Main Functions of Phosphorite
Phosphorus is an important component of biological cytoplasmic elements. It is also essential to growth of the plant. 84% ~ 90% phosphorite in the world is used for the production of various phosphates, 3.3% for that of feed additives, 4% for that of detergents, and the rest for the chemical industry, light industry, national defense and other industries. In China, phosphate fertilizer takes 71%, phosphorus 7%, phosphate 6%, phosphide 16% in phosphate fertilizer consumption structure. Phosphate fertilizer plays an important role in crop production. There are many different types of phosphate fertilizers. In our country, phosphate fertilizer products are mainly superphosphate, calcium magnesium phosphate, deoxy-phosphate, as well as re-superphosphate, ammonium phosphate and potassium dihydrogen phosphate, such as high efficiency compound fertilizer. Phosphate is also an important chemical raw material mineral. Parts of phosphate rock are used in the preparation of pure phosphorus (yellow, red), and chemical raw materials, a small amount for animal feeding. Fluorapatite crystals are ideal laser emission materials, phosphate glass laser has been applied. |
Quality demand of industrial process to phosphorite
There are three kinds of processing methods for phosphorite, namely mechanical, acid and thermal processing method. And acid processing method is mainly used at home and abroad.
1.Mechanical processing: to grind the phosphate rock stone into powder, and directly used for acidic soil and fertilizer.
2.Acid processing: the main products gained from decomposition of phosphate rock powder by inorganic acid are water-soluble phosphate fertilizer and phosphate. The main products are: superphosphate, extraction phosphoric acid, re-superphosphate, ammonium nitrate, phosphate and so on. Phosphate rock P2O5 should ¡Ư 28% when manufacturing these phosphate fertilizers.
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3. Thermal processing:
to produce calcium magnesium phosphate by mixing phosphate rock, silica and magnesian ore in appropriate proportion, melting them in blast furnace or electric furnace at high temperature and water quenching, etc.
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Mining and Processing of Surphur Deposit
China began its research on phosphate beneficiation in the late 50s of 20th century, and in 1958 a large-scale sedimentary metamorphic phosphorites flotation plant dealing with 1,200,000 t ore in the first year--Jiangsu Jinping Phosphorite concentration plant was built and put into production. Hereafter, Hebei Maying Phosphorite Plant was built and put into production with an annual 300,000 t ores handling capacity. The building up of the two plants marked that China has mastered the phosphate beneficiation technology. At present, the direct flotation, anti-flotation, scrub Desliming, heavy-medium separation has been applied to industrial production.
1.Floatation Method£º Phosphate rock in China generally contains higher MgO. In China floatation technology is used most frequently to separate phosphate rock. Floatation technologies include direct flotation, anti-flotation and double reverse flotation flotation technologies. Direct flotation technology and anti-flotation technology are used more in production practice. Direct flotation technology, it takes effective inhibitors to inhibit gangue minerals of phosphorite, and enrich phosphate into flotation foam by collector. The technology has been successfully applied to industrial production of apatite-type magmatic rocks and sedimentary phosphorites metamorphic ore. Jiangsu jinping concentrator phosphate plant is a typical example. Sedimentary type calcium (Ca Si) quality phosphorite are recognized as the phosphate ore most difficult to separate. But since the "S" series of inhibitors has been developed, a breakthrough has been made in such phosphorite ore beneficiation technology. Anti-flotation technology, anti-floatation technology is mainly used for the separation of phosphate rock and dolomite, taking inorganic acid as a adjust agent of pH value, in weak acid medium with fatty acid collector floating dolomite, phosphate rock materials will be enriched in Products within the trough. The biggest advantage is its implementation of the ambient temperature flotation, coarse grain size slot in favor of Products Products after treatment. The process has been successfully used in industrial production of Wengfu phosphorite sedimentary phosphate rock.
2.Scrubbing and Desliming Technology£º China has began its research on scrubbing and desliming Hunan Liuyang Phosphorite in mid-60s, and has got certain positive results. At present, the technology has been successfully developed and applied to the production of phosphate rock in Dianchi region. The principle of the technology is simple, and it is purely physical beneficiation, namely to scrub or grind phosphate rock in the water to remove the surface of muddy material and enrich phosphate. Enrichment of the process is not high, only improving P2O5 grade from 3 to 5 percentage points. In 1995, Jinning Phosphate Scrubbing Plant has been built and put into production.
3.Heavy Medium Separation Technology: Difference between the proportion of minerals is the key in heavy-medium separation. China begins its research in mid-80s, finding that the key lies in whether the separation proportion can be strictly controlled at between 2.8 ~ 2.9. In 1992, Hubei Yichang phosphate heavy-medium flower fruit processing plant which adopted this technology was founded and put into production. Heavy-medium separation technology is of high separation efficiency, less pollution, etc., and thus has broad developing prospect. In the long run, this technology can be used as a pre-operation, eliminating from low-grade phosphate rock, thereby enhancing the follow-up sorting results.
4.Roasting Assimilation Technology£ºThis is a chemical beneficiation method, mainly used for silicate minerals with rare carbonate-based phosphate rock. It makes use of the principle that carbonate minerals give off CO2, then when water added CaO, MgO hydration hydrate into fine-grained Ca (OH) 2 and Mg (OH) 2, adopting a classification technique after removal of calcium and magnesium hydroxide to enrich phosphorus minerals. The sorting process has got good results in sorting Ho Yan Shaanxi, Guizhou Wengfu, Datang and has completed the extension of the trial. However, because it has high energy consumption, the milk of lime pulled away is difficult to treat and the production is not easy to control, it has not yet been widely applied.
5.Chemical beneficiation: This method is mainly used to exclude carbonate minerals, especially MgO. It can reduce MgO content to below 0.5%. Because of higher processing cost, it is considered only when other technologies fail to meet the demand of later process. At the chemical beneficiation of phosphate rock, the extracting agent used are mainly ammonium chloride, sulfuric acid and sulfur dioxide, etc. Sulfate is the most widely used one.
6.Photoelectricity Assorting Technology: Photoelectricity Assorting makes use of different color shading between ores and gangues to separate the ore. It is rarely used in the production of phosphorite. |
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