電解法：由硫酸銨和硫酸配制成電解液，經(jīng)除雜質(zhì)后進(jìn)行電解，HSO4-在陽極放電而生成過二硫酸，再與硫酸銨反應(yīng)生成過硫酸銨，當(dāng)陽極液中過硫酸銨含量達(dá)到一定濃度，經(jīng)過濾、結(jié)晶、離心分離、干燥制得過硫酸銨成品。
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.
經(jīng)過除鐵和除雜質(zhì)后的精制電解液，由高位槽連續(xù)進(jìn)入隔膜電解槽，電解液的組成為：陰極液為硫酸280～340kg/m3；硫酸銨180～210kg/m3。陽極液為硫酸110～140kg/m3；硫酸銨300～340kg/m3。通常陽極的電流密度為20～25A/L，槽電壓為5.5～5.8V，電解溫度控制在25～30℃。槽電壓過高，易使已生成的過二硫酸水解成過硫酸而降低電流效率；槽溫過低，易析出過硫酸銨結(jié)晶，堵塞管路。為了提高電流效率，通常添加硫氰酸銨，其量約為電解液的0.015%～0.03%。電解后，陽極液中的過硫酸銨含量應(yīng)達(dá)到220～260kg/m3，收集于陽極液儲(chǔ)槽后，經(jīng)過濾加入結(jié)晶器內(nèi)，在攪拌下，通入冷凍劑進(jìn)行間接冷凍，使過硫酸銨結(jié)晶。待溫度降-8～-12℃時(shí)，停止冷凍。然后離心分離，再經(jīng)干燥，即得成品。母液循環(huán)使用。電解法的電流效率約為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%.
電解硫酸銨的硫酸溶液可制得過二硫酸銨。電解裝置為一放在燒杯中的帶底的容積為80～100mL的素?zé)赏玻卮赏矁?nèi)裝入陽極液，燒杯與素瓷筒之間裝陰極液。鉑絲制成的螺旋狀陽極插入陽極液中，以鉛板制成的圓筒狀的陰極置于素瓷筒外的陰極液中。將硫酸銨溶解在濃度為2mol/L的稀硫酸中制成飽和溶液，并以此溶液為陽極液，陰極液為等體積濃硫酸與水混合形成的稀硫酸溶液。燒杯放在冷水中冷卻，在電解過程中保持陽極液的溫度在10～20℃的范圍內(nèi)。在電流為2～3A下電解一段時(shí)間后，在素瓷筒中即會(huì)有過二硫酸銨的結(jié)晶析出。經(jīng)3～4h后，將陽極液中的全部結(jié)晶取出并用玻璃砂芯漏斗過濾，在40℃以下的溫度下進(jìn)行真空干燥，即可得到過二硫酸銨產(chǎn)品。濾液經(jīng)用硫酸銨飽和后，可再裝入素瓷筒中繼續(xù)電解。經(jīng)2～3次反復(fù)后，陽極液中硫酸過剩較多，可在冷卻的條件下用以硫酸銨飽和的氨水中和部分硫酸。經(jīng)幾次反復(fù)后，陰極液中的硫酸濃度會(huì)大大降低，甚變?yōu)閴A性，此時(shí)必須更換陰極液，否則電流會(huì)迅速減弱。
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 將硫酸銨飽和溶液和硫酸混合，濾去不溶物，作為電解液，以鉑作為電極，電解溫度維持在35～45℃為宜，電壓12A 左右，HSO4-子在陽極失電子生成過二硫酸，再與硫酸銨反應(yīng)生成過硫酸銨，總反應(yīng)式為：
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:
當(dāng)電解液中過硫酸銨達(dá)到一定濃度，調(diào)節(jié)PH＝7～8，然后將電解液過濾，濾液冷卻結(jié)晶，結(jié)晶用少量冷水洗滌合格后甩干，在40℃以下干燥，得試劑過硫酸銨。
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.
