71. Yog vim li cas tsis nco qab txheej txheej thiab zinc hais feem ntau tshwm sim thaum lub sij hawm txhuas-zinc alloy potting ntawm steel kav, tshwj xeeb tshaj yog thaum pib? Cov kev daws teeb meem yog dab tsi?

Daim ntawv no tsis tham txog qhov chaw leaching tshwm sim los ntawm pickling, hnyav thiab ziab, tab sis tsuas yog tham txog qhov ua rau leaching me ntsis hauv kub -dip galvanizing.
(1) Cov txhuas hauv zinc-aluminium alloy reacts nrog huab cua los ua aluminium oxide. Cov kev sim kuaj pom tau tias zinc tshauv ntawm cov yeeb nkab steel qhov chaw nkag muaj kwv yees li 15.2% txhuas oxide. Aluminium oxide muaj qhov melting point ntawm 2050℃thiab qhov ceev ntawm 3.9-4.0 kg / L, thaum zinc oxide melts ntawm 1975℃nrog ib tug ceev ntawm 5.606 kg / L. Thaum ua haujlwm kub ntawm 480-510 degree, zinc kua qhov ntom ntom ntawm 6.54 txog 6.79 kg / L. Qhov ceev gradient no ua rau txhuas oxide nyob rau saum. Thaum cov yeeb nkab steel tsis zoo qhuav los yog nyob twj ywm hauv huab cua ntev ntev tom qab ziab, noo noo los ntawm cov kuab tshuaj reabsorbs. Raws li cov yeeb nkab nkag mus rau zinc da dej, nws thawj zaug hu rau txhuas oxide ua ntej zinc oxide (zinc tshauv). Cov tshuaj no ua raws li cov yeeb nkab nto, hlawv tawm cov kuab tshuaj thiab ua rau mottled txheej tsis xws luag.
(2) Thaum lub sij hawm pib thiab tom ntej no ntau lawm, txhuas nrog tsawg ntom thiab ntev lub sij hawm zoo li qub ntab mus rau saum npoo ntawm molten zinc. Thaum cov yeeb nkab steel coated nrog hnyav los rau hauv kev sib cuag nrog nws, cov tshuaj tiv thaiv nram qab no tshwm sim tam sim: 2Al + 3ZnCl₂ → 2AlCl₃ + 3Zn. Raws li pom nyob rau hauv kab zauv, ntau reactive txhuas instantly displaces zinc los ntawm cov kuab tshuaj compound, tsim txhuas trichloride (AlCl₃). Txawm li cas los xij, AlCl₃ sublimates ntawm 178℃. Ib yam li ntawd, txhuas reacts nrog ammonium chloride nyob rau hauv cov kuab tshuaj los ua AlCl₈NH₃, uas boils thiab evaporates ntawm ib ncig ntawm 400 degree. Yog li ntawd, cov tshuaj tiv thaiv no ua rau tag nrho cov chlorine cov ntsiab lus tseem ceeb rau kev pab plating, ua rau cov plating tsis tau.
(3) Qhov kub ntawm cov kua zinc feem ntau yog siab thaum pib ua haujlwm. Thaum cov kuab tshuaj los rau hauv kev sib cuag nrog zinc kua, lub cev adsorption thiab kev sib xyaw ntawm cov kuab tshuaj tsis tuaj yeem ua tiav raws sijhawm, thiab cov kuab tshuaj residue yog tsim. Cov kuab tshuaj poob nws txoj haujlwm, thiab cov dej ntws ntawm cov plating mottling yog tsim.
(4) Thaum cov yeeb nkab steel coated nrog hnyav yog muab tso rau hauv zinc da dej rau plating, nws yog ib qho tsim nyog yuav tsum tau yuam nws mus rau hauv zinc da dej nrog pliers thiab turntable. Kev sib cuag ntawm cov cuab yeej no thiab cov yeeb nkab steel yuav rhuav tshem cov zaj duab xis hnyav rau qhov sib txawv, yog li plating muaj peev xwm ntawm qhov chaw sib cuag yuav ploj thiab qhov chaw plating yuav raug tsim.
(5) Thaum cov khoom pib, cov txheej txheem kub tsis tau mus txog, thiab zinc da dej kub yog qis, lub sij hawm zinc immersion tsis txuas ntxiv, thiab txhuas da dej yog concentrated nyob rau saum npoo, cov tshuaj tiv thaiv ntawm hlau thiab zinc yog qeeb, thiab cov hlau - zinc alloy txheej tsis tuaj yeem tsim nyob rau hauv ib lub sij hawm luv luv, yog li thaum pawg tawm los, yuav muaj qee qhov tsis zoo ntawm cov yeeb nkab steel.
(6) Cov ntsiab lus txhuas ntau dhau hauv chav da dej galvanizing ua ke nrog cov zinc tsis ruaj khov tuaj yeem ua rau Fe-Al-Zn compound particles ncua hauv zinc da dej. Thaum cov kav hlau hla dhau, cov khoom no ua raws li cov yeeb nkab nto, uas ua rau muaj qhov tsis xws luag. Cov kev daws teeb meem: (1) Thaum pib tsim khoom, cov ntsiab lus txhuas hauv zinc da dej yuav tsum qis dua li ib txwm tsim, maj mam nce mus rau cov txheej txheem teev tseg raws li kev ua haujlwm normalize; (2) Tsis tu ncua txhuam cov zinc tshauv los ntawm zinc da dej nto ntawm cov yeeb nkab inlet; (3) Xyuas kom cov kuab tshuaj siv rau cov kav hlau yog qhuav, tsis txhob ya raws lossis tsis tiav; (4) Khaws cov zinc da dej kub hauv qhov kev pom zoo; (5) Tiv thaiv kev puas tsuaj rau cov yeeb nkab steel thaum thauj; (6) Muab cov kav hlau tso rau ntawm lub kaum sab xis mus rau hauv cov zinc da dej, txo qis rau ntawm qhov chaw.