Surface Interaction Mechanism Of Dodecylmorpholine With Sodium Chloride,Potassium Chloride And Carnallite

Based on the analysis of the development situation,and especially the technique and mechanism of potassium salt flotation process,this work is mainly focus on investigating the basic properties of flotation reagent dodecylmorpholine(DMP).Experimental results of static adsorption,flotation were carried out through various instrumental analyses.And also,the mechanism of flotation and interaction between DMP and soluble salts were further studied.1.The main components of industrial grade DMP were analyzed by Scanning Electron Microscope(SEM),Energy Dispersive Spectrometer(EDS),X-ray Diffraction(XRD),Fourier Transform Infrared Spectroscopy(FT-IR)and Gas Chromatography Mass Spectrometry(GC-MS).The results showed that two kinds of impurities were contained in the industrial grade DMP:one is the residue of solid catalyst from the synthesis process,and the other one is the liquid target product DMP and little by-product from the reaction.2.One technique was investigated and established to detect the concentration of industrial grade DMP in aqueous solution by using UV-vis spectrophotometry.This technique is easy and quick,and unaffected by temperature,p H and common ions from brine.Under proper conditions,like solution temperature(20-60?),p H(0.62-4.32),concentration of cations(K+,Na+,Mg2+=0-0.6 mol/L)and anions(CO32-,HCO3-,Cl-,Br-,I-,SO42-),the concentration of DMP can be detected without effect.This method can measure DMP properly with a detection limit of 0.3 mmol/L,RSD of 0.100%-0.612% and the recovery of 95%-104%.3.The surface tension of DMP aqueous solution was determined by surface tension method at different inorganic salt ion concentration and p H.The critical micelle concentration(CMC)was calculated based on the relevant data.The results revealed that the CMC value decreased with the increase of solution p H,concentration and valence of cations.The analysis of mechanism indicates that the influence of the cations on CMC is not only related to the shielding effect between the hydrated cations and surfactants,but also the salt-out effect of cations.4.The adsorption behavior of DMP on the surface of different inorganic salts was studied by the static adsorption method.The effects of inorganic salt particle size and DMP initial concentration on the adsorption behavior were also investigated.The sequence of adsorption ability for DMP on different inorganic salts is: NaC l >> KC l > carnallite.The adsorption amount decreased with the increase of NaC l particle size and increased with the increase of NaC l concentration.However,the size of KCl and concentration of DMP had no influence on the adsorption amount of DMP on KCl.This could be physical adsorption between DMP and KCl or NaC l according to the results of FT-IR.5.The capture behavior of DMP in different solutions and ultrasonic pretreatment effect were investigated by flotation experiments.The results showed that DMP had the best collectivity capacity for NaCl,followed by KC l,but could not collect carnallite in the single salt and its saturated solution.The collectivity capacity of DMP for NaCl and KC l both decreased in the carnallite/NaC l-saturated magnesium chloride flotation system.After ultrasonic pretreatment,the surface of particles become rougher,and NaC l and KCl can be collected by DMP better.