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前言在沉积型磷酸盐矿石中存在的所有杂质中,镁一直被认为是特别能引起麻烦的金属,已研究和设计了一些排除镁的工艺,主要有:·用SO_2进行酸化或用酸浸法排除镁(Anon,1972)。·在磷酸的生产过程中使镁形成不溶性的磷酸镁,以渣的形式将它排除(Anon,1986a)。·用适宜的捕收剂从磷灰石中浮选白云石和碳酸盐,或用正磷酸抑制磷酸盐,然后用合成脂肪酸浮选白云石(Ratobylskaya等,1975)。·用重介质分选法选别粗粒级的白云石,将沉品进行细磨后用浮选法从白云石中选出磷酸盐,所用的捕收剂是脂肪酸、NH_3和燃料油(Lawver等,1978,1980;Snow,1979)。
Introduction Magnesium has long been considered to be a particularly troublesome metal among all the impurities present in sedimentary phosphate ores. Some techniques have been studied and designed to eliminate magnesium, mainly: • Acidification with SO 2 or acid leaching Exclusion of magnesium (Anon, 1972). • Magnesium forms insoluble magnesium phosphate in the production of phosphoric acid and rejects it as slag (Anon, 1986a). Dolomite and carbonate are flotated from apatite with suitable collectors or phosphate is inhibited with orthophosphoric acid and then dolomite is flotated with synthetic fatty acids (Ratobylskaya et al., 1975). · Selection of coarse-grained dolomite by heavy-medium sorting, fine-grinding of the settled product, and selection of phosphate from dolomite by flotation using fatty acids, NH 3 and fuel oil (Lawver 1978, 1980; Snow, 1979).