Mineral Processing Technology Of Low-grade Manganese-phosphate Ore

Manganese ore and phosphate ore, as important mineral resources, have a widerange of applications in the industry. The proven phosphate and manganese resourcesare rich in Maliu region of Shaanxi Ziyang. The Mn-bearing ore consists ofmangandolomite, rhodochrosite and manganocalcite, and the phosphorous oreconsists of fine particle collophanite and few crystalline apatite. Although there is fewparagenesis between manganese ore and phosphate ore, the thin layers of the two orebodies are in lamination with the dolomitic shale bed. Due to the difficulty to minethe manganese ore and phosphate ore alone, the mining can only be done in mixedform. And the mixed mining leads to a mixed ore, combining many kinds of minerals,eventually resulting in the difficulty of efficient recovery of Mn and P. To solve thisproblem, this paper starts from the properties of the mixed ore to determine theoccurrences of Mn and P, therefore obtains an optimum process to recover Mn and Pcomprehensively through a series of tests.The process mineralogy studies show that the mixed ore, with a complexcomposition, has a MnO content of8.82%and a P2O5grade of9.82%. Andcollophanite and mangandolomite are the target minerals, while quartz, dolomite andcalcite are the main gangue minerals.The optimum grinding fineness of the magnetic separation of Mn and P from themixed ore is54.55%-0.074mm. With periodic pulsating high gradient magneticseparator, the obtained manganese ore is of19.91%MnO and0.78%P2O5,meanwhile the phosphate ore is of14.16%P2O5,2.87%MnO. A manganese ore withMnO content19.96%, P2O5grade9.82%and a phosphate ore with P2O5grade13.84%, MnO content2.75%can also be obtained by using a DLS vertical ringpulsating high gradient magnetic separator.The magnetic separation tests of the obtained manganese ore show that with agrinding fineness of93%-0.038mm, as the result of heterogeneous condensation ofthe fine particles in the pulp, the concentrate can only obtain a MnO content of31.33%with a recovery of61.43%through direct magnetic separation. As the addition of dispersant (water glass or sodium hexametaphosphate) before magnetic separation,there is a little improvement of concentrate MnO grade, but a sharp decline ofrecovery. After flocculation magnetic separation, the concentrate is of about32%MnO content and61.43%recovery. Under a grinding fineness of75.45%-0.074mm,after a direct magnetic separation closed-circuit process of one roughing, oneconcentration and one scavenging, the concentrate can obtain MnO32.66%with ayield of49.77%, a recovery of82.30%, a P2O5content of0.18%and a P/Mn ratio of0.0031. Meanwhile the MnO content of the tailing is6.88%. The coarse grindingcondition can achieve a better result compared to the fine grinding condition thoughthe target mineral is not completely liberated with the gangues.The flotation tests of the obtained phosphate ore show that under the optimumgrinding fineness of90.53%-0.074mm, after a direct-reverse flotation closed-circuitprocess, the concentrate can obtain P2O531.58%with a yield of34.11%and arecovery of78.83%, meanwhile the P2O5content of two tailings is4.96%and5.33%respectively.A manganese concentrate with MnO content19.96%, P2O5content0.18%and aphosphate concentrate with P2O5grade29.52%, MnO content0.80%, MgO content0.97%can be obtained after the whole magnetic separation flotation flow sheet. Thecomprehensive recovery of Mn is63.83%, that of P is86.6%. The result indicating anefficient recovery of Mn and P provides a scientific basis the exploitation andutilization of the Manganese and phosphate ore resources in this region.