ISO 1620:1976 天然和人造冰晶石.二氧化硅含量的测定.还原硅钼酸盐分光光度法

标准编号：ISO 1620:1976

中文名称：天然和人造冰晶石.二氧化硅含量的测定.还原硅钼酸盐分光光度法

英文名称：Cryolite, natural and artificial — Determination of silica content — Reduced molybdosilicate spectrophotometric method

发布日期：1976-09

标准范围

规定了氟化钠/三氟化铝摩尔比约为3至1.7的天然和合成材料的试验方法。该方法适用于五氧化二磷含量不超过0.02%（m/m）的产品。该程序包括通过碳酸钠和硼酸的混合物对试验部分进行碱熔。在过量硝酸中溶解熔融物质，使pH值在0,7和0,9之间。在明确规定的酸度、温度、时间和试剂浓度条件下形成（黄色）氧化硅钼酸盐。在酒石酸存在下的选择性还原和在约815nm波长下的测量。

Specifies methods of test for natural and synthetic materials having a molar ratio sodium fluoride/aluminium trifluoride between 3 and 1,7 approximately. The method is applicable to products the phosphorus pentoxide content of which does not exceed 0,02 % (m/m). The procedure consists in alkaline fusion of a test portion by means of a mixture of sodium carbonate and boric acid. Dissolution of the fused mass in excess nitric acid so that the pH value is between 0,7 and 0,9. Formation of the (Yellow) oxidized molybdosilicate under clearly defined conditions of acidity, temperature, time and concentration of reagents. Selective reduction in the presence of tartaric acid and measurement at a wvelength of about 815 nm.

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