Construction And Analysis Of Flotation Reagent Adsorption Equilibrium Model Based On Classical Oxidized Mineral Site Interaction

Over the years,the low carbon and high efficiency utilization of mineral resources,mainly co-associated complex ores,has put forward higher requirements on the comprehensive performance of flotation reagent system.However,the traditional flotation theory lacks scientific description on mineral surface action sites.It will seriously hinder the flotation process development,if the flotation adsorption behavior cannot be accurately predicted,in which the affinity and selectivity of reagents onto each mineral surface are considered as core flotation mechanisms.Based on the interfacial double layer theory and flotation solution chemistry,the flotation equilibrium model of ions/reagents adsorption was constructed to calculate some flotation adsorption intrinsic constants.Adopting these constants,both electrical properties of mineral surface and adsorbed amount of reagents can be forecasted,forming the kernel algorithm of mineral flotation process prediction system.This method can quickly and accurately analyze the adsorption amount of each mineral to each reagent and its floatability under each condition,which is of great significance for reagent adsorption mechanism study on mineral surface.The main results are as follows:（1）There are some mathematical equilibrium relationships during ions/reagents adsorption onto oxidized mineral surface in flotation including species,charge,hydrolysis,mass and dissolution.Based on electrical double layer and flotation solution chemistry theory,the flotation ions/reagents adsorption equilibrium was constructed through considering solid-liquid interface influence factors.Using the results of mineral potentiometric titration and reagent adsorption tests as initial data,a mathematical matrix with variable parameters was derived for Newton Raphson iterative calculation,which can output mineral flotation intrinsic constants such as active site density N_s,（de）protonation reaction constant K_t1/K_t2,and reagent adsorption constant K_f.（2）The active site distribution onto mineral surface was quantitively analyzed and verified from different ways according to the constructed model.Taking diaspore-kaolinite and spodumene-feldspar as two flotation systems,the protonation/deprotonation constant of each site was calculated including≡Al OH onto diaspore,≡Al OH,≡Si OH and permanently negative charge site≡X^-onto kaolinite,≡Al OH and≡Si OH onto spodumene and feldspar.Besides,site density can also be achieved.These constants do not vary with the pulp environment,so that the distribution of mineral surface sites and the degree of reaction with protons under arbitrary conditions can be favorably quantified.For spodumene and feldspar,there is much Si and Al transferring from mineral surface into solution and mainly existed as H₂Si O₃and Al³⁺.The quantified mineral surface simulation results were successfully verified by Zeta potential test and AFM force curves in combination with DLVO theory,guaranteeing the reliability and rationality of the model construction for proton reaction processes.（3）The complexation process was also quantified based on the multi-location interaction between different kinds of flotation collectors and surface sites of diaspore and kaolinite.Sodium oleate（NaOL）,cetyltrimethylammonium bromide（CTAB）,and benzhydroxamic acid（BHA）were applied as single anionic positive flotation collector,single cationic reverse flotation collector,and mixed NaOL/BHA collectors,respectively,in diaspore-kaolinite flotation system.The complexation equilibrium constants of each collector with≡Al OH onto diaspore and≡Al OH,≡Si OH and≡X^-onto kaolinite were put forward.For diaspore,the≡Al OH reaction constants with NaOL and CTAB are 13.55 and-2.17,respectively,while the constants of≡Al OH and≡Si OH with NaOL are11.76 and 10.35,respectively,which were significantly smaller than that of diaspore,indicating the higher affinity of diaspore for NaOL.The complexation reactions of≡Al OH,≡Si OH and≡X^-with CTAB are-3.25,-2.84 and 3.90,respectively.The contents of adsorbed sites were as followed:≡XRNH₃>≡Si ORNH₃>≡Al ORNH₃.There are two kinds of complexation ways for BHA adsorption,containing mononuclear and binuclear.It has been proved that the configuration of bidentate binuclear seems to be closer to the experimental results.（4）The metal-group collector of Ca-NaOL was also simulated and calculated in spodumene and feldspar flotation system based the established adsorption equilibrium model.Single NaOL adsorption reaction constants with Al and Si sites on the spodumene surface are 9.33and 10.31,respectively,while the corresponding values of feldspar are 9.81and 10.80,separately.Four types of product sites were generated for Ca-NaOL adsorption,including≡Al OCa OL,≡Al OHCa（OL）₂,≡Si OCa OL,≡Si OHCa（OL）₂.The complexation constants on the spodumene surface are1.37,10.24,2.04,12.06,and the relative values on the feldspar surface are0.76,9.05,1.33,10.66,respectively.Based on these constants,various surface site distributions can be quantified and expressed,with the Al site having a higher affinity for NaOL.（5）The series intrinsic constants of ion/reagent adsorption reactions were verified by pH conditions,mixed mineral system and mixed reagent system respectively,which proved the rationality and validity of the model construction.Meanwhile,the spatial coordination configuration changes of Al and Si sites on the spodumene and feldspar surfaces were revealed via XPS and EXAFS analysis.Finally,the adsorption density of product sites was correlated to mineral floatability,quantitively explaining the effect of selective adsorption behavior on flotation separation efficiency.Furthermore,a universal set of equations for collector adsorption in flotation systems was complied,which laid an important foundation for constructing a mineral floatability prediction system.