Phosphoric acid occupies ib tug tshwj xeeb txoj hauj lwm ntawm industrial acids. Tsis zoo li nitric acid, nws tsis muaj zog oxidizing, tab sis nws nthuav tawm qhov sib txawv thiab feem ntau underestimated corrosion kev sib tw. High viscosity, variable purity, thiab nquag kis nrog fluorides los yog cov khib nyiab hloov phosphoric acid ua rau hauv ib puag ncig nyuaj uas cov khoom siv tsis tuaj yeem txiav txim los ntawm acidity ib leeg. Nyob rau hauv cov ntsiab lus no, quartz immersion heaters feem ntau xaiv rau lawv cov tshuaj inertness -tab sis lawv tiag tiag - ntiaj teb no kev ua tau zoo nyob ntawm ib tug nuanced nkag siab txog yuav ua li cas phosphoric acid coj nyob rau hauv tshav kub.
Los ntawm kev pom tshuaj ntshiab, siab -purity fused quartz qhia tau zoo heev tiv thaiv phosphoric acid. Silicon dioxide tsis nkag siab nrog phosphate ions, thiab qhov tsis muaj cov hlau nplaum yuav tshem tawm cov txheej txheem electrochemical corrosion classical. Qhov no ua rau quartz hauv paus ruaj khov dua li cov hlau feem ntau nyob rau hauv kev sib cuag nrog phosphoric acid, tshwj xeeb tshaj yog nyob rau hauv siab concentrations qhov twg carbon steels thiab stainless steels pib raug kev txom nyem los ntawm generalized corrosion los yog pitting.
Txawm li cas los xij, phosphoric acid tsis tshua muaj nyob rau hauv cov tshuaj "huv" nruab nrab hauv kev ua lag luam. Hauv kev tsim cov chiv, kev kho saum npoo, thiab kev ua tshuaj lom neeg tshwj xeeb, phosphoric acid feem ntau muaj fluorides, sulfates, tshem tawm cov khib nyiab, lossis hlau ions nqa los ntawm cov dej ntws tawm. Cov impurities no tsis tas yuav tawm tsam quartz ncaj qha, tab sis lawv cuam tshuam rau kev hloov hluav taws xob, qhov ntub dej ntawm qhov chaw, thiab qhov ntsuas kub hauv zos -tag nrho cov uas cuam tshuam ncaj qha rau lub tshuab cua sov.
Ib qho ntawm qhov sib txawv tseem ceeb tshaj plaws ntawm phosphoric thiab nitric acid yog nyob rau hauv kev hloov pauv hauv tshav kub. Phosphoric acid ua viscous nce ntxiv thaum concentration nce, tshwj xeeb tshaj yog nyob rau hauv qis kub. Thaum pib cua sov, cov cheeb tsam kub hauv cheeb tsam tuaj yeem tsim nyob ze ntawm lub tshuab cua sov ua ntej cov khoom sib txuas ua kom ruaj khov. Rau cov cua sov quartz, qhov no txhais tau hais tias lub raj yuav muaj qhov kub thiab txias tshaj qhov xav tau, txawm tias tag nrho cov txheej txheem kub tseem nyob nruab nrab. Sij hawm dhau mus, rov raug rau cov thermal gradients tuaj yeem qhia txog kev ntxhov siab hauv lub quartz, tshwj xeeb tshaj yog tias lub zog ceev tsis tau ua tib zoo tswj.
Lwm tus yam ntxwv ntawm phosphoric acid processing yog scale tsim. Raws li qhov kub thiab txias, cov ntsev yaj thiab cov tshuaj tiv thaiv los ntawm cov khoom siv tuaj yeem ua rau cov cua sov. Quartz nws tus kheej tsis catalyze deposition, tab sis ib zaug ib txheej txheej txheej, nws ua raws li ib tug thermal insulator. Qhov kev rwb thaiv tsev no ua rau lub quartz nto kub ntxiv, ua kom lub zog thermal tsis muaj qhov pom kev zoo nkauj. Ntau lub quartz rhaub tsis ua hauj lwm hauv phosphoric acid systems yog li misdiagnosed li tshuaj tua kab mob, thaum qhov tseeb ua rau kub tsub kom nyob rau hauv ib tug adherent deposit txheej.
