渣 ⇒
渣 zhā, slag (in mining or smelting)/dregs
渣滓 zhāzǐ, residue/dregs/disreputable people
残渣 cánzhā, [殘渣], remainder/filtered out residue/sediment/waste product/debris/detritus/rubbish
渣子 煤渣 méizhā, slack
矿渣 kuàngzhā, [礦渣], slag (mining)
废渣 fèizhā, [廢渣], industrial waste product/slag
油渣 渣土 沉渣 豆腐渣 dòufuzhā, okara (i.e. soy pulp, a by-product of making soymilk or tofu)