Experimental Study On Rare Earth Flotation Of Bayan Obo Weak Magnetic Intensity Tailings

Rare earth is an important strategic resource in China and a essential material for industry.With the accelerate of national economy and industry development,the demand for high-grade rare earth concentrates is becoming larger and larger in the market.However,due to the complexity of ores and the problems of beneficiation process,the utilization rate of rare earth concentrates in Bayan Obo ore process is low,and there are many impurities in rare earth concentrates,which cause industrial pollution in the smelting process.In this paper,starting from the optimization of rare earth flotation process,combined with the study of process mineralogy and flotation experiments of real rare earth minerals.The optimum flotation conditions and process flow are determined by single variable controlled conditional experiment on grinding time,pulp consistency,temperature,pH value,flotation time and dosage of reagents.Finally,through the flotation behavior of rare earth pure minerals.Fourier transform infrared spectroscopy（FTIR）,Zeta potential and solution chemistry were analyzed to study the flotation mechanism of minerals.The main contents and conclusions of this paper are as follows:The REO grade of weak magnetic tailings is 9.66%,and the relative content of valuable elements is slightly higher than the average content of raw ore in Bayan Obo mining area.Relatively high mineral compositions are fluorite,iron,rare earth minerals and gangue minerals,dolomite and barite.Rare earth minerals mainly consist of hamartite and monazite,accounting for 13.58%of the total proportion.The ratio of hamartite to monazite is about 3:1.The proportion of hamartite is obviously increased relative to the ores in shallow mining.The main minerals are finer in size,and the dissociation degree of rare earth minerals is very high is 87.28%.Most of the other rare earth minerals exist with silicate,iron ore and fluorite.At the same time,direct flotation of rare earth from weak magnetic tailings is feasible.It is necessary to inhibit barite,fluorite and pyrite in flotation process to ensure the grade and recovery of rare earth concentrate.In this paper,silicate as inhibitor and LF-P86 as collector were used to optimize the conditions of roughing of Baiyun Obo weak magnetic tailings.The optimum conditions and dosage of roughing are as follows:grinding fineness of low magnetic tailings-74μm accounting for 88.2%,flotation temperature is 65℃,flotation concentration is47%,dosage of Na₂CO₃ is 1 kg/t（pH=9）,dosage of inhibitor is 3.6 kg/t,dosage of collector is 1.35 kg/t,dosage of foaming agent is 0.5 kg/t,flotation time is 5minutes.Finally,roughing products with rare earth concentrate grade of 27%and recovery of 81%can be obtained.The flotation process is determined as one roughing,three refining and one sweeping.The grade of rare earth concentrate is 60.72%,the recovery rate is 48.75%,the grade of rare earth secondary concentrate is 27.01,the recovery rate is 19.49,and the comprehensive recovery rate is 68.24%.The results of flotation mechanism showed that the concentration of Ce（OH）₃,the dominant component of rare earth hydrolysis when the pH value was 9,so the collector’s collecting effect was directly related to the concentration of Ce（OH）₃.At the same time,the main hydrolysates of silicate hydrolysis were Si（OH）₄ and SiO（OH）₃^-,and the concentration of Si（OH）₄ was higher than SiO（OH）₃^-,and Si（OH）₄ was the dominant component;The collection of LF-P86 is mainly due to the fact that the two O atoms in the structure are located on the same side with similar distances,which has advantages for the formation of O-O five-membered ring chelate structure.Actually,collection is collector anions and rare earth cations form stable five-membered ring chelates.The analysis results of Zeta potential and Fourier transform infrared spectroscopy（FTIR）by flotation of rare earth pure minerals show that LF-P86 has advantages in forming chemical adsorption of hydrogen bond and coordination bond on the surface of bastnaesite,and the pHysical adsorption plays an auxiliary role,while the pHysical adsorption is dominant on the surface of monazite.