| Abstrakt: |
In order to reduce the unwanted effects due to a solid genesis during the phosphoric acid concentration process and for eventual valorization on an industrial scale and uses of this material. A natural material, extracted from the soil, in the Doukkala region of Morocco, is used for 29% P2O5phosphoric acid desulphation with a simple protocol, which can be inserted into the manufacturing process. The physico-chemical analysis of this material was performed by XRD, FTIR, TGA-DTA, XRF and SEM–EDX. The XRD shows that the natural material consists mainly of calcite (Ca0.97Mg0.03CO3), quartz (SiO2) and a low clay fraction (illite). Different bonds and groups (Si–O–Si (Al), CO32−) were highlighted by FTIR analysis. The TGA-TDA reveals the decomposition of calcite. XRF and EDX analysis clearly indicate high quantity of calcium and weak amount of Mg element. They showed that it contains mainly 92wt% of Calcite with very low magnesium content, 7 wt% of quartz and 1 wt% of clay-type illite. The modelling of this protocol, by the methodology of experimental designs with the strategy of complete factorial designs with three factors [amount of natural material (Q), temperature (T) and time (t)] and two levels, is statistically validated (R2= 99.94%) and has shown that temperature and time do not significant effect and the amount of material has an effect on the reduction of sulphate ions. To avoid an excess of calcium (Ca/SO4= 1), the optimum quantity of material is 26.08 g per litre of acid, which reduced the rate of solid formed to 63.64% during concentration of the 29% acid in P2O5. Such an improvement will undoubtedly have interesting consequences for the improvement of productivity and the protection of industrial equipment. |
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