论文部分内容阅读
(一)概述电解法提纯银,一般采用硝酸银溶液作电解液,其中含银为20～100克/升浓度,含硝酸为0.5～1%,铜的含量宜少,最多不宜超过150克/升浓度。一般工艺条件如下:极间距50～60毫米。槽电压1～2伏间。电流密度200～300安/米~2,阳极中杂质少时可升至500安/米~2。电解液的温度在25～30℃之间。阳极用丝绸或緻密隔膜包果以收集阳极泥。阴极一般采用铝板制作。电解一公斤银电力消耗约0.5瓩/小时。电流效率为90～95%,残阳极量为原阳极量的15～20%。精炼用的粗银阳极中若含有铜、锌、镉、镍、铝、锡、铋、锑、金、钯、铂、硒、碲等杂质,当电解时,则银、铜、锌、镉和镍溶解进入溶液;金、钯(当硝酸浓度小的情况下)铂、硒和碲均不溶解,成粉末落于阳极泥中;铝、锑、铋和锡也溶解于电解液
(A) Overview Electrolytic purification of silver, the general use of silver nitrate solution for the electrolyte, including silver 20 ~ 100 g / L concentration, containing nitric acid 0.5 ~ 1%, the content of copper should be less, the maximum should not exceed 150 g / Ascent concentration. General process conditions are as follows: pole spacing 50 ~ 60 mm. Slot voltage 1 ~ 2 volts. Current density 200 ~ 300A / m ~ 2, the anode can rise to less than 500A / m ~ 2 when there is little impurity. Electrolyte temperature between 25 ~ 30 ℃. Anode silk or dense diaphragm baguette to collect anode slime. Cathode commonly used aluminum production. Electrolysis one kilogram of silver electricity consumption of about 0.5 瓩 / hour. The current efficiency is 90-95%, the residual anode is 15-20% of the original anode. When the crude silver anode for refining contains impurities such as copper, zinc, cadmium, nickel, aluminum, tin, bismuth, antimony, gold, palladium, platinum, selenium and tellurium, Nickel dissolved into the solution; gold, palladium (in the case of nitric acid concentration is small) platinum, selenium and tellurium are not dissolved into powder fall in the anode mud; aluminum, antimony, bismuth and tin are also dissolved in the electrolyte