Kev kho cov dej khib nyiab uas muaj chromium hauv electroplating

Kev sib piv ntawm cov teebmeem kho mob ntawm ferrous sulfate thiab sodium bisulfite

Cov txheej txheem ntawm electroplating ntau lawm yuav tsum tau galvanized, thiab nyob rau hauv cov txheej txheem ntawm galvanized purification, feem ntau lub Hoobkas electroplating yuav siv chromate, yog li cov dej khib nyiab electroplating yuav tsim ntau cov dej khib nyiab uas muaj chromium vim yog chromium plating. Cov chromium hauv cov dej khib nyiab uas muaj chromium muaj hexavalent chromium, uas yog lom thiab nyuaj rau tshem tawm. Hexavalent chromium feem ntau hloov mus rau trivalent chromium thiab tshem tawm. Rau kev tshem tawm cov dej khib nyiab electroplating uas muaj chrome, cov tshuaj coagulation thiab nag feem ntau siv los tshem tawm nws. Feem ntau siv yog ferrous sulfate thiab lime reduction precipitation method thiab sodium bisulfite thiab alkali reduction precipitation method.

1. txoj kev txo cov dej nag los ntawm ferrous sulfate thiab lime

Ferrous sulfate yog ib qho coagulant acid muaj zog nrog cov khoom oxidation-reducing muaj zog. Ferrous sulfate tuaj yeem raug txo ncaj qha nrog hexavalent chromium tom qab hydrolysis hauv cov dej khib nyiab, hloov nws mus rau hauv ib feem ntawm trivalent chromium coagulation thiab nag lossis daus, thiab tom qab ntawd ntxiv txiv qaub ntsuab los kho tus nqi pH txog li 8 ~ 9, yog li nws tuaj yeem pab cov tshuaj tiv thaiv coagulation los tsim cov chromium hydroxide nag lossis daus, qhov kev tshem tawm ntawm chromate tuaj yeem ncav cuag li 94%.

Ferrous sulfate ntxiv rau cov kua qaub ntsuab coagulant txo cov chromate precipitation muaj cov txiaj ntsig zoo rau kev tshem tawm chromium thiab tus nqi qis. Qhov thib ob, tsis tas yuav kho tus nqi pH ua ntej ntxiv ferrous sulfate, thiab tsuas yog xav tau ntxiv txiv qaub ntsuab los kho tus nqi pH. Txawm li cas los xij, vim muaj ntau ntawm ferrous sulfate dosing kuj ua rau muaj kev nce ntxiv ntawm cov av nkos hlau, ua rau tus nqi ntawm kev kho sludge nce ntxiv.

2, .sodium bisulfite thiab alkali txo cov dej nag txoj kev

Sodium bisulfite thiab alkali txo cov dej nag chromate, pH ntawm cov dej khib nyiab raug kho rau ≤2.0. Tom qab ntawd sodium bisulfite raug ntxiv los txo cov chromate rau trivalent chromium, thiab cov dej khib nyiab nkag mus rau hauv pas dej ua ke tom qab kev txo qis tiav, cov dej khib nyiab raug pumped mus rau lub pas dej tswj hwm kom kho, thiab tus nqi pH raug kho rau kwv yees li 10 los ntawm kev ntxiv cov alkali nodes, thiab tom qab ntawd cov dej khib nyiab raug tso tawm mus rau lub tank sedimentation kom precipitate chromate, thiab tus nqi tshem tawm tuaj yeem ncav cuag li 95%.

Txoj kev siv sodium bisulfite thiab alkali txo cov dej nag chromate zoo rau kev tshem tawm chromium, thiab nws tus nqi siab dua li ferrous sulfate, thiab lub sijhawm kho mob ntev dua, thiab tus nqi pH yuav tsum tau kho nrog kua qaub ua ntej kho. Txawm li cas los xij, piv nrog kev kho mob ferrous sulfate, nws yeej tsis tsim cov sludge ntau dhau, txo tus nqi ntawm kev kho sludge, thiab cov sludge kho feem ntau tuaj yeem rov siv dua.