Coal Preparation Techniques
There are widely regions and plentiful coal sources in China, and there are all kinds of coal, quality of coal changes largely. Coal processability is belong to difficultly separation and extreme difficultly separation degree. Therefore, various kinds of coal preparation techniques are used in China, mainly including jig, dense medium, flotation and dry coal preparation.
Jig technique has many advantages of large adaptability to difference quality coal, simple and credible system, low production cost, separation effect well etc. it has been being main coal preparation techniques for long time. At present, the proportion of jig separation application in plants is about 60% in China.
With the development of mine modern and civilization production, basket sieve jig is gradually applied in coal preparation plants in recent years, replaces operator to remove gangue.
Dense medium technique has gradually mature through production practice and research in a few tens years, especially dense medium cyclone which has got greatly progress. It mainly owes to application of wearable material, which prolongs use life-span of facilities and pipelines, and improvement of density automatic control level, which makes operation simply and reduces medium consumption in the same time. Because invest and production cost of dense medium has been close to jig, and with the increasing of demand for clean coal products, coal processability degree becomes difficulty, dense medium separation techniques gets widely applying in recent years. It may replace jig and become main coal preparation techniques in China.
The development of flotation techniques is quick in China, but in application, only coal preparation plants of coking coal and coal preparation plants of anthracite jetting into blast furnace use flotation.
Dry separation (including fluidization bed coal preparation and wind separation) is used in some regions of cold west and water sources shorten and coal easy to slime in China. There are a few plants, and they mainly use wind separation.
Shaking table separation, spiral separation, self-production medium spiral drum separation and hydro-cyclone separation are applied in some small plants in China.
Magnetic separation, electric separation, X-ray separation, micro-wave separation, chemical separation and bio-separation still are in course of research and test.
Technical schemes in common use
Due to quality of coal, types of coal, plant model, market, environment and history, technical schemes which coal preparation plants are using are as following:
Above 0.5 mm coal is separated by jig, dense medium, or combination jig with dense medium separation.
Below 0.5 mm fine coal is separated by flotation or slime dense medium.
Over size block coal is separated by hand removal or shaking sieve separation or dense medium separation.