A hydrometallurgical treatment was applied to the Hajar Mine Cooper Concentrate (HMCC), Morocco, containing approximate to 28.1% copper (the major copper mineral phase is chalcopyrite. CuFeS2), approximate to 26.3% iron, approximate to 5.8% zinc, approximate to 1.9% lead, approximate to 33.7% sulphur, and small amounts of silver (269 g/t) and nickel (219 g/t). Three acid media were used: ferric sulphate in sulfuric acid, ferric sulphate in hexafluorosilicic acid, and a hexafluorosilicic acid-nitric acid mixture. The results show that when a ferric sulphate reagent is used, in H2SO4, as well as in H2SiF6, media, dissolution of copper and iron do not exceed 30%, because of the formation of a passivation layer on chalcopyrite particles, whereas zinc is dissolved at about 90%. The final solid leachate residue represents 75% by weight of the initial solid and remains rich in copper (approximate to 28%) and iron (approximate to 25%). However, under strong acid and oxidizing conditions, in the hexafluorosilicic acid-nitric acid mixture, the dissolution of copper is more efficient, although it is nonselective, (92% Cu. 89% Fe, 98% Zn). The solid leachate residue represents only 40% by weight of the original sample, and assays 5.9% Cu, 7.3% Fe, 0.2% Zn, 4.1% Pb, and 56.4% S-total. Mineralogical characterizations of the leachate solid residues show the formation of both elemental sulphur and a Cu1-xFe1-yS2-z layer on the surface of the nondissolved chalcopyrite.

In order to understand the long-term behavior of pollutants in the solidified/stabilized (S/S) Municipal Solid Waste Incineration (MSWI) fly ashes using cement, raw MSWI fly ashes, as well as aged and fresh S/S samples were studied. Materials were examined through chemical analyses, leaching and permeability tests, petrographical observations, X-ray diffraction, EDS-based TEM and SEM. Drastically high amounts of Cl− and Pb are leached from the solidified/stabilized MSWI fly ashes, due to both the presence of soluble minerals and a network of micro-cracks leading to a very low cohesion and an impermeability loss of the material. Beyond portlandite and calcite, the main major minerals identified in aged S/S MSWI fly ashes are hydrocalumite, ettringite and ordered silicate-hydrates mostly free of heavy metals. The ordered silicate-hydrates are missing in fresh samples. The large variety of heavy metal-bearing compounds is distributed between inherited stable phases (metallic alloys, spinels, glasses, refractory oxides, titanates, phosphates, etc.) and inherited or neo-formed unstable phases (amphoteric metals, hydroxides, carbonates, chlorides, chromates, etc.). Combining the results from major phase identification and heavy metal speciation, it emerges that Zn and partly Cr are trapped in stable compounds whereas Cl−, SO42− and Pb mineral species are characterized by an instability which is not enhanced by maturation. The high Cl− activity and the high alkali conditions play a critical role in Pb-forming minerals and, more generally, the evolution of major mineral phases and the differentiation of heavy metal-bearing species in huge monolith are governed by an exposure to temperatures close to 100 °C for several years.

Une étude comparative de calcination en four rotatif, pendant 30 min, et en four éclair (Flash) pendant 4 s, est réalisée en vue de décarbonater le phosphate sédimentaire d'Akashat. Il en résulte que la calcination dynamique en four Flash à 1000 °C donne des résultats plus intéressants que la calcination en four rotatif à 950 °C, tant au niveau de la qualité du phosphate calciné-lavé qu'au niveau de la fabrication de l'acide phosphorique. En effet, elle permet d'éliminer 57,5 % du CO2 total, tout en sauvegardant 65,2 % du CO2 apatitique, d'obtenir un calciné-lavé titrant 29,8 % en P2O5 et seulement 0,17% en MgO. L'attaque sulfurique de ce calciné-lavé est aisée: le rendement de lixiviation atteint 97,1 %; la filtration est rapide (70 s), compte tenu de la morphologie trapue des cristaux de phosphogypse et de la faible teneur en MgO; et le taux de corrosion est faible (0,07 mm/an).

Ion flotation of molybdenum in sulfuric acid leach solutions of uranium was performed using a flotation column (75 mm diameter, 3 m height). Three bubble generators (Microcel, Flotaire and Imox) were tested to achieve the flotation of the precipitate formed between Mo and alpha-benzoine oxime. The studied parameters were bubble diameter, energy dissipation and initial Mo concentration. From the lab and pilot plant results (>95% Mo recovery), was estimated the possibility of determining the number of flotation column which would be needed for purification of solution coming from three industrial plants.