly precipitated gypsum and was finally subjected torncleaning flotation.rnThe combined leaching-flotation process was eventually successfully applied on the industrial scale.rnIn this paper a flotation circuit with acidic leaching of the feed was presented. Flotation indices of thernchemically modified feed were compared with the standard system without chemical pretreatment.rnAfter several months of operation of the new technological system, a significant increase of copperrnand other metals recovery was observed along with an increase in concentrate grade.rnOn the basis of technological experience and additional laboratory investigations application andrndevelopment of proposed chemical pretreatment and further full hydrometallurgical processing ofrnflotation concentrates for improving metals recovery is considered