聚氯化铝中氧化铝含量测试改进

Improvement on the Test Method of Aluminum Oxide Content in Polyaluminium Chloride

《水处理剂聚氯化铝》(GB/T 22627—2014)氯化锌标准溶液滴定法(仲裁法)中规定测试氧化铝含量时,液体试样称取量13~14 g,移取稀释后试液体积10.00 mL,样品处理完后加入指示剂,用氯化锌标准溶液滴定。试验发现:当氧化铝质量分数≥10%时,加指示剂后直接指示滴定终点,无法测试。为了能准确、有效地获得氧化铝含量的测试结果,文中通过改变液体聚氯化铝试样称取量或者稀释后试液取样体积后再进行含量测试。试验结果表明,当氧化铝质量分数<8%时,标准中测试参数有效,但当氧化铝质量分数≥8%,试样称取量应调整为6~7 g或溶解后试样的取样体积为5.00 mL,测试结果有效、准确。

According to the zinc chloride standard solution titrimetric method(arbitration method)in the National Standard《water treatment agent,polyaluminium chloride》(GB/T 22627—2014),when measuring the content of alumina oxide,the liquid sample weight was 13~14 g and the volume of the sample was 10.00 mL after being diluted,the indicator was added after the sample being treated,and finally titrated with the standard solution of zinc chloride.It was found that when the content of alumina oxide was more than 10%,the titration end point directly indicated after adding indicator,and it couldn’t be tested.In order to obtain the test results accurately and effectively,the content of alumina oxide was measured by changing the sample weight of the liquid polyaluminium chloride or the sample volume after dilution.It shows that the test parameters in the standard are valid when the content of alumina oxide is less than 8%,but when it is more than 8%,the liquid sample weight should be 6~7 g or the sample volume 5.00 mL,the test results can be effective and accurate.