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磷矿分析一般采用盐酸、硝酸、王水或HCIO_4—HNO_3混合酸加热溶矿.有时还用碱高温熔融.Barton用1:1盐酸溶解磷矿,用磷钒钼黄比色方法分析多种磷矿的全磷含量.其测定结果一部分同容量法很接近;另一部分却有不同程度的正或负的误差.其中相对误差有些超过百分之几.正误差可能由于在CI~1存在下铁的干扰;负的误差可能由于1:1盐酸对某些磷矿未能充分溶解.有些文章介绍用硝酸溶矿,在酸的不溶物中还有相当量的磷.特别是含锰较高的磷矿.Allen Gee等用HGIO_4—HNO_3混合酸溶解磷矿.为了除去硝酸及硅的干扰,溶矿时加热半小时至1小时,使硅酸脱水并除去剩余的硝酸.以上采用浓酸溶矿的方法,都因为要除去盐酸或硝酸的干扰或要控制比色时酸量等原因,均需要长时间加热,同时蒸发出来的酸的蒸汽严重污染环境,特别是不能把磷定量地溶解出来,以至带来很大的分析误差.本文发现硝酸铝——柠檬酸混合溶液对磷矿有特效的溶解作用.适量的溶剂与磷矿粉混合微沸3～5分钟,能把磷定量地溶解出来,经选用国内外十种磷矿进行试验,
Phosphorite analysis commonly used hydrochloric acid, nitric acid, aqua regia or HCIO_4-HNO_3 mixed acid heating lysis, sometimes with high temperature melting.Barton dissolved phosphate rock with 1: 1 hydrochloric acid, phosphorous vanadium molybdenum yellow colorimetric analysis of a variety of phosphorus The total phosphorus content of the ore.Its determination results are close to the volumetric method.The other part has some positive or negative errors.The relative errors are more than a few percent.Positive errors may be due to the presence of iron in the presence of CI ~ Negative error may be due to 1: 1 hydrochloric acid for some phosphate rock failed to fully dissolve some articles introduced with nitric acid dissolved ore, there is a considerable amount of phosphorus in the acid insoluble matter, especially with higher manganese Phosphate rock .Allen Gee and other HGIO_4-HNO_3 mixed acid dissolved phosphate .In order to remove the interference of nitric acid and silicon, dissolved in the heating half an hour to 1 hour, the silicic acid dehydration and removal of the remaining nitric acid. Above the use of concentrated acid dissolved ore Method, because of the need to remove the interference of hydrochloric acid or nitric acid or to control the amount of acid colorimetric and other reasons, require a long time to heat, while evaporation of the acid vapor seriously pollute the environment, in particular, can not quantitatively dissolved phosphorus, As a result, great analytical errors are caused. It is found that the mixed solution of aluminum nitrate and citric acid has specific dissolution effect on phosphate rock.A suitable amount of solvent mixed with rock phosphate and slightly boiled for 3 to 5 minutes can dissolve phosphorus quantitatively and selected ten kinds of phosphate rock experimenting,