Abstract: The invention concerns a treatment process with a starting aqueous phase (SAP) containing titanium and sulfuric acid produced by the attack of sulfuric acid on titaniferous ores of the type in which the following steps are used: an extraction step in which the starting aqueous phase is placed in contact with an organic extraction phase (OEP) containing one or a plurality of organophosphorus compounds, by means of which an organic phase containing titanium and sulfuric acid (OP) is obtained; then, a regeneration step in which the organic phase containing titanium and sulfuric acid (OP) is regenerated by contact with an aqueous regeneration phase (ARP0), by means of which a regenerated aqueous phase (RAPf) containing titanium is obtained; characterized in that it includes in additional step in which all or part of the regenerated aqueous phase (RAPf) is placed in contact with an organic washing phase (OWP), by means of which a treated aqueous phase (TAP) containing titanium is obtained.

Abstract: A composition having sodium bicarbonate, sodium carbonate, and ammonia in the form of ammonium salts is formed by heat treating ammoniacal bicarbonate at a temperature between 20 and 150° C. A method of using the composition includes reacting the composition with a flue gas containing HX acids, where X represents halogens, compounds of the SOx type, or mixtures thereof, or the flue gases may contain NOx compounds.

Abstract: A method for removing contaminants, such as sulfur dioxide, mercury and hydrochloric acid, out of flue gases is provided, said method including the steps of: treating the flue gases with a reagent, such as sodium carbonate, sodium bicarbonate and ammonium salts or mixtures thereof; selectively dissolving the sodium phosphates produced thereby in water; separating out the solids remaining in suspension in the solution; and crystallizing the purified sodium sulphate present in the above-mentioned solution. The sodium sulfate can be upgraded in glass working furnaces. The reagent can be obtained by heating an intermediate solution containing sodium bicarbonate; sodium carbonate; ammonium bicarbonate and ammonium carbonate, which was obtained from the Solvay process for manufacturing sodium carbonate.

Abstract: The invention relates to the use of barium sulphide or strontium sulphide for the removal of heavy metals in industrial acidic solutions.The invention is applicable to the purification of contaminated acids, in particular of spent battery acid, or of industrial solutions of titanyl sulphate.