Abstract: A method of pyroprocessing mineral ores. The method includes forming the mineral ore fines into small balls or pellets, drying and preheating the pellets and then subjecting the pellets to further heat with an oxidizing gas to substantially oxidize and indurate the pellets prior to discharging the pellets into a cooler. The essential equipment used in the process are machines such as a balling pan or drum for agglomerating the ore, a grate traveling through a furnace and a rotary kiln for transporting the pellets from the grate to a cooler. Also, means are provided to supply hot oxidizing gas to both the furnace and the kiln to heat the pellets. In addition, means are provided to supply an oxidizing gas beneath the tumbling bed of pellets in the kiln.

Abstract: There is disclosed a process for recovering valuable metals from a dust containing zinc comprising mixing the dust containing zinc with a reductant and a flux for regulating the basicity of slag, forming the mixture into pellets with a pelletizer, charging the pellets into a shaft type preheating-prereducing furnace provided with a preheating zone at the upper part and with a reducing zone at the lower part and removing, in the preheating zone, moisture and ignition loss components in the pellets, while prereducing in the reducing zone, the pellets under such conditions that a reduction of iron oxide is made to proceed selectively while the reduction of zinc oxide is suppressed to the possible minimum, charging the prereduced pellets into a melting furnace to melt and reduce them in the furnace, separating zinc, or zinc and lead, by evaporation followed by condensation to recover them, and separating iron and lead, or iron, according to the difference in their specific gravities to recover the iron as a molte

Abstract: A method of treating solid hazardous wastes containing unacceptable levels of leachable metals such as lead, cadmium and zinc includes mixing the solid waste with a buffering agent selected from the group consisting of magnesium oxide, magnesium hydroxide, reactive calcium carbonates and reactive magnesium carbonates, and with an additional agent which is an acid or salt containing an anion that forms substantially nonleachable forms of the metals, which additional agent is selected from the group consisting of triple superphosphate, ammonium phosphate, diammonium phosphate, phosphoric acid, boric acid and metallic iron so that under both acidic and nonacidic leaching conditions the metals in the mixture will be converted to substantially nonleachable forms.