Cov txheej txheem tsim khoom siv feem ntau yog cov txheej txheem neutralization, uas yog, tom qab phosphoric acid reacted nrog potassium hydroxide lossis potassium bicarbonate, thiab potassium carbonate, qhov kawg ntawm cov tshuaj tiv thaiv yog tswj, thiab cov tshuaj neutralization yog concentrated kom tshem tawm cov insolubles, thiab tom qab txias, nws yog crystallized, centrifuged thiab qhuav kom tau ib yam khoom. Txawm li cas los xij, vim tias phosphoric acid tau muab faib ua cov txheej txheem thermal phosphoric acid thiab cov txheej txheem ntub dej phosphoric acid, cov txheej txheem ntub dej phosphoric acid feem ntau yog ua los ntawm kev siv phosphate pob zeb thiab inorganic acid los tsim cov kua qaub tsis muaj zog raws li lub hauv paus ntsiab lus ntawm cov kua qaub muaj zog. Cov hauv paus hniav thiab lwm yam, xws li calcium, tsim calcium sulfate insoluble teeb meem, uas tau los ntawm kev pom.
Txawm li cas los xij, vim tias qhov zoo ntawm phosphate pob zeb yuav cuam tshuam rau qhov zoo ntawm ntub - txheej txheem phosphoric acid, qhov zoo ntawm phosphoric acid cov khoom npaj los ntawm ntub - txheej txheem phosphoric acid tsis ruaj khov. Nyob rau tib lub sijhawm, nws kuj ua rau cov phosphoric acid uas tau txais muaj cov ntsiab lus impurity siab dua thiab qis purity, yog li ntawd thaum siv phosphoric acid npaj los ntawm ntub dej - txheej txheem phosphoric acid los tsim cov khoom poov tshuaj phosphate, nws yuav tsis tsuas ua rau cov poov tshuaj phosphate tsawg hauv purity thiab tsis ruaj tsis khov, tab sis kuj yuav ua rau cov poov tshuaj sib xyaw nrog lwm cov poov tshuaj carbonate los yog poov tshuaj carbonate. impurity ntsiab los tsim insolubles, uas nyob rau hauv lem ua rau ib tug pov tseg ntawm poov tshuaj ions, uas ua rau ib tug nce nyob rau hauv cov nyiaj ntawm cov poov tshuaj hydroxide, poov tshuaj carbonate los yog poov tshuaj bicarbonate ntxiv, uas ua rau ntau dua kev npaj nqi thiab ntau dua kev siv.
Raws li kev npaj technology uas twb muaj lawm ntawm tripotassium phosphate, peb muab ib txoj hauv kev los npaj tripotassium phosphate los ntawm ntub - txheej txheem phosphoric acid, uas suav nrog cov kauj ruam hauv qab no:
(1) Siv ntub dej - txheej txheem phosphoric acid nrog phosphorus pentoxide concentration ntawm 15%, txheeb xyuas cov ntsiab lus ntawm sulfate radicals hauv nws, thiab ntxiv phosphate pob zeb hmoov rau nws. Tus nqi ntawm phosphate pob zeb hmoov ntxiv yog qhov loj piv ntawm sulfate radical cov ntsiab lus . 1: 1, tom qab 30 feeb ntawm cov tshuaj tiv thaiv, ntxiv ammonia dej los yog dhau hauv ammonia roj, kho cov pH mus rau 3, thiab lim kom tau slurry thiab lim residue;
(2) Siv cov poov tshuaj hydroxide, ntxiv poov tshuaj hydroxide rau slurry, thiab tswj cov molar piv ntawm cov poov tshuaj hydroxide rau cov nyiaj ntawm phosphorus pentoxide nyob rau hauv ntub dej - txheej txheem phosphoric acid yog 6: 1. Tom qab kev pub mis tiav lawm, Lub siab tsis zoo yog tswj tau rau 0MPa, thiab qhov kub yog 85℃rau evaporation thiab crystallization. Thaum muaj coob tus crystals tshwm nyob rau hauv cov kev daws teeb meem, nres evaporation, txias rau chav tsev kub, thiab lim kom tau cov niam cawv thiab cov khoom tseem ceeb; Cov khoom tseem ceeb yog ntxuav kom tau txais tripotassium phosphate.
Lub purity ntawm cov hais tias tripotassium phosphate yog 98.1%. Hauv kev ntxuav, cov kua ntxhua khaub ncaws uas ua los ntawm kev ntxuav yog rov qab mus rau qib 1 thiab tov nrog ntub dej - txheej txheem phosphoric acid. Nyob rau hauv lub evaporative crystallization, cov roj generated nyob rau hauv lub crystallization txheej txheem yog absorbed los ntawm dilute phosphoric acid, thiab ces rov qab mus rau tov nrog cov ntub dej - txheej txheem phosphoric acid nyob rau hauv kauj ruam 1. Qhov concentration ntawm dilute phosphoric acid yog 15%. Niam cawv raug xa mus rau cov kab sib xyaw ua chiv; cov lim residue raug xa mus rau lub compound fertilizer ntau lawm kab. Cov poov tshuaj hydroxide yog ib qho khoom ntxiv rau hauv slurry. Cov ntsiab lus ntawm phosphorus pentoxide ntawm phosphate pob zeb hmoov tsis tsawg dua 7%. Cov phosphate pob zeb hmoov hais tias muaj qhov me me ntawm 40 mesh.
