Sekundarne sirovine kalaja i postupci njihove prerade

Abstract

Najznačajnije sekundarne sirovine kalaja su: otpadni beli limovi i međuprodukti njihove proizvodnje (kalajne šljake, mulj i sunđer), metalna ambalaža, olovo-kalajne šljake i legure, amortizovani hladnjaci iz automobilske industrije i dr. Tehnološki postupci njihove regeneracije obuhvataju dve osnovne faze: pripremu otpada i njegovu metaluršku preradu. Priprema metalne ambalaže za metaluršku preradu je veoma važna faza i obuhvata veliki broj tehnoloških operacija, kao sto su: sakupljanje, sortiranje, pranje, usitnjavanje, odmašćivanje i dr. Priprema otpadnog belog lima je jednostavnija usled lakšeg sakupljanja i manje zaprljanosti. Prerada pripremljenog otpada vrši se primenom postupka hlorovanja, elektrolitičkog rastvaranja i taloženja ili alkalnog luženja i elektrolize.Prerada kalajne šljake, mulja i sunđera vrši se primenom postupka redukcionog topljenja, a dobijeni sirovi kalaj rafiniše u više stupnjeva.

Main resources of tin secondary raw materials are: residual tin-plates and by-products from their production (tin slags, sludges and sponges), metallic packings, lead-tin slags and alloys, amortised coolers from cars etc. The technological procedure for their processing includes two basic stages: pretreatment of the scrap and its metallurgical processing. The tin-plated cans pretreatment is a very important phase and it includes the following operations, cans collection, sorting, washing, crushing, warnish removal etc. Due to the easier collection and lower grade of impurities, the pretreatment of the waste tin plates is simpler in comparison with the tin-plated cans. The processing of the prepared scrap, can be carried out in two ways. In one way, the processing consists of chlorination treatment, electrolytical dissolution and precipitation, while in the other way alkaline leaching and electrolysis are employed. The processing of the tin slags, sludges and sponges can be carried out using reductional smelting process and refining of obtained secondary tin.