Preparation of ultrafine iron phosphate micro-powder from phosphate slag

In this experiment, ultrafine iron phosphate micro-powder was prepared by hydrothermal method which used phosphate slag as an iron source. The effects of reaction temperature, surfactants type and amount on its particle size were explored. The samples were characterized by using Malvern Laser Particle Size Analyzer (MS2000), X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).The results showed that at 160 °C, 1 wt%CTAB, monoclinic iron phosphate micro-powder was obtained with an average particle size about 0.4 μm which also has a good dispersion in aqueous solution.

Removal of lead from crude antimony by using NaPo3 as lead elimination reagent

In order to solve the shortcomings when removing lead from crude antimony in the traditional antimony smelting, a new process was provided using NaPO3 as lead elimination reagent to yield phosphate slag, and it was removed by floating on the surface of the liquid antimony. Reaction mechanism was clarified by using the TG-DTA and XRD techniques and single factor experiments of removal lead from crude antimony were engaged. The results show that PbO and NaPO3 begin endothermic reaction at 863K (590?C), and the reaction mainly form NaPb4(PO4)3 and NaPbPO4 below 1123K (850?C) and above 1123K (850?C), respectively. Sb2O3 and NaPO3 start the reaction at 773K (500?C) and generate an antimonic salt compound. The reaction product of the mixture of PbO, Sb2O3 and NaPO3 show that NaPO3 reacted with PbO prior when NaPO3 was insufficient, amorphous antimony glass will be generated only when NaPO3 was adequate. Single factor experiments were taken with NaNO3 as oxidizing agent under argon, effect of reaction time, reaction temperature and dosage of NaPO3 and NaNO3 on smelting results. The average content of lead in refined antimony was 0.05340% and 98.85% of lead were removed under optimal conditions; the content of lead in antimony have meet the requirements of commercial antimony.

Effect of Ground Phosphate Slag on the Resistance to Chloride Ion Penetration of Concrete

The permeability resistance of concrete with ground phosphate slag(GPS) against chloride ion penetration was tested according to ASTM1202 and by nitrogen adsorption method. Test results show that by adding ground phosphate slag to concrete, the chloride diffusion coefficient of concrete decreases, and the permeability resistance of concrete against chloride ion penetration increases with improvement of its pore structure. The pores in concrete are refined and the percentage of the pores with diameter less than 20nm in concrete increases. The improvement of pore structure of the concrete by ground phosphate slag is much better than that by the ground granulated blast furnace slag or fly ash, while the addition is 30 percent. The ability of additive to improve the permeability resistance of concrete against chloride ion penetration is in following order: fly ash > ground phosphate slag > ground granulated blast furnace slag.