Diagramme de phases du système ternaire KCl-FeCl3-H2O. Isothermes 15 et 30 °C

The phase diagram of the ternary system KCl-FeCl3-H2O was determined at 15 and 30°C by conductimetric and analytical methods. The solubilitie curves are given. In this temperature range, we have observed the crystallisation fields of KCl , FeCl3.6H2O and of a double salt 2KCl.FeCl3.H2O.The composition of the isothermal invariant points (liq. ↔ KCl + FeCl3.6H2O) and (liq. ↔ FeCl3.6H2O + 2KCl.FeCl3.H2O) is determined

Structure – Properties study of Na2O–CaO–PbO–P2O5 metaphosphate glasses

International audienc

Équilibre solide-liquide du système quaternaire K

Le diagramme d'équilibre liquide-solide du système K+, Na+, Fe3+/Cl- - H2O a été établi à 15 et 30°C à l'aide de la méthode conductimétrique. Les méthodes des ensembles et des restes ont été utilisées de façon complémentaire. Les courbes à teneurs en eau constante sont données, les lignes monovariantes sont représentées en projection orthogonale, de même que les points invariants quaternaires. Pour les deux isothermes, on observe les domaines de cristallisation de KCl, NaCl, FeCl3.6H2O et 2KCl.FeCl3.H2O

Study of novel oxyfluoronitride bioglasses

International audienceBioglasses are used as bone substitutes and prosthetic coatings. Following implantation, they are predisposed to generate a series of physicochemical reactions at the glass-bone interface. Bioglasses with molar composition: 55SiO2–8.5CaO–31.5Na2O–5CaF2 have been synthesized and characterized. However, because of their poor strength, doping with nitrogen was performed on these glasses to increase their mechanical properties. The Young's elastic moduli, Vicker's microhardnesses, and the fracture toughnesses were measured and observed to increase linearly with nitrogen content in each of these systems. These results are consistent with the incorporation of nitrogen into the glass structure in three-fold coordination with silicon. Fluorine addition significantly decreases the thermal property values but the mechanical properties of these glasses remain unchanged with fluorine. The characterization of these N and F substituted bioglasses using 29Si MAS NMR have shown that the increase in rigidity of the glass network can be explained by the formation of SiO3N, SiO2N2 tetrahedra and Q4 units with extra bridging anions at the expense of Q3 units. The bioactivity of the glasses has been evaluated by soaking them in simulated body fluid (SBF) and showed that all oxyfluonitrides glasses are bioactives. Cytotoxicity tests based on different concentrations of bioglass powders in a cell growth environment have been also showed that they are not cytotoxi

Thermal treatment of moroccan phosphogypsum

Phosphogypsum (PG) is produced as a by-product during treatment of phosphate rock with sulphuric acid to produce phosphoric acid according to the following simplified reaction: Ca_{10} (PO_2 )_6 F_2 + 10H_2 SO_4 {\rm{ }} + {\rm{ }}20H_2 O{\rm{ }}\buildrel {70{\rm{ }}\`a {\rm{ }}80^\circ C} \over \longrightarrow {\rm{ }}6H_3 PO_4 {\rm{ }} + {\rm{ }}2HF{\rm{ }} + {\rm{ }}10(CaSO_4 .2H_2 O) Minerai Phosphogypse PG is mainly CaSO4·2H2O but also contains impurities such as free phosphoric acid, phosphates, fluorides and organic matter that adhere to the surface of the gypsum crystals. Phosphogypsum is discharged directly to the Sea or into the natural evaporation ponds. Previous studies have focused on reducing impurity levels in PG. Phosphogypsum impurities can be removed by simple techniques. Washing with water removes the soluble impurities. By cons, other contaminants (radioactive elements, heavy metals ...) a specific treatment method required a complex technique where the treatment is likely to be expensive. In this study, we studied purification of phosphogypsum using water and the thermal behavior of the natural gypsum and Moroccan phosphogypsum to calculation of parameters for drying and dehydration reactions. Also, the effects of different heating temperature on the course of dehydration are investigated

Remineralization of permeate water by calcite bed in the Daoura's plant (south of Morocco)

To face water shortage and to fight drought, the National office of Water and Electricity (ONEE) carried out a program aiming at constructing several desalination stations of seawater in the South of Morocco. However, the final product water after desalination (osmosis water) has turned out to be unbalanced and has an aggressive character. Therefore, a post-treatment of remineralization is necessary to recover the calco-carbonic equilibrium of water and to protect the distribution network from corrosion degradation. Thereby, our work aims to examine the performance of the remineralization used in Daoura plant by the calcite bed in the absence of carbon dioxide CO2 (without acidification), we have followed many parameters indicating the performance of this technique adopted such as pH, TAC (hydroxide, carbonate and bicarbonate content), Ca content, Langelier saturation index (LSI), Larson index (LR). The results obtained show that this technique adopted in Daoura plant brings to water back its entire calco-carbonic balance to measure up to the Moroccan standards of drinking water. Generally, the exploitation of the calcite bed technique for remineralization is simple, easy and it does not require any major efforts or precautions

Evaluation of remineralization performance of osmosis water on the calcite bed at a laboratory scale

International audienc