摘要
本文在绘制出Ag-SO_3^(2-)-H_2O系电势—pH图,且对各种还原剂还原Ag(SO_3)_2^(3-)进行热力学分析的基础上,采用静态法测试了甲醛、联氨、连二亚硫酸钠、抗坏血酸及硼氢化钾与Ag(SO_3)_2^(3-)溶液等当量混合以还原沉析银的得率,获得甲醛是最有效的还原剂。通过正交试验,得知甲醛和Ag(SO_3)_2^(3-)等当量反应沉析银的最佳条件是:pH=12.00,T=35℃±0.2,Ag^+∶SO_3^(2-)=1∶4(摩尔比)。经综合试验获得银的还原沉析率在98.5％以上。
While plotting the E-pH diagram of Ag-SO32-H2O system, we analyse thermodynamics which shows thas th Ag(SO3)32- is reduced by each reducing agent. A stationary experimental investigation is presented that Ag(SO3)32-is reduced by formaldehyde solution, hydrazine, sodium hydrosulfite, ascorbic acid and potassium borohydride. The best reducing agent is formol solution. By using orthogonal test, the optimun condition for the quantitative reduction of silver ( I ) by formaldehyde solution is established. The order of each factor to influence the reaction is found. In the mixture solution of original concentration of 0.0500mol/1 HCHO and 0.1000 mol/1 AgNO3, the molar ratio of SO32- to Ag+ is 4:1 and pH = 12.00 is selected.The reaction is carried at 35℃ and the persentage of precipitating silver power above 98.5%.
出处
《杭州大学学报（自然科学版）》
CSCD
1989年第1期59-65,共7页
Journal of Hangzhou University Natural Science Edition
基金
国家自然科学基金资助项目
关键词
甲醛
沉析
银
二亚硫酸合银
formaldehyde
bis (sulfite) argentate ( I )
