ABSTRACT
Industrial processes often release by-products during the refining of
raw materials, combustion, filtering, cleaning of effluents, etc. Materi-
als such as smelting slag and combustion ash are also by-products.
Industrial processes often release by-products during the refining of
raw materials, combustion, filtering, cleaning of effluents, etc. Materi-
als such as smelting slag and combustion ash are also by-products.