Bennett等提出了用聚环氧乙烷(PEO)凝聚重量法测定矿石中二氧化硅:将含硅酸的盐酸溶液蒸至胶状,加入PEO凝聚沉淀硅酸,滤液中残留硅酸为含硅量的1.5～2.0%。本实验对Bennett法作了改进。拟订了氢氧化钾-碳酸钠在石墨坩埚中熔样,浓硝酸提取,用PEO凝聚沉淀硅酸的重量法。方法较原法快速,结果准确,稳定。此外,由于滤液为硝酸介质,以高锰酸盐光度法测定锰时,无须驱赶盐酸。实验部分 1 聚环氧乙烷(PEO):0.5%,称取PEO0.5克,加水100毫升,浸泡4～6小时,搅拌使其完全溶解。 2 操作手续 Bennett et al proposed polyethylene oxide (PEO) agglomeration gravimetric determination of silicon dioxide in ore: hydrochloric acid solution containing silicic acid steamed to a colloid, adding PEO coagulated precipitated silicic acid, the filtrate was residual silicic acid containing silicon The amount of 1.5 to 2.0%. Bennett method has been improved in this experiment. Potassium hydroxide - sodium carbonate prepared in the graphite crucible melting, concentrated nitric acid extraction, precipitation of silicic acid with PEO gravimetric method. The method is faster than the original method, the result is accurate and stable. In addition, since the filtrate is nitric acid medium, the determination of manganese by permanganate spectrophotometry does not eliminate hydrochloric acid. Experimental part 1 polyethylene oxide (PEO): 0.5%, weighed PEO0.5 grams, add water 100 ml, soak for 4 to 6 hours, stirring to completely dissolve. 2 procedures