佛尔哈德法测定氯化除汞上清液中的氯量

Determination of Chlorine in Mercury-eliminating Chloride Solution

控制pH4-6，用锌粉还原氯化除汞上清液中的汞（Ⅱ）离子，取置换后液加入过量的硝酸银标准溶液，以硫酸铁铵溶液作指示剂，用硫氰酸钾标准滴定溶液滴定来测定氯量。该方法的检出限：0．25mg／100mL，回收率：98％-101％。

Take the Zinc powder to reduce Mercury（Ⅱ）cation in upper clean solution of Mercury-eliminating chloride at the condition that pH is 4 to 6. Then get the diaplaced solution and add excessive standard Silver Nitrate solution. Use Ammonium Iron（Ⅲ）Sulphate dodecahydrate as colour indication agent and determine the Chlorine anion＇s content through Potassium Thiocyanate titration. The checking-out limit is 0.25 mg/100 mL,and recovery ratio is 98% to 100%.