Acidic Pretreatment of Hard-to-treat Copper Ore Flotation Middlings to Facilitate Flotation Efficiency
Unique mineralogical and petrological properties of black shale in the copper ore deposit of the Foresudetic Monocline (SW Poland) resulting from three lithological layers have been described in terms of its unfavorable behavior in the ore processing circuits. A concept of processing of a part of the black shale fraction from the flotation circuit of the concentrating plant by separating a by-product enriched in the shale matter was presented. This by-product represents the tailings of the first cleaning flotation and, as a hard-to-treat circulating middlings, overload the cleaning operation in the flotation circuit. It was found that the investigated by-product cannot be effectively upgraded using standard xanthate flotation. This is due to a fine dissemination of sulfide minerals in the dolomitic and clay shale particles significantly enriched in organic carbon. The content of the organic carbon is similar to that in the petrographically pure black shales.After a comprehensive examination of the shale by-product it was recognized that the investigated middlings can be regarded as a specific shale concentrate for individual processing. The effect of non-oxidative leaching of middlings with sulfuric acid on their further flotation was presented. It was shown that non-oxidative leaching is a selective process, in which calcium and magnesium carbonates decomposition leads to effective liberation of sulfide minerals which were freely disseminated in the hydrophilic carbonate gangue. Leaching of the flotation feed with sulfuric acid selectively decomposes carbonate minerals and consequently enhances flotation results. Saturation of leaching slurry with gaseous carbon dioxide favorably creates non-oxidative conditions and leads to a great decrease of the electrochemical potential of sulfide particles as well as hinders their solubilization.Partial carbonates leaching from middlings resulted in evident liberation of valuable minerals.Consequently, it resulted in an increase of both recovery and grade of concentrates obtained by flotation of shale by-product after non-oxidative leaching.
Copper ores Black shale Flotation Non-oxidative leaching
T. Chmielewski A. Luszczkiewicz Z. Konopacka
Division of Chemical Metallurgy, Faculty of Chemistry, Wroclaw University of Technology, Wroclaw, Po Laboratory of Mineral Processing, Institute of Mining Engineering Wroclaw University of Technology,W
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
1189-1200
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）