Experimental Study On Synergistic Activation Of Low-grade Phosphate Rock By Ultrafine Grinding And Activator

China’s phosphate rock resources are abundant,but high-grade phosphate rock reserves are lack.As a result,the development and utilization of low-grade phosphate rock resources have become the key point.In this thesis,the medium-to-low grade phosphate rock powder in a certain area of Hebei Province was used as the research object to carry out the optimization test of the process parameters of superfine grinding / activator synergistic activation of phosphate rock.To investigate the changes in the morphology,crystal structure,specific surface area,and surface free energy of phosphate rock powder and their relationship with the citrate solubility of phosphate rock during the ultrafine grinding / activator synergistic activation.The test results showed that the low-grade phosphate rock powder is activated by planetary ball mill grinding.Under the optimal process parameters of dry milling,the effective phosphorus content is 7.29%.The rate of citrate acid soluble is 61.68%.The median diameter of ultrafine phosphate rock powder is 2.71μm.With the optimum technological parameters of wet grinding,the effective phosphorus content is 8.38%.The rate of citrate acid soluble is70.91%.The median diameter of ultrafine phosphate rock powder is 1.71μm.Compared with dry grinding,wet grinding is more favorable to activate phosphate powder.After adding complex activator synergistic activation,the effective phosphorus content is 9.98%.The rate of citrate acid soluble is 84.43%.The median diameter of ultrafine phosphate rock powder is 1.69μm.Compared with the change of properties of phosphate powder before and after the addition of activator,the citrate solubility of the phosphate rock can be effectively improved after the addition of the activator.The grinding time was extended from 0min to 180 min.The coarse-grained phosphate rock powder was gradually pulverized into fine particles.The apatite crystallinity decreased significantly and the amorphousness increased.The specific surface area and surface free energy of the phosphate rock powder increased accordingly,and the phosphorus content increased.Both the specific surface area and the surface free energy of the ore powder have a strong positive correlation with the citrus dissolution rate.With the help of the established mathematical model,the corresponding citrus dissolution rate can be calculated by measuring the specific surface area of the ground product.The medium and low grade phosphate rock powder can be directly used as phosphate fertilizer after being activated by superfine grinding,which provides support for the sustainable use of phosphate rock resources in China.Figure44;Table3;Reference 51...