Kuchiza madzi otayira okhala ndi chromium mu electroplating

Kuyerekeza zotsatira za mankhwala a ferrous sulfate ndi sodium bisulfite

Njira yopangira ma electroplating iyenera kupangidwa ndi galvanized, ndipo poyeretsa ma galvanized, chomera chopangira ma electroplating chimagwiritsa ntchito chromate, kotero madzi otayira a electroplating apanga madzi ambiri otayira okhala ndi chromium chifukwa cha chromium plating. Chromium yomwe ili m'madzi otayira okhala ndi chromium ili ndi hexavalent chromium, yomwe ndi poizoni komanso yovuta kuchotsa. Hexavalent chromium nthawi zambiri imasinthidwa kukhala trivalent chromium ndikuchotsedwa. Pochotsa madzi otayira okhala ndi chrome, mankhwala ophatikizika ndi mvula nthawi zambiri amagwiritsidwa ntchito pochotsa. Njira yodziwika kwambiri yogwiritsira ntchito ndi ferrous sulfate ndi lime reduction precipitation method ndi sodium bisulfite ndi alkali reduction precipitation method.

1. njira yochepetsera mvula ya ferrous sulfate ndi laimu

Ferrous sulfate ndi coagulant yamphamvu ya asidi yokhala ndi mphamvu zochepetsera okosijeni. Ferrous sulfate imatha kuchepetsedwa mwachindunji ndi hexavalent chromium pambuyo pa hydrolysis m'madzi otayidwa, ndikusandutsa gawo la trivalent chromium coagulation ndi precipitation, kenako ndikuwonjezera laimu kuti musinthe pH kukhala pafupifupi 8 ~ 9, kuti ithandize coagulation reaction kupanga chromium hydroxide precipitation, zotsatira zochotsa za chromate zitha kufika pafupifupi 94%.

Kuchepetsa chromate ya ferrous sulfate komanso laimu coagulant kumathandiza kwambiri kuchotsa chromium komanso mtengo wotsika. Kachiwiri, palibe chifukwa chosinthira pH musanawonjezere ferrous sulfate, ndipo muyenera kungowonjezera laimu kuti musinthe pH. Komabe, chifukwa cha kuchuluka kwa ferrous sulfate, kuchuluka kwa ferrous sulfate kunayambitsanso kuwonjezeka kwakukulu kwa matope achitsulo, zomwe zinawonjezera mtengo wochizira matope.

2,. sodium bisulfite ndi njira yochepetsera mvula ya alkali

Sodium bisulfite ndi alkali reduction precipitation chromate, pH ya madzi otayira imasinthidwa kufika pa ≤2.0. Kenako sodium bisulfite imawonjezedwa kuti ichepetse chromate kukhala trivalent chromium, ndipo madzi otayira amalowa mu dziwe lonse pambuyo poti kuchepetsako kwatha, madzi otayira amapopedwa kupita ku dziwe lowongolera kuti asinthe, ndipo pH imasinthidwa kufika pa 10 powonjezera ma alkali node, kenako madzi otayira amatulutsidwa ku thanki ya sedimentation kuti achepetse chromate, ndipo kuchuluka kwa kuchotsa kumatha kufika pafupifupi 95%.

Njira yogwiritsira ntchito sodium bisulfite ndi alkali reduction precipitation chromate ndi yabwino pochotsa chromium, ndipo mtengo wake ndi wokwera kuposa ferrous sulfate, ndipo nthawi yochitira chithandizo ndi yayitali, ndipo pH iyenera kusinthidwa ndi asidi musanagwiritse ntchito. Komabe, poyerekeza ndi chithandizo cha ferrous sulfate, kwenikweni siimapanga matope ambiri, zomwe zimachepetsa kwambiri mtengo wogwiritsira ntchito matope, ndipo matope omwe agwiritsidwa ntchito nthawi zambiri amatha kugwiritsidwanso ntchito.