The disclosure relates to a plant for thermal treatment of solid material to decrease the content of heavy metal elements. The plant comprises one reactor for heating the solid material, which is arranged to have both an oxidizing atmosphere and a reducing atmosphere, and the plant includes a hot gas generator, which is arranged to provide hot gas to the reactor. The disclosure also relates to a method for thermal treatment of solid material and to a method for producing fertilizer precursor.

A pyro-metallurgical process for producing at least one non-ferrous metal or a compound thereof, wherein said metal is selected from the group consisting of arsenic (As), antimony (Sb), lead (Pb), cadmium (Cd), mercury (Hg), silver (Ag), tin (Sn), nickel (Ni), and zinc (Zn), and wherein at least one raw material is fed into a rotary kiln, wherein said at least one raw material comprises at least said metal, and wherein said raw material is heated to produce a volatized material, in which the non-ferrous metal or compound thereof is produced from the volatized material, in which process a magnesium-based additive, is additionally fed in the rotary kiln in an amount of between 0.5 wt. % and 9.5 wt. % relative to the total weight of said raw materials, which magnesium-based additive is heated together with said raw material to produce at least the volatized material and a solid product, thereby counteracting ring formation in the rotary kiln.

A method for reprocessing nitride spent nuclear fuel in molten salts comprises chlorinating the fuel in a melt of a mixture of alkali and/or alkaline earth metal chlorides containing cadmium dichloride. The chlorination is carried out in an apparatus for reprocessing nitride spent nuclear fuel using an inert gas atmosphere The apparatus has a heated zone containing a reactor with molten chlorides and nitride spent nuclear fuel submerged therein, and also a cold zone arranged under the reactor. In the chlorination process, the zone of the apparatus containing the reactor is heated to a temperature greater than 700 C., the nitride spent nuclear fuel is kept in the melt until fully chlorinated. The cold zone of the apparatus is used for crystallizing metallic cadmium which forms during the chlorination.

A method for reprocessing nitride spent nuclear fuel in molten salts comprises chlorinating the fuel in a melt of a mixture of alkali and/or alkaline earth metal chlorides containing cadmium dichloride. The chlorination is carried out in an apparatus for reprocessing nitride spent nuclear fuel using an inert gas atmosphere The apparatus has a heated zone containing a reactor with molten chlorides and nitride spent nuclear fuel submerged therein, and also a cold zone arranged under the reactor. In the chlorination process, the zone of the apparatus containing the reactor is heated to a temperature greater than 700 C., the nitride spent nuclear fuel is kept in the melt until fully chlorinated. The cold zone of the apparatus is used for crystallizing metallic cadmium which forms during the chlorination.

A process of extracting metals from a wet mass includes a step A of concentrating the metals in a carbonaceous solid with a thermochemical treatment of the wet mass, with the ancillary production of a treatment gas; a step B of thermochemical decomposition of the carbonaceous solid in an atmosphere constituted by an operating gas which contains oxygen in substoichiometric quantity to carry out the thermochemical decomposition in order to promote a combination of the metals with substances present in the carbonaceous solid to form salts and others solid compounds and to concentrate the latter in residual ashes of the carbonaceous solid at the same time providing for the formation of a combustible synthesis gas comprising hydrocarbons from the carbonaceous solid; and a step C of extraction of the metals from the ashes produced.

A process, for the selective heavy metal removal from iron- and/or steelmaking flue dust, including steps of: preparing a feedstock (FS) by blending or mixing a chloride precursor material (CPM) and ironmaking and/or steelmaking flue dust including heavy metals (ISFD), the heavy metals including Pb and Zn and optionally Cd; in a first reaction step in a first reactor reacting the CPM with the ISFD by thermal treatment of the FS at a temperature in a range of 700 C. to 950 C. removing at least 70 wt. % of Pb from the ISFD; in a subsequent second reaction step in a second reactor further reacting the CPM with the ISFD by thermal treatment of the feedstock FS at a temperature in a range of 850 C. to 1200 C.; and obtaining a solid material after the second reaction step. The invention also relates to a plant implementing the process.

A process, for the selective heavy metal removal from iron- and/or steelmaking flue dust, including steps of: preparing a feedstock (FS) by blending or mixing a chloride precursor material (CPM) and ironmaking and/or steelmaking flue dust including heavy metals (ISFD), the heavy metals including Pb and Zn and optionally Cd; in a first reaction step in a first reactor reacting the CPM with the ISFD by thermal treatment of the FS at a temperature in a range of 700 C. to 950 C. removing at least 70 wt. % of Pb from the ISFD; in a subsequent second reaction step in a second reactor further reacting the CPM with the ISFD by thermal treatment of the feedstock FS at a temperature in a range of 850 C. to 1200 C.; and obtaining a solid material after the second reaction step. The invention also relates to a plant implementing the process.