Residuals, such as slag particles, from iron- and/or steel-making, and/or water-leached eluates thereof, are added directly to a conventional or multi-staged anaerobic digester or other sewage sludge or biosolid handling process. The slag particles or other residuals sorb, sequester, immobilize, or otherwise promote the removal of phosphorus and/or sulfur from wastewater, sludge, or biosolids being treated, such that the associated aqueous phase concentrations of phosphorus and sulfur are significantly reduced.

Weak acid lixiviants are used to selectively extract calcium from various sources (e.g., steel slag, impure lime, dolomite). Preferably, non-amine weak acids (e.g., weak acids that do not include an amine) as lixiviants are used. Such lixiviants can be used in stoichiometric quantities relative to calcium content of the calcium source material.

Systems and methods are described in which spent pickle liquor from metal cleaning processes is utilized to regenerate a lixiviant used to recover valuable metals from industrial waste and other sources. The spent pickle liquor is neutralized and solvated metals in the spent pickle liquor are precipitated in this process. When the industrial waste is slag from a metal refining process a partially closed metal production process can be implemented, where spent pickle liquor from cleaning of the refined metal is used to regenerate a lixiviant used to recover a different, valuable metal from a waste slag of the process, with precipitated salts from the lixiviant regeneration being returned as a raw material in the metal refining process. As a result waste streams from these processes are dramatically reduced or eliminated.

Systems and methods are described in which spent pickle liquor from metal cleaning processes is utilized to regenerate a lixiviant used to recover valuable metals from industrial waste and other sources. The spent pickle liquor is neutralized and solvated metals in the spent pickle liquor are precipitated in this process. When the industrial waste is slag from a metal refining process a partially closed metal production process can be implemented, where spent pickle liquor from cleaning of the refined metal is used to regenerate a lixiviant used to recover a different, valuable metal from a waste slag of the process, with precipitated salts from the lixiviant regeneration being returned as a raw material in the metal refining process. As a result waste streams from these processes are dramatically reduced or eliminated.

A coupling system of copper slag recycling and CO.sub.2 mineralization process based on industrial solid waste includes the following steps: obtaining copper slags, performing a slag forming treatment, obtaining reforming slags, obtaining sponge iron, coupling the reforming slag with a CO.sub.2 mineralization process based on industrial solid waste, and coupling the CO.sub.2 generated in the process of obtaining sponge iron with the CO.sub.2 mineralization process based on industrial solid waste. The system includes a slag forming treatment device, a secondary treatment device, a first coupling device, and a second coupling device. The coupling system couples the recycling of copper slag with the existing CO.sub.2 mineralization process based on industrial solid waste. Various production lines can be organically integrated in a green and clean manner for both reforming slag and flue gas.

Systems and methods for processing slag produced by iron and steel making processes are disclosed. The slag is treated produce a series of valued industrial products, such as metal oxides, metal carbonates, rare-earth metals, and water glass. The systems and methods also integrate slag processing with CO.sub.2 sequestration and flue gas desulphurization. Processing slag minimizes the land use for stockpiling or landfilling wastes produced from iron and steel making processes and protects the ground water underneath. Overall, the solid and gaseous emissions of an energy-intensive and highly polluted industrial process have been largely reduced, recycled and valorized in order to achieve a near zero-emission goal.

Systems and methods for processing slag produced by iron and steel making processes are disclosed. The slag is treated produce a series of valued industrial products, such as metal oxides, metal carbonates, rare-earth metals, and water glass. The systems and methods also integrate slag processing with CO.sub.2 sequestration and flue gas desulphurization. Processing slag minimizes the land use for stockpiling or landfilling wastes produced from iron and steel making processes and protects the ground water underneath. Overall, the solid and gaseous emissions of an energy-intensive and highly polluted industrial process have been largely reduced, recycled and valorized in order to achieve a near zero-emission goal.

A process for the production of a crude solder composition includes the provision of a first solder refining slag that includes tin and/or lead. The process further includes the steps of partially reducing the first solder refining slag, thereby forming a crude solder metal composition and a second solder refining slag, followed by separating the second solder refining slag from the crude solder metal composition, and partially reducing the second solder refining slag, thereby forming a second lead-tin based metal composition and a second spent slag followed by separating the second spent slag from the second lead-tin based metal composition A copper containing fresh feed is added to step (ii), preferably before reducing the second solder refining slag.

A process for the production of a crude solder composition includes the provision of a first solder refining slag that includes tin and/or lead. The process further includes the steps of partially reducing the first solder refining slag, thereby forming a crude solder metal composition and a second solder refining slag, followed by separating the second solder refining slag from the crude solder metal composition, and partially reducing the second solder refining slag, thereby forming a second lead-tin based metal composition and a second spent slag followed by separating the second spent slag from the second lead-tin based metal composition A copper containing fresh feed is added to step (ii), preferably before reducing the second solder refining slag.

A plant for the treatment and recovery of white slag resulting from steelmaking processes. The plant including at least one basic frame; at least one work chamber, movable in rotation around a relevant axis and configured to receive and treat the white slag, the latter being moved forward along at least one direction of treatment. The work chamber including at least one loading portion through which said white slag is loaded; at least one cooling portion arranged downstream of said loading portion and comprising at least one treatment channel of said white slag; and cooling device/structure/component/or the like comprising at least one coolant to cool said white slag to obtain at least one recovery powder; and at least one sorting and separation portion of the recovery powder arranged.