Muaj ob peb yam uas ua rau muaj qhov nce ntawm cov nqi iav.
Cov nqi raw khoom: Tus nqi ntawm cov khoom siv raw siv hauv iav, xws li xuab zeb, dej qab zib tshauv, thiab limestone, tuaj yeem hloov pauv. Yog tias tus nqi ntawm cov ntaub ntawv no nce, nws ncaj qha cuam tshuam rau tag nrho cov nqi ntawm kev tsim iav, ua rau cov nqi siab dua.
Cov nqi zog: Cov iav ntau lawm yuav tsum muaj lub zog loj, tshwj xeeb tshaj yog nyob rau hauv cov txheej txheem melting thiab shaping. Yog tias cov nqi hluav taws xob nce, nws tuaj yeem cuam tshuam rau cov nqi tsim khoom ntawm iav thiab ua rau cov nqi siab dua.
Cov nqi thauj mus los: Cov khoom iav feem ntau loj thiab tsis yooj yim, yuav tsum tau tuav tshwj xeeb thiab ntim khoom thaum thauj. Yog tias cov nqi tsheb thauj mus los, suav nrog cov nqi roj thiab cov nqi thauj khoom, nce, nws tuaj yeem ntxiv rau tag nrho cov nqi ntawm iav, ua rau cov nqi siab dua.
Cov nqi ua haujlwm: Kev tsim iav yuav tsum muaj kev txawj ua haujlwm, tshwj xeeb tshaj yog nyob rau hauv kev tsim thiab ua tiav. Yog tias tus nqi ua haujlwm nce vim yog yam xws li kev nce nyiaj ua haujlwm lossis kev ua haujlwm tsis txaus, nws tuaj yeem ua rau nce nqi iav.
Kev lag luam xav tau thiab cov khoom siv: Kev hloov pauv hauv kev lag luam xav tau thiab cov khoom siv kuj tuaj yeem cuam tshuam cov nqi iav. Yog tias muaj kev xav tau ntau ntxiv rau cov khoom iav, nws tuaj yeem ua rau tus nqi siab dua li cov tuam txhab lag luam yuav tsum tau nqis peev hauv kev nthuav dav ntau lawm lossis nce nqi kom tau raws li qhov xav tau. Ib yam li ntawd, yog tias muaj kev txo qis hauv cov khoom lag luam vim muaj qhov cuam tshuam xws li kev cuam tshuam kev tsim khoom lossis kev cog qoob loo, nws tuaj yeem ua rau tus nqi siab dua.
Tsoom fwv cov cai thiab cov se: Tsoom fwv cov cai thiab cov se kuj tuaj yeem cuam tshuam tus nqi ntawm cov iav ntau lawm. Piv txwv li, yog tias muaj cov kev cai ib puag ncig nruj dua uas yuav tsum muaj cov tuam txhab iav los nqis peev hauv kev tswj cov pa phem, nws tuaj yeem ua rau lawv cov nqi ntau lawm thiab tom qab ntawd ua rau cov nqi siab dua. Ib yam li ntawd, yog tias muaj cov se ntau dua rau cov khoom siv iav, nws kuj tuaj yeem ua rau tus nqi nce ntxiv.
