Study On The Adsorption Mechanism Of Pure Barite Minerals Under Microwave Action

Microwave heating is used in metallurgy,material preparation,mineral processing and other fields for its advantages of fast heating speed and high heating efficiency.In the process of barite flotation,microwave pretreatment can improve the flotation recovery,but the mechanism of microwave on flotation reagents and minerals is not clear.In this paper,sodium oleate was used as collector,and the flotation adsorption mechanism and flotation kinetics of barite pure minerals before and after microwave treatment were thoroughly discussed,which provided theoretical guidance for application of microwave heating technology in production process of barite flotation.Based on the flotation experiments of barite pure minerals,the effects of microwave on the flotation of barite were studied by means of solution chemical calculation,zeta potential,fourier infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）,surface tensiometer（STM）,contact angle analyzer（CAM）,ultraviolet spectrophotometer（L5）and other testing methods.At the same time,quantitative calculation of infrared spectrum fitting smoothing spectrum and second derivative spectrum as well as flotation kinetics analysis were carried out to explore the mechanism of microwave enhanced barite flotation.The flotation test of pure minerals showed that the flotation recovery increased respectively by 2.67%and 3.35%after microwave pretreatment of barite and deionized water;while the flotation recovery decreased respectively by 2.9%and 8.51%for the pulp and pulp with reagents.It indicated that microwave treatment of barite increased the flotation recovery rate（up to 95.27%）.The mechanism was that microwave heating improved the positive electrical property of barite surface,and the adsorption rate on the surface of barite was improved,thus improved the flotation recovery rate.FT-IR test results showed that before microwave pretreatment the barite interacted with sodium oleate by flotation,and the characteristic peak positions of reagents were all red shifted,indicating that chemisorptions of sodium oleate occurred on the surface of barite.However,in the process of barite flotation after microwave pretreatment,the characteristic peak positions of reagent was not red shift,but the peak strength increased significantly with the increasing of microwave treatment time,and the peak strength increased most obviously with the microwave treatment time of 60s.Fitting smoothing spectrum and second derivative spectrum calculation of the infrared spectrum after microwave action found that the peak areas at 2958cm^-1、2923cm^-1、2853cm^-1、1181cm^-1、1122cm^-1、1086cm^-1、982cm^-1、635cm^-1and 610cm^-1 increased to different degrees.In addition,the peak areas increased respectively by 1.84%,259.12%,761.15%,235.72%,145.61%,198.50%,641.16%,549.67%and 744.97%when treated with microwave for 60s,indicating that microwave pretreatment did not induce chemical reaction on the surface of barite.However,the chemisorption between sodium oleate and barite ore was strengthened,which makes the chemisorption between sodium oleate and barite surface more compact and the adsorption capacity larger.Flotation dynamics analysis showed that K value of the first order dynamics model is the most valuable of the four flotation dynamics models,and its fitting results can truly reflect the flotation results of barite before and after microwave treatment.