专业英语作文

Copper is most commonly present in the earth’s crust as copper-iron-sulfide andcopper sulfide minerals, e.g. chalcopyrite (CuFeS2), chalcocite (Cu2S). The vast majority ofcopper extraction from these minerals is hydrometallurgical. The extractionentails:

(a) concentration

The copper ores being mined are too lean to be smelted directly. Fortunately, the Cu-Fe-S and Cu-S minerals in an ore can be isolated by physical means into high-Cu 'concentrate'. The most effective method of isolating the Cu minerals is froth flotation.

(b) smelting

The objective of the smelting is to oxidize S and Fe from the Cu-Fe-S concentrate to produce a Cu-enriched molten sulfide phase (matte). Example reactions are:

Matte smelting is most often done in flash and submerged tuyerefurnaces . It is carried out to a lesser extent in top lance furnaces (Mitsubishi, Isasmelt), shaft furnaces, reverberatory furnaces, and electric furnaces.

(c) converting

Copper converting is oxygen enriched-air or air oxidation of the molten matte from smelting. It removes Fe and S from the matte to produce crude (99% Cu) molten copper. Converting is mostly carried out in the cylindrical Peirce-Smith converter.

The converting takes place in two sequential stages: the FeS elimination or slag forming stage and the blister copper forming stage

(d) fire- and electrorefining

Electrorefining requires strong, flat thin anodes to interleave with cathodes in the refining cell. These anodes are produced by removing S and 0 from molten converter 'blister' copper then casting the resulting 'fire refined' copper in open, anode shape molds.

The copper from the above processing is electrochemically refined to high purity cathode copper. It is suitable for electrical and all other uses.