Study On Preparation Of Hydrotalcite And Zeolite From Magnesium Slag

In this paper,magnesium slag is used as raw material.According to its composition characteristics,hydrochloric acid is used as medium.The process of elemental leaching from magnesium slag-prepared multicomponent hydrotalcite by filtrate-prepared zeolite material by filter slag was proposed.The research on acid leaching of magnesium slag,preparation of hydrotalcite and zeolite is emphasized,the adsorption properties of methyl orange and ammonia nitrogen were investigated by using hydrotalcite and zeolite as adsorption materials.The main research contents and conclusions are as follows:（1）By studying the influences of stirring speed,initial concentration of hydrochloric acid,liquid-solid ratio,reaction temperature and time on the leaching process of Ca²⁺,Mg²⁺,Al³⁺,Fe³⁺and other metal ions in magnesium slag,the optimal technological conditions for acid leaching of magnesium slag were obtained as follows:the stirring speed was 500 r/min,the hydrochloric acid was 2 mol/L,the liquid-solid ratio was 15:1,the reaction temperature and time were 90℃and 180 min,respectively.The kinetic equations of Ca²⁺,Mg²⁺,Al³⁺and Fe³⁺were established and fitted to Avrami equation.（2）The influences of pH,crystallization time and temperature on the growth of Ca-Mg-Al-Fe HTlc crystal and the adsorption kinetics of methyl orange were studied with the filtrate after acid leaching of magnesium slag as raw materials,the results show that Ca-Mg-Al-Fe HTlc samples have higher crystallinity and regular morphology when pH=11.9,crystallization temperature 150℃and time 16 h;The sample was used as adsorbent to absorb methyl orange aqueous solution.When the amount of adsorbent added was 0.4 g/L,the concentration of methyl orange solution was 100 mg/L,the volume was 100 m L,the adsorption temperature and the time were30℃and 360 min,respectively.the adsorption capacity reaches 203.96 mg/g;The adsorption process of methyl orange by Ca-Mg-Al-Fe HTlc fits the pseudo-second-order kinetic model.At the same time,the sample characterization before and after adsorption also confirmed that the adsorption of methyl orange by Ca-Mg-Al-Fe HTlc includes two cases:interlayer anion replacement and outer surface adsorption.（3）The effects of mass ratio of filter slag to sodium metabaluminate,concentration ofNa OH,crystallization temperature and crystallization time on the synthesis of NaA-type zeolite and the adsorption kinetics of ammonia nitrogen were studied using the filter slag after acid leaching of magnesium slag as raw material,When the mass ratio is 2:3,the alkalinity is 4 mol/L and the crystallization temperature and time are80℃and 6 h,respectively,the crystalline phase pairs of NaA zeolite are complete and the crystallinity is high.Taking the sample prepared as adsorbent,ammonia nitrogen simulated wastewater solution.When the adsorbent was 2 g/L,the concentration of ammonia nitrogen solution was 100 mg/L,the volume was 100 m L,the adsorption temperature and time were 25℃and 150 min,repectively,the adsorption capacity was20.2 mg/g;The adsorption course of ammonia nitrogen by NaA zeolite fits the pseudo-second-order kinetic model.The main reason that NaA zeolite can adsorb ammonia nitrogen is ion exchange.