Selection And Cultivation Of Dephosphorus Strains On High Phosphorus Oolitic Hematite Ores

In the past 10 years, the iron ore market situation has changed dramatically, especially because of Chinese and other Asian emerging markets economic growth, which pushed the increase in world steel consumption. Therefore, the demand for iron ore and iron ore prices are rising. This makes use of hydrometallurgical methods to reduce phosphorus impurities in high phosphorus iron ore with the economic feasibility. In China, High phosphorus hematite untapped iron ore resources, the traditional dressing methods have drawbacks, and microbial hydrometallurgical technology has attracted special concern, because of its environmental protection effects.Through a series of tests, phosphate solubilizing bacteria were broadly screened in soil samples from around the campus and the high phosphorus oolitic hematite ore. 8 strains with better dephosphorization were selected. TX3,which is a fungal strain, dephosphorization effect is the best in the 8 strains. After further identification, confirming that the strain is Aspergillus. Spp. Strain TX2 also has good performance in dephosphorization which is also fungus, identification confirmed that the strain is Penicillium spp. KX10 was also found to have some solubilizing effect, and the strain was identified as Cronobacter spp.Bacteria cultivated through the high phosphorus hematite ore gradual acclimation had a good growth activity.In the leaching test, the acclimated strains TX2, TX3 adaptive capacity in high phosphorus iron ore has been strengthened, and its pH dropped faster, and the leaching rate in 10 days had increased, compared with the rate before the acclimation.Take TX3 as the original strain, was under UV mutagenesis. Mutagenesis strain UV7-4 showed the best phosphate solubilization effect. The dissolved phosphate reached 47.72mg/100mL,1.15 times than TX3. Through the experimental determination UV7-4 had good genetic stability.An orthogonality test of 4 factors and 3 levels was carried out.The results indicated that the sequence according to their affecting ability was carbon source, nitrogen source, inoculum, and initial pH of the medium, The optimum culture conditions of strain UV7-4 were found by single factor tests and composition of the culture mediun tests. The optimum culture conditions of UV7-4 were as follows, carbon sucrose 30g/L, (NH4)2SO42.5g/L, FeSO40.01 g/L, NaCl 0.1g/L, KCl0.2g/L, MgSO4 0.1g/L,,roating speed 150r/min, inoculation capacity 107. Under this culture condition,the p-content in the medium is up to 51.69 mg/100 mL in 9 days.Based on the findings, microbial dephosphorization of high phosphorus hematite was closely related with their functions of organic acids production. With pH values higher than 2.57 in the environment, insoluble phosphates are difficult to dissolve. Phosphorus-limited environment, microorganisms will take the initiative to attach to the ore particles on the surface of phosphorus particle, and breeding, thus changing the pH value of micro-environment around the phosphorus-containing particles. Reduction of pH value of the micro-environment makes a large number of free H+ to attack insoluble phosphates, and phosphorus in iron ore is dissolved to the environment. Tank simulation by Cronobacter spp. strain KX10 phosphorus leaching experiments, in 9 days, dephosphorization was 72%.