Oxide and Dross Inclusions

Oxide and dross inclusions Entrapment of foreign matter (i) Increase care and cleanliness during pouring ... 

Scrap that is unsuitable for recycling into products by the primary aluminum producers is used in the secondary aluminum industry for castings that have modest property requirements. Oxide formation and dross buildup are encountered in the secondary aluminum industry, and fluxes are employed to assist in the collection of dross and removal of inclusions and gas. Such fluxes are usually mixtures of sodium and potassium chlorides. Fumes and residues from these fluxes and treatment of dross are problems of environmental and economic importance, and efforts are made to reclaim both flux and metal values in the dross. 

Quality control problems with melting aluminum and its alloys include oxide (dross) formation and hydrogen absorption. These two phenomena can have a bad effect on product quality by making oxide inclusions or porosity. 

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