水玻璃旧砂中醋酸盐含量分析方法

Analysis method of acetate content in used water glass sands

针对水玻璃旧砂的成分特点,研究了旧砂中的碳酸根、硅酸根等阴离子的影响.结果表明:酸化处理后碳酸根的影响可以忽略;当硅酸根质量浓度高于300μg/mL时,测试结果明显偏高;通过加入MgCl2可沉淀去除大部分碳酸盐和硅酸盐,其中硅酸根的质量浓度可降低到257.6μg/mL以下,将其影响减少到合理范围.据此提出了沉淀分离、索氏提取、酸化后滴定分析的水玻璃旧砂醋酸盐含量方法.采用该方法测定了模拟旧砂样品及工厂实际砂样中的醋酸盐含量,测试结果与离子色谱法的结果相比仅高出0.33%,说明与实际值一致,相对标准偏差低于3%.

On the basis of properties of chemical composition of the used sodium silicate sands,the influence of carbonate and silicate ions was investigated.Results show that the effect of carbonates treated by acidizing the samples can be ignored,and values measured are higher when the mass concentration of silicate ions in samples does not exceed 300μg/mL;most carbonates and silicates can be precipitated and removed by adding MgCl2 into the sample,the mass concentration of silicates can be reduced to below 257.6μg/mL,and its influence can be reduced to a reasonable extent.An approach for analyzing the content of acetate in used sodium silicate sands was proposed,which includes following processes as participation separating,Soxhlet extracting,acidizing and titrating.The content of acetate in the simulated samples and actual samples taken from a factory were measured by using the method,and the test values are only 0.33%higher than those obtained by ion chromatography,indicating that they are consistent with the actual values,and the relative standard deviation is less than 3%.