The Experiment Study On The Best Preparation Process, Micro-characterization And Adsorption Property Of Bentonite And Steel Slag Composite Particle

In order to solve the problem synchronously that acidity and heavy metal ions in acid mine drainage,the study developed a kind of bentonite composite particles which could both remove heavy metal ions and reduce the acidity,the study explored the preparation technology,mechanism and adsorption performance to provide the theory basic for preparation and application of the water treatment material that efficient and low consumption.On the base of the alkaline materials and additive agent selection,through single factor and multi-factors orthogonal experiment,the study reveals the main influencing factor of the preparation technology of the composite particle using the poor analysis and variance analysis method:roasting temperature>roasting time>the ratio of bentonite and steel slag≥the dosage of Na₂CO₃.So as to the optimum process conditions were as follows:roasting temperature is 500℃,roasting time is 60 min,the ratio of bentonite and steel slag is 5:5,the additive agent account for 5%of the total mass.The total alkalinity of the best composite particle releases 35.5125mg/g,it can buffer pH and loss rate is 1.18%.The best composite particle adsorbs Fe²⁺,Mn²⁺,Cu²⁺,Zn²⁺,the equilibrium adsorption quantity can reach at 23.97、16.77、27.56、22.59mg/g.It is a good water treatment material.Through the micro-characterization SEM,XRD,FT-IR of different state of adsorption materials,high temperature roasting only disperse the water and impurity in the interlayer to magnify the interlayer spacing.The layer spacing of the composite particles is from 1.287nm to 1.549nm.There is enough space to adsorb heavy metal ions.The layered structure is obvious,the surface is rough and surface area is enormous.It has surface adsorption capacity powerfully.The steel slag and addition agent don’t change the structure of montmorillonite.The combination of steel slag,montmorillonite and addition agent and generates NaAlSi₂O₆、NaFeSi₂O₆、Ca₃Fe₃（SiO₄）₃ et al.The composite particles have alkaline.The surface of composite particles is wrapped heavy metal ions after adsorb Fe²⁺、Mn²⁺、Cu²⁺、Zn²⁺to make the content of heavy metal ions increase.So the best particles have the adsorption-coagulation heavy metal ions and reduce the acidity.The study of adsorption performance of best composite particle show:when the100mL simulate acid mine drainage which the concentration of Fe²⁺、Mn²⁺、Cu²⁺、Zn²⁺are 100、35、20、25mg/L respectively,pH is 3-4,put 1g adsorption in it.The concentration of Fe²⁺、Mn²⁺、Cu²⁺、Zn²⁺in the rest of the solution can reach at 6.79、4.44、0、2.58mg/L at 240min,the pH is 7-8.The concentration of the water and pH meet the national standard.And the study reveals the best composite particles of Fe²⁺、Mn²⁺、Cu²⁺、Zn²⁺adsorption are more inclined to BET multilayer adsorption,set up the BET multilayer adsorption isotherm and secondary adsorption dynamics model..