5公斤氟钠钠。 In the leaching step, each cubic meter of ammonia - ammonium sulfate solution was added 0. 3~0. 5kg sodium fluorosilicate. The purpose is to make the ammonia leaching reaction easier and more thorough. Adding an appropriate amount of sodium fluorosilicate can break the package of zinc-containing particles by a kind of ultrafine particles such as calcium hydroxide formed during the dissolution and conversion process of calcium sulfate in the ammonia solution. , the ultra-fine particles are layered and peeled off to achieve leaching.