Study On Settlement Mechanism Of Fine Kaolinite Tailing Ballasteded Flocculation By Quartz Carrier

Clay minerals are widely found in the field of mineral processing,especially in the tailings processing of various mineral resources.The presence of a large number of fine-grained kaolinite particles is reasearch difficult and hot issue which restricts tailings treatment efficiency and tailings dewatering.The existing sedimentation dewatering treatment process containing fine-grained kaolinite tailings is mainly based on flocculation and sedimentation,but there are disadvantages such as large consumption of chemicals,complicated equipment,high process requirements,and ineffective effects.Today’s flocculation technology based on coarse sand in tailings has been widely used in water treatment and oil sand tailings treatment abroad,but its related mechanism of action has rarely been reported,and carrier flocculation technology is also used in China’s mining industry.There are few applications.In order to solve the above problems,the coarse size quartz is used as the carrier,and the flocculation and sedimentation of the fine-grained kaolinite tailings is carried out by the carrier flocculation method.The particle size gradation rule of the flocs is explored,and the high-frequency flocculant is studied in the carrier quartz and fine grain.The action mechanism of the surface of the granitic particles and the rapid sedimentation of the fine-grained kaolinite tailings are achieved by the strengthening of the carrier sedimentation.Firstly,the surface microstructure of fine-grained kaolinite and quartz carrier particles was studied by X-ray diffraction(XRD),X-ray fluorescence spectroscopy(XRF),Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM)and BET specific surface area and pore size distribution.The surface functional group of the fine-grained kaolinite pure mineral is a hydrophilic functional group with a scaly structure on the surface,and the micropores are mainly composed of type II pores,which determines its high specific surface area and porosity.The industrial kaolinite particles have a rougher surface,a larger specific surface area,and an increased number of class I pores in the micropores.The surface of the quartz carrier particles is relatively smooth and the porosity is extremely small.As the particle size of the quartz decreases,its specific surface area increases rapidly,but the porosity does not change substantially.In the exploration of the flocculation law of pure minerals of fine-grained kaolinite,the sedimentation law of fine-grained kaolinite during flocculation and sedimentation and the influence on the water quality of supernatant were studied.It was found that calcium ions and aluminum ions with more positive charge had a significant improvement on the sedimentation rate of the final flocs and the supernatant turbidity.Appropriate increase in temperature contributes to an increase in sedimentation rate,but deteriorates supernatant turbidity.The sedimentation law and particle size grading characteristics of the ballasteded flocculation were studied.Through the sedimentation test of carrier-enhanced flocculation,the flocculation behavior and sedimentation performance of carrier-reinforced flocculation were studied from three aspects of tailings particle size composition,electrolyte and temperature: the final floc size formed by the increase of particle size of the loading body The larger the effect of the electrolyte on the final floc size,sedimentation rate and supernatant turbidity,is positively correlated with the positive charge of the metal ion load.In the gradation particle size of the final floc,the content of large-sized flocs of >100μm was the highest in the presence of calcium ions,and the medium-sized floc content of 10-100μm was the highest in the presence of aluminum ions.Among them,calcium ion contributed the most to the sedimentation rate,and aluminum ion contributed the most to the supernatant turbidity.The effect of temperature on the sedimentation characteristics of the flocculation of the carrier and the turbidity of the supernatant is basically consistent with the flocculation law of the pure mineral of kaolinite.In the study of the mechanism of ballasteded flocculation and sedimentation,the adsorption of PAM on different mineral surfaces and the calculation of thermodynamic parameters were studied by total organic carbon analyzer(TOC).The study firstly explored the adsorption of quartz carriers and fine-grained kaolinite under different electrolyte and temperature conditions.The adsorption and adsorption rates of quartz were lower than that of kaolinite,and the adsorption of quartz and kaolinite increased slightly with temperature.Then the thermal analysis was carried out.The analysis showed that both quartz and kaolinite accorded with the Langmuir isotherm adsorption equation.The adsorption of quartz is an endothermic reaction process,and the adsorption of kaolinite is an exothermic reaction process.After the temperature rises appropriately,the PAM adsorbed by the quartz increases,and the ability to capture the fine-grained kaolinite is enhanced,so that a larger particle size floc can be formed to facilitate the sedimentation rate.The feasibility of flocculation of fine-grained kaolinite by quartz carrier was theoretically verified.The mechanism of action between particles was analyzed by quantum chemical calculations and classical DLVO calculations.The binding energy of PAM to quartz was calculated to be-16.93 KJ/mol,and the binding energy to the surface of kaolinite 001 was-33.18 KJ/mol,which is consistent with the standard entropy calculation results of quartz and kaolinite,indicating PAM molecules.The binding on the quartz surface is lower than that of kaolinite,which is more conducive to the stretching of PAM molecules,which verifies the feasibility of quartz-based floc growth.The theoretical calculation of DLVO on the interaction between particles shows that the electrostatic force repulsive force between quartz and kaolinite particles after PAM adsorption is enhanced,and the van der Waals potential energy is reduced,resulting in a decrease in the absolute value of total potential energy,but still exhibits rejection.Potential energy.This indicates that the carrier quartz flocculated fine-grained kaolinite is mainly realized by the bridge action of the flocculant.A ballasteded flocculation experiment based of this study was carried out to simulate the actual fine-grain kaolinite tailings.Compared with the conventional test,the flocculation settling rate of the carrier flocculation intensification test was increased by 11.21 times,and the supernatant turbidity was maintained at the low turbidity state,which is 10 to 30 NTU.It achieves rapid and efficient settlement of fine-grained kaolinite.The paper contains 73 figures,39 tables,and 180 pieces of references.