Kalafo ea metsi a litšila a nang le chromium ho electroplating

Papiso ea liphello tsa kalafo ea ferrous sulfate le sodium bisulfite

Ts'ebetso ea tlhahiso ea electroplating e hloka ho galvanized, 'me ts'ebetsong ea ho hloekisa galvanized, ha e le hantle fektheri ea electroplating e tla sebelisa chromate, kahoo metsi a litšila a electroplating a tla hlahisa palo e kholo ea metsi a litšila a nang le chromium ka lebaka la chromium plating. Chromium e metsing a litšila a nang le chromium e na le hexavalent chromium, e chefo 'me e thata ho e tlosa. Hexavalent chromium hangata e fetoloa ho ba trivalent chromium ebe e tlosoa. Bakeng sa ho tlosa metsi a litšila a electroplating a nang le chrome, ho kopana ha lik'hemik'hale le pula hangata ho sebelisoa ho e tlosa. Hangata ho sebelisoa mokhoa oa ferrous sulfate le lime reduction precipitation le sodium bisulfite le alkali reduction precipitation.

1. mokhoa oa ho fokotsa pula ea ferrous sulfate le lime

Ferrous sulfate ke coagulant e matla ea asiti e nang le thepa e matla ea ho fokotsa oxidation. Ferrous sulfate e ka fokotsoa ka ho toba ka hexavalent chromium kamora hydrolysis metsing a litšila, e fetoloa karolo ea trivalent chromium coagulation le precipitation, ebe e eketsa lime ho fetola boleng ba pH ho hoo e ka bang 8 ~ 9, e le hore e ka thusa karabelo ea coagulation ho hlahisa precipitation ea chromium hydroxide, phello ea ho tlosoa ha chromate e ka fihla ho hoo e ka bang 94%.

Ho fokotsa chromate ea ferrous sulfate hammoho le lime coagulant ho na le phello e ntle ho tlosoeng ha chromium le litšenyehelo tse tlase. Ea bobeli, ha ho hlokahale ho fetola boleng ba pH pele ho eketsoa ferrous sulfate, 'me ho hlokahala feela ho eketsa lime ho fetola boleng ba pH. Leha ho le joalo, ka lebaka la bongata ba tekanyo ea ferrous sulfate le hona ho bakile keketseho e kholo ea seretse sa tšepe, e leng se ileng sa eketsa litšenyehelo tsa kalafo ea seretse.

2,. sodium bisulfite le mokhoa oa ho fokotsa pula ka alkali

Ka lebaka la sodium bisulfite le alkali reduction precipitation chromate, pH ea metsi a litšila e fetoloa ho ≤2.0. Ebe sodium bisulfite e eketsoa ho fokotsa chromate ho ba trivalent chromium, 'me metsi a litšila a kena letamong le felletseng kamora hore phokotso e phetheloe, metsi a litšila a pompeloa letamong le laolang bakeng sa tokiso, 'me boleng ba pH bo fetoloa ho ba hoo e ka bang 10 ka ho eketsa li-node tsa alkali, ebe metsi a litšila a tšolleloa tanka ea sedimentation ho thibela chromate, 'me sekhahla sa ho tlosoa se ka fihla ho hoo e ka bang 95%.

Mokhoa oa ho sebelisa sodium bisulfite le alkali reduction precipitation chromate o motle bakeng sa ho tlosa chromium, 'me litšenyehelo tsa oona li phahame ho feta ferrous sulfate,' me nako ea karabelo ea kalafo e telele haholo, 'me boleng ba pH bo hloka ho fetoloa ka asiti pele ho phekolo. Leha ho le joalo, ha e bapisoa le phekolo ea ferrous sulfate, ha e le hantle ha e hlahise seretse se ngata haholo, e leng se fokotsang haholo litšenyehelo tsa phekolo ea seretse, 'me seretse se phekoloang hangata se ka sebelisoa hape.