Provided are an extraction agent and extraction method that selectively extract and, at a low cost, recover gallium from an acidic solution containing gallium and zinc. The gallium extraction agent comprises an amide derivative represented by general formula (I). In the formula, R.sup.1 and R.sup.2 each indicate the same or different alkyl group, R.sup.3 indicates a hydrogen atom or an alkyl group, and R.sup.4 indicates a hydrogen atom or any given group, other than an amino group, bonded to the α-carbon as an amino acid. The general formula preferably has a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit, or an N-methylglycine unit. By extracting gallium from an acidic solution containing gallium and zinc by means of solvent extraction using the extraction agent, it is possible to selectively extract gallium.

Provided are an extraction agent and extraction method that selectively extract and, at a low cost, recover gallium from an acidic solution containing gallium and zinc. The gallium extraction agent comprises an amide derivative represented by general formula (I). In the formula, R.sup.1 and R.sup.2 each indicate the same or different alkyl group, R.sup.3 indicates a hydrogen atom or an alkyl group, and R.sup.4 indicates a hydrogen atom or any given group, other than an amino group, bonded to the α-carbon as an amino acid. The general formula preferably has a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit, or an N-methylglycine unit. By extracting gallium from an acidic solution containing gallium and zinc by means of solvent extraction using the extraction agent, it is possible to selectively extract gallium.

The invention relates to a method for producing solid particles from an inorganic solid containing at least one alkali metal and/or alkaline earth metal, comprising at least the following steps: a) providing the inorganic solid containing at least one alkali metal and/or alkaline earth metal; b) extracting the at least one alkali metal and/or alkaline earth metal from the inorganic solid containing alkali metal and/or alkaline earth metal to obtain an extract containing the alkali metal and/or alkaline earth metal and an alkali metal-depleted and/or alkaline earth metal-depleted residue; c) separating the extract from the residue; d) processing the residue to obtain the solid particles, wherein at least one of the processing steps is selected from a group comprising transporting, filling, packaging, washing, drying, adjusting the pH value, separating according to a mean grain size and/or mass and/or density, adjusting a mean grain size, magnetic separating, calcining, thermal rounding and surface coating.

Provided is a production method and a production apparatus that increase a throughput of nickel sulfate per equipment. A first dissolution step I of introducing a nickel briquette, sulfuric acid, and water to a leaching tank (1) and dissolving the nickel briquette to obtain a primary nickel sulfate solution, and a second dissolution step II of introducing the primary nickel sulfate solution and additionally introducing a nickel briquette to a leaching adjustment tank (2) and dissolving the additionally introduced nickel briquette with free sulfuric acid in the primary nickel sulfate solution to obtain a nickel sulfate solution are executed in this order. With the leaching adjustment tank (2) having a role as a concentration adjustment tank that increases a nickel concentration and decreases a free sulfuric acid concentration, and the leaching tank (1) supplied with the sulfuric acid and the water in addition to the nickel briquette, a continuous dissolution is achievable without increasing a retention time and without unnecessarily enlarging the equipment.

Provided is a production method and a production apparatus that increase a throughput of nickel sulfate per equipment. A first dissolution step I of introducing a nickel briquette, sulfuric acid, and water to a leaching tank (1) and dissolving the nickel briquette to obtain a primary nickel sulfate solution, and a second dissolution step II of introducing the primary nickel sulfate solution and additionally introducing a nickel briquette to a leaching adjustment tank (2) and dissolving the additionally introduced nickel briquette with free sulfuric acid in the primary nickel sulfate solution to obtain a nickel sulfate solution are executed in this order. With the leaching adjustment tank (2) having a role as a concentration adjustment tank that increases a nickel concentration and decreases a free sulfuric acid concentration, and the leaching tank (1) supplied with the sulfuric acid and the water in addition to the nickel briquette, a continuous dissolution is achievable without increasing a retention time and without unnecessarily enlarging the equipment.

The invention relates to a system for neutralizing asbestos, said system comprising a mobile neutralization unit (200) comprising: an asbestos waste sorting module (225), an asbestos grinder (255) and a hot acid bath (250) for rendering asbestos inert.

Preferably, the asbestos waste sorting module comprises: a window with glove boxes; and a conveyor for transporting the asbestos waste in front of the window.

In embodiments, the system comprises a means for containing the atmosphere within the mobile neutralization unit and/or the hot acid bath (250) of the mobile neutralization unit (200) comprises sulfuric acid.

A hydrometallurgical process for the treatment of polymetallic ores and sulphide concentrates of copper and zinc, and by-products of lead and zinc from smelting plants, treated independently and/or as mixtures thereof, which contain relevant amounts of lead, copper, zinc, iron, gold and silver, such as the matte-speiss mixture of lead foundries, and copper cements from the purification processes of electrolytic zinc plants. Thee process allows the recovery of metallic copper, zinc, copper as copper and zinc basic salts, which may be hydroxides, carbonates, hidroxysulphates or mixtures thereof; the production of stable arsenic residues; and the effective and efficient recovery of Pb, Au and Ag as a concentrate of lead sulphide and/or lead, Au, and Ag sulphate.

A hydrometallurgical process for the treatment of polymetallic ores and sulphide concentrates of copper and zinc, and by-products of lead and zinc from smelting plants, treated independently and/or as mixtures thereof, which contain relevant amounts of lead, copper, zinc, iron, gold and silver, such as the matte-speiss mixture of lead foundries, and copper cements from the purification processes of electrolytic zinc plants. Thee process allows the recovery of metallic copper, zinc, copper as copper and zinc basic salts, which may be hydroxides, carbonates, hidroxysulphates or mixtures thereof; the production of stable arsenic residues; and the effective and efficient recovery of Pb, Au and Ag as a concentrate of lead sulphide and/or lead, Au, and Ag sulphate.

A process to significantly improve the copper chemical leaching process for primary and secondary minerals, using calcium chloride including the agglomeration, curing, and leaching with a high content of chloride, iron and copper stages. The mineral is then washed with a low concentration of copper and a high concentration of acid, where the impregnated copper is extracted from the pit and wherein a recirculated solution is used in the agglomeration stage.

A process to significantly improve the copper chemical leaching process for primary and secondary minerals, using calcium chloride including the agglomeration, curing, and leaching with a high content of chloride, iron and copper stages. The mineral is then washed with a low concentration of copper and a high concentration of acid, where the impregnated copper is extracted from the pit and wherein a recirculated solution is used in the agglomeration stage.