Effects Of Macromolecular Organic Depressants On Flotation Behavior Of Apatite And Calcium Carbonate Minerals And The Mechanism

Phosphate ore resources are strategic resources for China.It is worth paying attention to the rational development and utilization of phosphate ore.It is difficult to separate apatite from calcium carbonate minerals such as dolomite and calcite in the flotation process of calcareous magnesite phosphate ore.The effects of carboxylated chitosan,sodium alginate,acacia gum,calcium lignin sulfonate and other macromolecular organic depressants on mineral floatability were studied by pure mineral flotation experiments.The contact angle test,adsorption amount test,infrared spectrum test,and X-ray photoelectron spectroscopy test were used to study the action mechanism of macromolecular organic depressants on the surface of apatite,dolomite,and calcite.The subject research provides a certain basic theoretical reference for the efficient separation of apatite and calcium carbonate minerals.The main research results are as follows:The flotation results of pure minerals show that apatite,dolomite,and calcite have good floatability under the alkaline conditions and are similar.Floatation separation of apatite,dolomite,and calcite cannot be achieved without the use of depressant.When no depressant is added,Within the range of flotation particle size,mineral floatability decreases with the ore particle size decreases.Between pH=8¹0,carboxylated chitosan,sodium alginate,pectin,sweet potato gum,acacia gum,and calcium lignosulfonate all have little effect on the floatability of apatite.Dolomite and calcite are strongly depressed.The contact angle test results show that under the conditions of pH=9,sodium oleate1·10^-4mol·L^-1,carboxylated chitosan,sodium alginate,pectin,arabin gum and calcium lignosulfonate can sharply reduce the surface contact angle of dolomite and calcite,and greatly reduce the hydrophobicity.The effect of these five macromolecular organic depressants on the contact angle of the apatite surface is relatively weak,and it still maintains good surface hydrophobicity.The adsorption test results show that the adsorption amount of the five macromolecular organic depressants on the surface of apatite,dolomite,and calcite increases with the increase of the amount,and the adsorption amount on the surface of apatite is less than that on the surface of dolomite and calcite.The results of infrared spectroscopy and XPS analysis showed that at pH=9,the effects of carboxylated chitosan,sodium alginate,pectin,and acacia gum on the surface of apatite were hydrogen bonding,the effect of calcium lignosulfonate and apatite is through the chemical action of-SO₃^-and Ca²⁺.At pH=9,carboxylated chitosan,sodium alginate,pectin,and gum arabic can all chelate with Ca²⁺on the surface of dolomite through-COO^-,and calcium lignosulfonate interacts with Ca²⁺through-SO₃^-.At pH=9,the adsorption mode of carboxylated chitosan and sodium alginate on the surface of calcite is coexistence of hydrogen bonding and chemisorption;the adsorption of pectin and acacia gum on the surface of calcite is through chelation of-COO^-and Ca²⁺;The adsorption form of calcium lignosulfonate on the surface of calcite is the chemical action of-SO^-and Ca²⁺.