Copper sulfide flotation concentrates

The improved capabilities of LIX 64 N reagent for recovery, purification, and concentration of copper values from acidic leach liquors were described by DeMent and Merigold (DlO). The leaching of copper sulfide flotation concentrates with subsequent recovery of copper by LIX 64 N was shown to be technically feasible. This extractant loads and strips faster, is more effective in extracting copper from a lower pH solution, has considerably less secondary entrainment, has better iron rejection, and may be used at levels up to 30 vol. % in kerosene without aqueous entrainment. Use of the reagent in operating pilot and commercial plants is also discussed. 

The Dowa Mining Company (K9) in Kosaka, Japan has developed a hydrometallurgical process shown in Fig. 15 to treat 2400 metric tons/ month of copper-zinc sulfide flotation concentrates. The microscopically fine mixture of copper and zinc sulfides was separated from lead sulfide and barite by flotation. The flotation concentrate analyzed 8.7% Cu,... 

The abundance of indium in the earth s cmst is probably about 0.1 ppm, similat to that of silver. It is found in trace amounts in many minerals, particulady in the sulfide ores of zinc and to a lesser extent in association with sulfides of copper, tin, and lead. Indium follows zinc through flotation concentration, and commercial recovery of the metal is achieved by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting and associated lead (qv) and copper (qv) smelting (see Metallurgy, EXTRACTIVE Zinc and zinc alloys). 

Molybdenite [1309-56 ] M0S2, normally floats with the copper sulfides. Therefore, the copper concentrate from the cleaner cells frequently has to be separated from molybdenite in a separate flotation circuit before the copper concentrate goes to the smelter. Gold, silver, selenium, and tellurium are collected with the copper concentrate. 

Tannins are mainly used as depressants for dolomite, calcite and silicate minerals in the flotation of scheelite, apatite, fluorite and copper sulfide. Like starch, tannins after modification by oxidation, sulfidization and aminization (tannin O, S and A, respectively) have been used as a depressant for hematite in the reverse flotation of quartz with oleic acid or dodecylamine as collectors [22]. Flotation results show quartz to be depressed by tannins in the order of tannin A > S at low concentrations of dodecylamine. When an anionic collector is used for the reverse flotation of Ca +-activated quartz with tannins as depressant for hematite, the order of depression is tannin A > O > S. 

Since the compositions of the ores differ widely, the extraction methods vary considerably. An important source is the nickel-copper sulfide of South Africa the ore is physically concentrated by gravitation and flotation, after which it is smelted with lime, coke and sand and bessemerized... 

Although copper metal occurs in the free (elemental) state in some parts of the world, the supply available from such sources is quite insufficient for the world s needs. The majority of the copper used today is obtained from various copper sulfide ores, such as chalcopyrite (CuFeSg), chalcocite (CU2S), and covellite (CuS). Because the copper content of these ores is about 1—2%, the powdered ore is first concentrated by the flotation process. 

HgS was not removed by flotation with SOS at any pH but was removed readily with HTA at acid pH values with a residual mercury concentration of 0.1 mg/L at pH 0.8. Adsorbing colloid flotation of mercury with aluminum or ferric hydroxide and SDS was also ineffective. Flotation of mercury with HTA and FeS at pH 9 yielded residual concentrations of about 0.05-0.07 mg/L (die separation b not aflecled strongly by ionic strength). The most effective separation appeared to be adsorbing colloid flotation with copper sulfide and HTA. Thb method is effective at ionic strengths as high as 2.0, b insensitive to large pH variations, and can yield residual mercury concentmtions of 0.005 m L. 

In the flotation process, cyanide is used to treat the surface of mineral particles for processing in flotation machines. In general, the cyanide solution is used as a depressing agent for pyrite and sphalerite and occasionally for copper sulfides. The cyanide portion of the process constitutes only a small part of the total. Toxic cyanide concentrations can exist from the point of preparation of the solution to its addition into the actual milling process. Once in the milling process, cyanide is reacted... 

The treatments used to recover nickel from its sulfide and lateritic ores differ considerably because of the differing physical characteristics of the two ore types. The sulfide ores, in which the nickel, iron, and copper occur in a physical mixture as distinct minerals, are amenable to initial concentration by mechanical methods, eg, flotation (qv) and magnetic separation (see SEPARATION,MAGNETIC). The lateritic ores are not susceptible to these physical processes of beneficiation, and chemical means must be used to extract the nickel. The nickel concentration processes that have been developed are not as effective for the lateritic ores as for the sulfide ores (see also Metallurgy, extractive Minerals recovery and processing). 

Zinc ores are generally floated at the mine (18). In the case of simple zinc sulfide ores, flotation is carried out by treatment with copper sulfate to activate the sphalerite causing it to be wet by the organic collector (eg, xanthate). The now-hydrophobic zinc ore particles attach themselves to the rising bubbles. Oxidized ore particles present must be sulftdized with sodium sulfide to be floated (19). Flotation produces concentrates which are ca 50—60% zinc. In mixed ore, the lead and copper are usually floated after depressing the sphalerite with cyanide or zinc sulfate. The sphalerite is then activated and floated. 

Hazards of Production. In most zinc mines, zinc is present as the sulfide and coexists with other minerals, especiaHy lead, copper, and cadmium. Therefore, the escape of zinc from mines and mills is accompanied by these other often more toxic materials. Mining and concentrating, usuaHy by flotations, does not present any unusual hazards to personnel. Atmospheric poHution is of Httle consequence at mine sites, but considerable effort is required to flocculate and settle fine ore particles, which would find their way into receiving waters. 

Cadmium occurs primarily as sulfide minerals ia ziac, lead—ziac, and copper—lead—ziac ores. Beneftciation of these minerals, usually by flotation (qv) or heavy-media separation, yields concentrates which are then processed for the recovery of the contained metal values. Cadmium follows the ziac with which it is so closely associated (see Zinc and zinc alloys see also Copper Lead). 

Sulfide Ores ores. In the Zairian ores, cobalt sulfide as carroUite is mixed with chalcopyrite and chalcocite [21112-20-9]. For processing, the ore is finely ground and the sulfides are separated by flotation (qv) using frothers. The resulting products are leached with dilute sulfuric acid to give a copper—cobalt concentrate that is then used as a charge in an electrolytic cell to remove the copper. Because the electrolyte becomes enriched with cobalt, solution from the copper circuit is added to maintain a desirable copper concentration level. After several more steps to remove copper, iron, and aluminum, the solution is treated with milk of lime to precipitate the cobalt as the hydroxide. 

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