Selecting And Breeding Of Microorganism For Dephosphorization Of Phosphorus-rich Manganese Ore

Most part of manganese ore in China contains a rather high grade of phosphorus minerals, which are harmful to iron and steel metallurgy.Traditional dephosphorizations have many disadvantages, such as huge power consumption, and serious environmental pollution. Therefore, microorganism dephosphorization was developed due to its effective utilization of resource, low environmental pollution and less power consumption.One kind of phosphate-solubilizing microorganism was investigated. The experiment foundation of new dephosphorization technique was analyzed.Several strains were separated from the soil sampled from Xiangtan manganese mine. Finally 9 strains are selected by the means of phosphorus hole and liquid culture. The most effective strain for dephosphorization, named as P69 in this paper, was identified as Penicillium Genus.Strain UM-5 was obtained from P69 through mutagenesis by ultraviolet radiation and microwave treatment, and its P-decomposing in medium was 27.78 mg/100 mL, 1.18 times more than that of P69. From the result of generation experement, it indicated that strain UM-5 has a high hereditable 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 initial pH of the medium, rotating speed of the flakes, culture temperature, inoculation capacity. The optimum culture conditions of strain UM-5 were found by single factor tests and composition of the culture mediun tests. The optimum culture conditions of UM-5 were as follows, sucrose 28g/L,KNO₃ 3.5 g/L, Ca₃(PO₄)₂ 0.9g/L,FeSO4 0.01g/L,KCl 0.5g/L , MgSO₄ 0.5g/L , initial pH 5.0, roating speed 140r/min, cultural temperature 35℃, inoculation capacity 10mL. Under this culture condition, the p-content in the medium is up to 45.74 mg/100 mL and the dephosphorization efficiency reached to 50.8%.Strain UM-5 was domesticated by metal ions and phosphorus-rich manganese ore. The phosphorus-rich manganese ore was treated by domesticated strain. And the influencing factors of the dephosphorization efficiency ware studied. The experimental results showed that optimum conditions of dephosphorization for phosphorus-rich manganese ore were as follows: particle size -74μm, pulp consistency 15%,liquid volume in flask 100mL. The dephosphorization efficiency of the domesticated strain reached to 77.8%,and the ratio of phosphorus to manganese dropped to 0.0024 from 0.0109 in ore.The result is satisfactory for metallurgy.