Closed-water circuitry of a coal preparation plant with jig-flotation process
- Datun Coal Preparation Plant, Peixian (China)
Typical flowsheet of coal preparation Plants for metallurgical coal in China is shown in Figure 1: (a) Crushed raw coal, 50{times}0 mm in size, treated in jig circuit, giving reject, middling and overflow; (b) The jig overflow directed to a spitzkasten, in which the granular concentrate settles and is dug up by a dewatering bucket elevator and discharged onto a sizing-dewatering screen; the +13 mm fraction from the screen, together with that of -13+0.5 mm after going through the dewatering centrifuge, contributing the main portion of the plant concentrate; (c) The screen underflow directed back to the spitzkasten, the overflow from which is the main stream of slime water to be treated by a thickener; the clearified overflow is the circulating wash water and its thickened underflow directed to flotation circuit; (d) In the flotation circuit, the froth concentrate is dewatered by vacuum filter and the tailing, after thickened, by press filter; vacuum filtrate directed back to the preceding spitzkaten and the clear filtrate joining with the circulating water. The specific features of such a coal preparation process is its simplicity, both in circuitry and equipment layout, and full treatment of coal down to 0 mm. On the other hand, much problems arise with slime water treatment in that: (a) Large quantity of slime water to be processed, large volume of holding vessels required and consequently large quantity of coal fines kept circulated; (b) Long contact time of fine particles with water, leading to their poorer floatability; (c) Time lag between jig circuit and flotation circuit unavoidable for their normal operation; (d) Closed-water circuit difficult to be maintained, leading to high solid content in circulating water and blackwater discharge.
- OSTI ID:
- 45124
- Report Number(s):
- CONF-930413--
- Country of Publication:
- United States
- Language:
- English
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