The Research On Formation And Regulation Of Over-stable Foam In Reverse Flotation Of Silicate For Collophane Ore With Ether Amine As Collector

Phosphorus is an indispensable element for the growth of all crops and has a unique position in national food security.The resources reserve of phosphate in china is abundant,but more than 90%is low-grade ore.Due to the reduction of high-grade phosphate ores,the utilization of complex ultrafine phosphate ore with a high content of silicate has become highly concerned.Flotation has been commercially used as a mian method for removing silicate from phosphate for siliceous phosphate ore,including anionic flotation and cationic reverse flotation.The former technology is mature and its index is good,but the complicated reagent regime and high heating cost is a major problem in phosphate ore processing.The latter technology does not require heating and the reagent regime is simple,however,the foam of flotation is over stable and not easily broken.Thus,the conception on formation and regulation of over stable foam in reverse flotation of silicate for phosphate ore with cationic collector was raised in the paper.The two-phase foam properties of 3-?decyloxy?propan-1-amine(C₁₀A),3-?dodecyl-loxy?propan-1-amine(C₁₂A),3-??8-methylnonyl?oxy?propan-1-amine (YC₁₀A),N¹-?3-?decyloxy?propyl?propane-1,3-diamine(D₁₀A)and N¹-?3-??8-methyl-nonyl?oxy?propyl?propane-1,3-diamine(YD₁₀A)were studied at the beginning of the paper.The results indicated that the adsorption capacity of alkyl ether diamine(YD₁₀A)with branched chain structure was the lowest at gas-liquid interface,and the molecular area was the largest.Thus,the foam capacity and foam stability of the YD₁₀A system was the lowest due to the loose arrangement of YD₁₀A molecules at liquid film of foam.The order of foam capacity and foam stability was C₁₂A>C₁₀A>D₁₀A>YC₁₀A>YD₁₀A.In addition,the effect of liquid properties of YD₁₀A solution on two-phase foam properties was also investigated.The results showed that the foam capacity of YD₁₀A system increased with increase of temperature,while the foam stability showed opposite trend.The foam capacity and foam stability decreased with pH value increasing and reached minimum value at pH=10.When adding the electrolyte,the adsorption capacity of YD₁₀A at the gas-liquid interface enhanced and the foam stability increased.The effects of four typical mineral particles in phosphate ore on foam stability were studied,and effects of the electrolyte on the stability of the three-phase foam were also investigated.The adsorption of YD10A on the surface of four mineral particles is a monolayer physisorption.The surface potential and hydrophobicity of mineral particles increased with increase of YD₁₀A concentration.The adsorption of hydrophobic mineral particles on the bubble surface could enhance the foam stability.For the collophane,dolomite and calcite,the stronger hydrophobicity of particles,the stronger ability of stabilizing the foam.For the quartz,the stability of the three-phase foam increased firstly and then decreased with the increase of hydrophobicity,reaching a minimum value when contact angle was 90°.The hydrophobicity of the quartz particles was more important to the foam tability than the surface potential.Additional,the smaller the particle size of minerals,the stronger ability of stabilizing the foam.For the four kinds of minerals with the same particle size,the order of the capacity to stabilize the foam was calcite>dolomite>collophane>quartz.The stability of three-phase foam increased significantly with addition ofAlCl₃andFeCl₃.The laboratory flotation experiments on the real siliceous phosphate ore were carried out,and developed pre-desliming-flotation desliming-cationic reverse flotation technology for separation silicate from phosphate ore.Pre-separation of dolomite in phosphate ore can effectively prevent fine particles of carbonate to stabilize foam in flotation of silicate using ether diamine as collector.The pre-desliming and flotation desliming could remove most slime?-10?m?from raw ore of cationic reverse flotation,which could reduce the stability of flotation foam significantly.Addition of defoamer TOP into flotation pulp could regulate the foam properties,which decreased the foam stability and improved the foam brittleness.It has been proved that pre-desliming-flotation desliming-cationic reverse flotation technology was suitable for siliceous phosphate ore,the high-quality concentrate containing 33.24%P2O5 can be obtained when the flotation foam stability meet the requirements of industrial production.