Daim ntawv thov: Lub nplhaib tiaj tus siab gradient sib nqus sib nqus yog dav siv hauv ntub dej hematite, limonite, siderite, chromite, ilmenite, wolframite, tantalum thiab niobium ore thiab lwm yam tsis muaj zog hlau nplaum, thiab cov minerals uas tsis yog xim hlau, xws li quartz, feldspar rau tshem tawm impurity hlau thiab purification. .