Devices, systems, and methods for recovering metal constituents from a waste stream containing metals (e.g., incinerator ash) are described. The waste stream may include incinerator bottom ash, fly ash, or a combination thereof. A falling velocity separator is employed in combination with a centrifuge to separate and collect metals from the waste stream. The falling velocity separator uses a liquid to separate particles within incinerator ash according to the particles settling velocities. The centrifuge further separates particles from the incinerator ash according to density of the particles.

Devices, systems, and methods for recovering metal constituents from a waste stream containing metals (e.g., incinerator ash) are described. The waste stream may include incinerator bottom ash, fly ash, or a combination thereof. A falling velocity separator is employed in combination with a centrifuge to separate and collect metals from the waste stream. The falling velocity separator uses a liquid to separate particles within incinerator ash according to the particles settling velocities. The centrifuge further separates particles from the incinerator ash according to density of the particles.

The invention relates to a method of agglomerating iron oxide-containing residual substances, in particular scale and mill scale, wherein the residual materials and the paper sludge are dried and comminuted and agglomerates are produced by means of hot briquetting from the mixture comprising the residual substances and the paper sludge. In this way, mill scale briquettes of high strength and density can be produced which in steelmaking processes can then be charged into an electric arc furnace for the purpose of recycling the iron contained in the residual substances.

The invention relates to a method of agglomerating iron oxide-containing residual substances, in particular scale and mill scale, wherein the residual materials and the paper sludge are dried and comminuted and agglomerates are produced by means of hot briquetting from the mixture comprising the residual substances and the paper sludge. In this way, mill scale briquettes of high strength and density can be produced which in steelmaking processes can then be charged into an electric arc furnace for the purpose of recycling the iron contained in the residual substances.

A method for producing high-purity trimanganese tetraoxide from dust containing manganese includes adding sulfuric acid (H.sub.2SO.sub.4) and a reductant to manganese dust and leaching manganese therefrom; eliminating primary impurities by adding calcium hydroxide (Ca(OH).sub.2)) to the leached manganese solution acquired from the leaching step; eliminating secondary impurities by adding sulfides to the leached manganese solution from which primary impurities have been eliminated; precipitating manganese by using sodium hydroxide (NaOH) so as to control the pH in the leached manganese solution from which secondary impurities have been eliminated, and cleaning and drying the precipitated specimen; and acquiring high-purity trimanganese tetraoxide by injecting the dried specimen with air and heat-treating same under oxidizing conditions. Thus the present invention allows high-purity trimanganese tetraoxide to be produced from dust containing manganese, for use as material for a secondary battery.

A method for producing high-purity trimanganese tetraoxide from dust containing manganese includes adding sulfuric acid (H.sub.2SO.sub.4) and a reductant to manganese dust and leaching manganese therefrom; eliminating primary impurities by adding calcium hydroxide (Ca(OH).sub.2)) to the leached manganese solution acquired from the leaching step; eliminating secondary impurities by adding sulfides to the leached manganese solution from which primary impurities have been eliminated; precipitating manganese by using sodium hydroxide (NaOH) so as to control the pH in the leached manganese solution from which secondary impurities have been eliminated, and cleaning and drying the precipitated specimen; and acquiring high-purity trimanganese tetraoxide by injecting the dried specimen with air and heat-treating same under oxidizing conditions. Thus the present invention allows high-purity trimanganese tetraoxide to be produced from dust containing manganese, for use as material for a secondary battery.

The present application refers to zinc recovery process from steelworks powder, and to obtain a zinc sulfate solution with 12% Zn by weight with the expected degree for fertilizer. Such an approach can aim to add value to a steelmaking waste, by partially converting environmental liability in commercial product taking advantage of the steelworks' powder as a raw material for the production of a liquid fertilizer and ready for use, containing zinc and sulfur with low liquid effluent production. Such an approach can be advantageous as to simplicity, use of mild temperatures, use of a single reactant, overall conversion of the reactants into a product solution of commercial quality, ready for use as a foliar fertilizer with low generation of wastewater and without generation of additional waste.

The present application refers to zinc recovery process from steelworks powder, and to obtain a zinc sulfate solution with 12% Zn by weight with the expected degree for fertilizer. Such an approach can aim to add value to a steelmaking waste, by partially converting environmental liability in commercial product taking advantage of the steelworks' powder as a raw material for the production of a liquid fertilizer and ready for use, containing zinc and sulfur with low liquid effluent production. Such an approach can be advantageous as to simplicity, use of mild temperatures, use of a single reactant, overall conversion of the reactants into a product solution of commercial quality, ready for use as a foliar fertilizer with low generation of wastewater and without generation of additional waste.

A method for recovering heavy metals and rare earth elements from fly ash, coal ash, and unrefined mineral ores containing rare earth metals using an ionic liquid and an organic acid to solubilize the metals. The solubilized components are removed from the ionic liquid by electrochemical deposition. The heavy metals and rare earth elements are deposited onto an electrode, and then purified via electrochemical processing.

A method for recovering heavy metals and rare earth elements from fly ash, coal ash, and unrefined mineral ores containing rare earth metals using an ionic liquid and an organic acid to solubilize the metals. The solubilized components are removed from the ionic liquid by electrochemical deposition. The heavy metals and rare earth elements are deposited onto an electrode, and then purified via electrochemical processing.