Research On The Inhibitory Performance And Mechanism Of Polymer Agents On Fluorite And Calcite In Scheelite

Polymeric depressants are an important direction in the field of flotation reagents,and have always been valued by scholars at home and abroad.Currently,Polymeric depressants have been widely reported,such as non-ionic polymer depressants tannin,dextrin,arabic gum,anionic polymer depressants carboxymethyl cellulose,Gul gum,sodium polyacrylate,However,the mechanism of adsorption of polymer depressants is very complicated,because the polymer is composed of many chain-like structures,and there will be random curls in the solution.The adsorption of polymeric depressants on minerals surface depend on its properties,such as functional group type,molecular weight distribution,viscosity,spatial configuration and surface charge density of ionic polymer and so on.In view of the characteristics of China's mineral resources,some of the specific polymer agents can selectively inhibit the waste rocks,making the polymer depressants have a broad application prospects in the ore dressing.In this paper,sodium polyacrylate,carboxymethyl cellulose and polyacrylamide were selected as depressants of scheelite,fluorite and calcite.Through the single mineral flotation test,under the sodium oleate system of collector,the effect of pulp pH,type and dosage of polymeric depressants on the flotation inhibition of scheelite,fluorite and calcite was investigated.Then,the effects of metal ions,scrubbing time and addition of sodium hexametaphosphate on the inhibition performance of sodium polyacrylate were investigated further.The selectivity of sodium polyacrylate and its mixture with sodium hexametaphosphate to scheelite,fluorite and calcite are can obviously confirmed.With the help of contact angle,Zeta potential measurements,adsorption capacity determination and infrared spectroscopy,the effects of sodium polyacrylate and its mixed with sodium hexametaphosphate on the surface wettability,surface zeta potential,the adsorption amount of sodium oleate on scheelite,fluorite and calcite.The minerals,obtained from scheelite plant in Yunnan,the results of flotation were obtained,sodium hexametaphosphate has a selective inhibition effect.further verify the effect of new depressant?sodium polyacrylate and phosphate mixed?on scheelite,fluorite and calcite at room temperature.The results of single mineral flotation test shown that:when sodium oleate was selectedascollector,sodiumpolyacrylate,carboxymethylcelluloseand polyacrylamide will inhabit scheelite,fluorite and calcite at a large extent,but only sodium polyacrylate have some selective inhibition on scheelite,fluorite and calcite.However,the recovery of scheelite reduced to only about 78%;sodium polyacrylate and sodium hexametaphosphate mixed was used as inhibitor in next test.Compared with the inhibitor PA-Na,PA-Na and sodium hexametaphosphate mixed has selective inhibition on fluorite and calcite.PA-Na and phosphate mixture ratio of 3:1,the optimum separation index was obtained.When the pH was 9 and the dosage was25 mg/L,PA-Na and phosphate mixed had the optimum separation index for calcium minerals,the recoveries of scheelite,fluorite and calcite were 80.33%,43.67%and45.33%,respectively.The metal ions Pb²⁺and Ca²⁺had a weak influence on the inhibition of sodium polyacrylate,of which the inhibition of Pb²⁺was stronger than that of Fe²⁺and Ca²⁺.Scrubbing time have little effect on the inhibition of sodium polyacrylate.PA-Na and phosphate mixed was depressant,The separation of scheelite from fluorite and calcite is better than that of PA-Na.Compared with the scheelite recovery of single mineral flotation,artificial mixed ore flotation conditions scheelite recovery decreased by about 10%,probably the addition of calcite and fluorite,the Ca components of minerals surface mutually migrate in water medium,resulting in similar mineral surface properties,and affecting the flotation recovery of scheelite.A practical mineral flotation test was conducted on the scheelite from Yunnan Province.Sodium polyacrylate+sodium hexametaphosphate as inhibitor at a dosage of 25 g/t,after one stage rougher flotation,five stages of cleaner and three stages of scavenger,the scheelite concentrate was obtained with 53.26%WO₃ and a recovery of59.75%,indicating that new depressant?sodium polyacrylate and phosphate mixed?has a selective inhibition effect on scheelite,fluorite and calcite.With the aid of the contact angle,the zeta potential,the adsorption capacity and the infrared spectrum,the inhibitory mechanism of sodium polyacrylate and its mixed PA-Na with phosphate on scheelite,fluorite and calcite was studied.Sodium polyacrylate have selective inhibition on scheelite,fluorite and calcite,changing the wettability of the mineral surface,the zeta potential and affect the adsorption amount of sodium oleate on the minerals surface.Compared with PA-Na,PA-Na and phosphate mixed reduced the contact angle of fluorite and calcite to a greater extent,but had less influence on the contact angle of scheelite,indicating that PA-Na and sodium hexametaphosphate mixed was better than PA-Na.Compared with PA-Na,the addition of PA-Na and sodium hexametaphosphate mixed makes the surface potentials of fluorite and calcite more negatively shifted,and the order of shift intensity are fluorite>calcite>scheelite.Compared with the PA-Na inhibitor,PA-Na and sodium hexametaphosphate mixed significantly reduced the adsorption amount of sodium oleate on the surface of fluorite and calcite,while the adsorption of sodium oleate on the scheelite decreased slightly.Infrared spectroscopy tests showed that it is likely that phosphate was added to PA-Na as a chain transfer agent,effectively reducing the length of the chains in the polymer by reversible addition-fragmentation chain transfer polymerization?RAFT?,altering the molecular weight distribution of the polymer,Further enhancing the selectivity of PA-Na to scheelite,fluorite and calcite.Through the research in this paper,the inhibitory mechanism of macromolecule inhibitors on three calcium-containing minerals is preliminarily revealed,and some reference significance for analyzing the inhibitory mechanism of polymeric depressants is provided.