A method of preparing metal hydroxides from industrial wastes or alkaline rocks is provided. The method comprise subjecting a mixture comprising a solvent and a solid substrate to a stimulus in order to leach a metal cation from the solid substrate into the solvent, thereby forming a solution comprising the metal cation in the solvent; and contacting the solution of comprising the metal cation with a cathode, thereby electrolytically precipitating the metal hydroxide from the solution. The stimulus may be chemical, mechanical, or both.

The present invention relates to the desulfurisation of lead-containing waste. In particular, the present invention relates to a method in which lead-containing waste is desulfurised to form a desulfurised lead-containing waste material which is suitable for recycling into lead or leady oxide. The method is particularly suitable for desulfurising lead-acid battery paste.

The present invention relates to the desulfurisation of lead-containing waste. In particular, the present invention relates to a method in which lead-containing waste is desulfurised to form a desulfurised lead-containing waste material which is suitable for recycling into lead or leady oxide. The method is particularly suitable for desulfurising lead-acid battery paste.

A system for treating tin smelting intermediate materials and method for treating the materials is disclosed. The system includes a fuming furnace, an electric settling furnace, a lean slag water quenching pool, a matte ladle, a pulverized coal injection system, a flue gas treatment system and a secondary air supply system; the fuming furnace is connected with the electric settling furnace, the pulverized coal injection system, the flue gas treatment system and the secondary air supply system respectively; the electric settling furnace is also connected with the slag-lean water quenching pool and the matte ladle respectively. The system and method disclosed by the disclosure can efficiently classify, separate and recover tin from other materials, solve the problems of difficult sales and transportation of complex tin-containing smelting intermediate materials and economic loss of discounted sales, and transform hazardous wastes into value-added valuable materials for comprehensive recovery.

A system for treating tin smelting intermediate materials and method for treating the materials is disclosed. The system includes a fuming furnace, an electric settling furnace, a lean slag water quenching pool, a matte ladle, a pulverized coal injection system, a flue gas treatment system and a secondary air supply system; the fuming furnace is connected with the electric settling furnace, the pulverized coal injection system, the flue gas treatment system and the secondary air supply system respectively; the electric settling furnace is also connected with the slag-lean water quenching pool and the matte ladle respectively. The system and method disclosed by the disclosure can efficiently classify, separate and recover tin from other materials, solve the problems of difficult sales and transportation of complex tin-containing smelting intermediate materials and economic loss of discounted sales, and transform hazardous wastes into value-added valuable materials for comprehensive recovery.

A hydrometallurgical method for simultaneously extracting zinc, lead, silver, iron and calcium from electric arc furnace dust (hazardous waste) produced by the steelmaking industry (steelworks), in the form of industrial products: zinc as zinc sulphate or zinc cathodes; lead and silver as a concentrate of lead and silver; iron as reduced elemental iron for return to the electric arc furnace; and, lastly, calcium as gypsum, without solid waste or liquid effluents being generated relates to the chemical nature of the electric arc furnace dust (complex oxides) changes to a sulfide complex, and eliminating the hazards associated with the generation of fugitive heavy-metal salts. In addition, the hydrometallurgical problem of low recovery of zinc and iron is solved. Consequently, hydrometallurgy is made easier and more environmentally friendly, as condensed water is used as a leachate, the condensed water being continuously regenerated by vacuum evaporation systems without generating effluents.

The invention relates to the field of efficient separation and recovery of bromine by full wet method, especially to a two-step separating method of bromide and recovery of lead and zinc from printed circuit board Incineration ash. It mainly includes first sodium hydroxide alkaline leaching, secondary sodium peroxide alkaline leaching, pH adjustment, separate lead and zinc, bromide evaporation and crystallization to recover crude bromide and other steps. Compared with traditional comprehensive recovery process of ash, the invention uses sodium hydroxide to dissolve bromide, lead and zinc, and uses the strong oxidation of sodium peroxide in alkaline environment, copper bromide and other bromine are oxidized and leached; through two-step method, the efficient leaching of bromine, lead and zinc is realized, silver and other precious metals are enriched at the same time. It is beneficial to subsequent recovery of precious metals and has the characteristics of short tail liquid discharge.

The invention relates to the field of efficient separation and recovery of bromine by full wet method, especially to a two-step separating method of bromide and recovery of lead and zinc from printed circuit board Incineration ash. It mainly includes first sodium hydroxide alkaline leaching, secondary sodium peroxide alkaline leaching, pH adjustment, separate lead and zinc, bromide evaporation and crystallization to recover crude bromide and other steps. Compared with traditional comprehensive recovery process of ash, the invention uses sodium hydroxide to dissolve bromide, lead and zinc, and uses the strong oxidation of sodium peroxide in alkaline environment, copper bromide and other bromine are oxidized and leached; through two-step method, the efficient leaching of bromine, lead and zinc is realized, silver and other precious metals are enriched at the same time. It is beneficial to subsequent recovery of precious metals and has the characteristics of short tail liquid discharge.

A system for recovering rare earth elements from coal ash includes a leaching reactor, an ash dryer downstream of the leaching reactor, and a roaster downstream of the ash dryer that is cooperatively connected to both the leaching reactor and the ash dryer. Coal ash is mixed with an acid stream such that rare earth elements present in the coal ash are dissolved in the acid stream, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. Mixing of the coal ash with the acid stream can occur in a leaching reactor and heating of the leachate can occur in a roaster. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.

The present invention relates to a method and apparatus for producing reduced iron from ironmaking dust which contains iron oxide which is generated at an ironmaking plant, takes note of the rotary kiln reduction method which does not require pretreatment of the dust, and has as its problem the pursuit of facilities which achieve further improvement of heat efficiency and stable operation.

To solve this problem, the present invention is characterized by heating and reducing carbon-containing shaped materials in a single closed space in which an internal heat type rotary kiln and an external heat type rotary kiln are arranged in series and including at least the insides of the two rotary kilns during which making the reduced exhaust gas which is generated at the external heat type rotary kiln burn inside of the internal heat type rotary kiln.