Lub luag haujlwm ntawm cov tshuaj fluoride yuav tsum tau saib xyuas tshwj xeeb. Txawm tias cov kab mob ntawm hydrofluoric acid los yog cov tshuaj fluorides soluble hloov pauv cov toj roob hauv pes zoo sib xws. Fluorides nquag tawm tsam silica, hloov cov silicon dioxide ruaj khov rau hauv cov dej tsis muaj zog lossis soluble silicon fluorides. Hauv cov phosphoric acid ntws los ntawm cov pob zeb phosphate, muaj fluoride muaj ntau tshwj tsis yog raug tshem tawm. Nyob rau hauv cov xwm txheej zoo li no, quartz heaters poob lawv qhov zoo dua, thiab kev pabcuam lub neej tuaj yeem poob qis. Vim li no, phosphoric acid daim ntawv thov yuav tsum tau soj ntsuam tsis yog los ntawm nominal acid muaj pes tsawg leeg, tab sis los ntawm impurity profiles thiab kev tswj cov txheej txheem ntws.
Kev sib xyaw tshuab kuj cuam tshuam rau kev ua haujlwm corrosion. Phosphoric acid systems feem ntau ua haujlwm tsis tu ncua rau lub voj voog ntev, nrog kev kaw tsis tu ncua. Thaum lub caij txias, cov kua qaub kua qaub yuav ua rau qee qhov ntws tawm, tawm hauv cov seem ntawm cov quartz raug rau huab cua thaum tseem coated nrog cov concentrated acid residues. Qhov no ua rau tsis sib xws thermal contraction thiab localized chemical concentration cuam tshuam thaum rov pib dua. Cov cua sov tsim los tsis suav rau cov kev ua haujlwm tiag tiag no tuaj yeem muaj kev tawg lossis degradation ntawm qhov chaw tsis cuam tshuam nrog kev ruaj khov- xeev chemistry.
Nyob rau hauv kev sib piv rau nitric acid kev pab, qhov twg oxidation dominates cov khoom xaiv, phosphoric acid xav tau kev saib xyuas rau thermal tswj, impurity tswj, thiab fouling cwj pwm. Quartz heaters ua tau zoo thaum cov xwm txheej no raug kho kom raug. Low to moderate power density, stable immersion depth, and effective cleaning protocols significantly extend operational life. Hloov pauv, kev kho phosphoric acid raws li qhov "mob" ib puag ncig tsuas yog vim nws tsis muaj zog oxidizing zog feem ntau ua rau ua tsis tiav ntxov.
Hauv kev xaus, quartz immersion heaters yeej muaj peev xwm tiv taus corrosion hauv phosphoric acid ua -tab sis tsuas yog nyob rau hauv cov ciam teb kom meej meej. Lawv cov tshuaj inertness muab lub hauv paus zoo, tab sis lawv lub sijhawm ntev - kev cia siab yog tswj hwm los ntawm kev hloov pauv hluav taws xob, kev pheej hmoo kis kab mob, thiab cov txheej txheem - theem tsim kev xaiv. Thaum xaiv nrog kev nkag siab tag nrho ntawm cov kev txwv no, quartz heaters muab kev ua tau zoo sib xws, kwv yees tau zoo. Thaum xaiv raws li kev sib raug zoo ntawm tshuaj lom neeg ib leeg, lawv cov txiaj ntsig tuaj yeem raug cuam tshuam sai sai los ntawm cov txheej txheem tsis ua haujlwm tshuaj lom neeg.
Phosphoric acid tsis aggressively rhuav tshem cov ntaub ntawv thaum hmo ntuj. Hloov chaw, nws nthuav tawm qhov tsis muaj zog maj mam, dhau los ntawm qhov tsis sib xws ntawm cov cua sov, kev tso tawm, thiab impurity -kev sib cuam tshuam. Quartz heaters, thaum teev kom raug, yog ib qho ntawm ob peb txoj kev daws teeb meem uas muaj peev xwm ua tau raws li qhov kev sib tw no nrog kev ruaj ntseg tsis yog luv luv - lub sij hawm tsis kam.
