Abstract: A method for the treatment of jarosite and other residues of the zinc and lead production industry, including the following steps: thermal treatment of the residues, at a temperature between 500° C. and 700° C., to obtain the evaporation of the imbibition water and the demolition of the jarosite molecule, resulting in the development of SO3 and in the removal of OH? groups to give additional water in the gaseous phase, and resulting in the obtainment, from the recondensation of these components, of an aqueous solution of diluted sulfuric acid, and with the simultaneous formation of a solid fraction composed of iron(III) oxide, zinc, lead, silver, copper sulphates and other minor elements; and then steps for acid leaching, a refining treatment; and purification to obtain solubilization of iron(III); separation of the solubilized iron(III) from the silica, which remains insolubilized; precipitation of iron(III) to obtain iron oxide pigment.

Abstract: Multistage process for the preparation of a concentrate of metals, rare metals and rare earth metals from residues of alumina production by Bayer process (red mud), or from materials with a chemical composition similar to red mud, and multistage process for separating the elements of interest, transforming them into single products to be re-used in the Bayer process and/or sending them to the respective reference markets. The sole FIGURE appended shows the simplified block diagram of the invention, in terms of its most extensive definition.

Abstract: The subject of the invention is a process for the extraction, from bauxite, from red mud resulting from the processing of bauxite, and from chemically similar materials, of products of industrial interest, like sodium, iron, gallium, aluminum, titanium and silicon, separated from each other in chloride form. The process involves the melting of the to be treated material and the blowing in the melted bath of chlorine or chlorine in situ generating compounds, and the controlled cooling of the gaseous flow exiting from the melted bath for the selective condensation of chlorides of the elements of interest. The FIGURE shows a block diagram of a particular embodiment wherein the melting is carried out in a transferred arc plasma reactor.

Abstract: An improved process is described for the removal of organic pollutants from soil by extraction with a lipophylic solvent, wherein the improvement consists in the fact that the purified soil is treated with water to remove the residual solvent. This process allows the residual solvent to be completely removed from the purified soil enabling it to be re-inserted into the environment, with a low energy consumption and a greater guarante of safety in the running of the plant.

Abstract: An improved process is described for the removal of organic pollutants from soil by extraction with a lipophylic solvent, wherein the improvement consists in the fact that the purified soil is treated with water to remove the residual solvent. This process allows the residual solvent to be completely removed from the purified soil enabling it to be re-inserted into the environment, with a low energy consumption and a greater guarante of safety in the running of the plant.