Electrolysis method: the electrolyte is prepared from ammonium sulfate and sulfuric acid. After removing impurities, it is electrolyzed. HSO4 - discharges at the anode to generate persulfate, and then reacts with ammonium sulfate to generate ammonium persulfate. When the content of ammonium persulfate in the anode solution reaches a certain concentration, the finished product of ammonium persulfate is prepared by filtration, crystallization, centrifugal separation and drying.

经过除铁和除杂质后的精制电解液，由高位槽连续进入隔膜电解槽，电解液的组成为：阴极液为硫酸280～340kg/m3；硫酸铵180～210kg/m3。阳极液为硫酸110～140kg/m3；硫酸铵300～340kg/m3。通常阳极的电流密度为20～25A/L，槽电压为5.5～5.8V，电解温度控制在25～30℃。槽电压过高，易使已生成的过二硫酸水解成过硫酸而降低电流效率；槽温过低，易析出过硫酸铵结晶，堵塞管路。为了提高电流效率，通常添加硫氰酸铵，其量约为电解液的0.015%～0.03%。电解后，阳极液中的过硫酸铵含量应达到220～260kg/m3，收集于阳极液储槽后，经过滤加入结晶器内，在搅拌下，通入冷冻剂进行间接冷冻，使过硫酸铵结晶。待温度降-8～-12℃时，停止冷冻。然后离心分离，再经干燥，即得成品。母液循环使用。电解法的电流效率约为84%～85%。

The refined electrolyte after removing iron and impurities continuously enters the diaphragm electrolytic cell from the high-level cell. The composition of the electrolyte is as follows: the cathode liquid is sulfuric acid 280 ~ 340kg / m3; Ammonium sulfate 180 ~ 210kg / m3. The anode solution is sulfuric acid 110 ~ 140kg / m3; Ammonium sulfate 300 ~ 340kg / m3. Generally, the current density of anode is 20 ~ 25A / L, the cell voltage is 5.5 ~ 5.8v, and the electrolysis temperature is controlled at 25 ~ 30 ℃. If the tank voltage is too high, it is easy to hydrolyze the generated persulfate into persulfate and reduce the current efficiency; If the tank temperature is too low, it is easy to precipitate ammonium persulfate crystals and block the pipeline. In order to improve the current efficiency, ammonium thiocyanate is usually added, and its amount is about 0.015% ~ 0.03% of the electrolyte. After electrolysis, the content of ammonium persulfate in the anode solution shall reach 220 ~ 260kg / m3. After being collected in the anode solution storage tank, it is filtered and added into the crystallizer. Under stirring, refrigerant is introduced for indirect freezing to crystallize ammonium persulfate. When the temperature drops to - 8 ~ - 12 ℃, stop freezing. After centrifugation and drying, the finished product is obtained. Mother liquor is recycled. The current efficiency of electrolysis is about 84% ~ 85%.

电解硫酸铵的硫酸溶液可制得过二硫酸铵。电解装置为一放在烧杯中的带底的容积为80～100mL的素烧瓷筒，素瓷筒内装入阳极液，烧杯与素瓷筒之间装阴极液。铂丝制成的螺旋状阳极插入阳极液中，以铅板制成的圆筒状的阴极置于素瓷筒外的阴极液中。将硫酸铵溶解在浓度为2mol/L的稀硫酸中制成饱和溶液，并以此溶液为阳极液，阴极液为等体积浓硫酸与水混合形成的稀硫酸溶液。烧杯放在冷水中冷却，在电解过程中保持阳极液的温度在10～20℃的范围内。在电流为2～3A下电解一段时间后，在素瓷筒中即会有过二硫酸铵的结晶析出。经3～4h后，将阳极液中的全部结晶取出并用玻璃砂芯漏斗过滤，在40℃以下的温度下进行真空干燥，即可得到过二硫酸铵产品。滤液经用硫酸铵饱和后，可再装入素瓷筒中继续电解。经2～3次反复后，阳极液中硫酸过剩较多，可在冷却的条件下用以硫酸铵饱和的氨水中和部分硫酸。经几次反复后，阴极液中的硫酸浓度会大大降低，甚变为碱性，此时必须更换阴极液，否则电流会迅速减弱。

Ammonium persulfate can be prepared by electrolysis of sulfuric acid solution of ammonium sulfate. The electrolysis device is a plain porcelain cylinder with a bottom and a volume of 80 ~ 100ml placed in the beaker. The plain porcelain cylinder is filled with anode liquid, and the cathode liquid is filled between the beaker and the plain porcelain cylinder. The spiral anode made of platinum wire is inserted into the anode liquid, and the cylindrical cathode made of lead plate is placed in the cathode liquid outside the plain porcelain cylinder. Ammonium sulfate is dissolved in dilute sulfuric acid with a concentration of 2mol / L to make a saturated solution, which is used as the anode solution, and the cathode solution is a dilute sulfuric acid solution formed by mixing equal volume of concentrated sulfuric acid with water. The beaker is cooled in cold water, and the temperature of anode liquid is kept in the range of 10 ~ 20 ℃ during electrolysis. After electrolysis at a current of 2 ~ 3A for a period of time, there will be crystallization and precipitation of ammonium persulfate in the plain porcelain cylinder. After 3 ~ 4h, all the crystals in the anode solution are taken out, filtered with a glass sand core funnel, and vacuum dried at a temperature below 40 ℃ to obtain ammonium persulfate product. After the filtrate is saturated with ammonium sulfate, it can be put into a plain porcelain cylinder to continue electrolysis. After 2 ~ 3 repetitions, there is a lot of excess sulfuric acid in the anode solution. Under the condition of cooling, some sulfuric acid can be neutralized with ammonia saturated with ammonium sulfate. After several repetitions, the sulfuric acid concentration in the cathode liquid will be greatly reduced or even become alkaline. At this time, the cathode liquid must be replaced, otherwise the current will weaken rapidly.

制法 将硫酸铵饱和溶液和硫酸混合，滤去不溶物，作为电解液，以铂作为电极，电解温度维持在35～45℃为宜，电压12A 左右，HSO4-子在阳极失电子生成过二硫酸，再与硫酸铵反应生成过硫酸铵，总反应式为：

In the preparation method, the saturated solution of ammonium sulfate and sulfuric acid are mixed, the insoluble matter is filtered out as the electrolyte, platinum is used as the electrode, the electrolysis temperature is appropriate to be maintained at 35 ~ 45 ℃, the voltage is about 12a, HSO4 - loses electrons at the anode to form persulfate, and then reacts with ammonium sulfate to form ammonium persulfate. The general reaction formula is:

当电解液中过硫酸铵达到一定浓度，调节PH＝7～8，然后将电解液过滤，滤液冷却结晶，结晶用少量冷水洗涤合格后甩干，在40℃以下干燥，得试剂过硫酸铵。

When ammonium persulfate in the electrolyte reaches a certain concentration, adjust pH = 7 ~ 8, then filter the electrolyte, cool and crystallize the filtrate, wash the crystallization with a small amount of cold water until it is qualified, shake it dry, and dry it below 40 ℃ to obtain reagent Ammonium persulfate.