PROCESS AND SYSTEM FOR PRODUCING METALIZED AGGLOMERATES AND RECOVERY OF NON-FERROUS VALUES FROM WASTE MATERIALS

摘要

1422232 Metallized pellets HARSCO CORP 10 Jan 1973 1418/73 Heading C1A [Also in Division C7] A process for producing agglomerates from batches of waste material of the type containing ferrous and zinc values comprises: processing each batch of waste as necessary to provide dust; testing each batch for its zinc content; combining batches into fractions of like zinc content; separately storing the fractions; selectively discharging dust from the separately stored fractions and blending the dust together to provide a product having a predetermined zinc content; pelletizing the product; indurating the pellets and heating the pellets with a reductant in a reducing atmosphere to volatilize the zinc values and to form an agglomerate substantially free of zinc. The process is applicable to metallurgical dust from iron and steel-making especially from oxygen blown processes. The pellets can be indurated by heating pre-dried pellets at 300‹ to 1900‹ F. and reduction may be carried out by passing them together with a reductant through a furnace in countercurrent to combustion gases, at a temperature of 1400‹ to 2500‹ F. The zinc values are recovered and the metallized pellets are cooled by liquid in the presence of air without contamination from the combustion gases, giving a material with less than 0À2% zinc suitable for recharging into a metallurgical furnace. The magnetic portion of the product may be separated magnetically and divided into larger and smaller size fractions, and the smaller fraction is returned to the pelletizing step. Calcium carbonate may be added as a desulphurization agent during the reduction step.