高铝粉煤灰碱溶法制备氢氧化铝的研究  

The preparation of aluminum hydroxide from high-alumina fly ash based on alkali dissolution method

作　　者：苏双青[1,2] 马鸿文[1] 邹丹 李歌[1] 

机构地区：[1]中国地质大学矿物材料国家专业实验室,北京100083 [2]吴青薪材技术有限公司,北京100083

出　　处：《岩石矿物学杂志》2011年第6期981-986,共6页Acta Petrologica et Mineralogica

基　　金：矿物材料国家专业实验室开放基金(04101)

摘　　要：实验研究了采用两步碱溶法从高铝粉煤灰中提取氢氧化铝的可行性。首先采用浓度为8 mol/L的NaOH溶液,在95℃的条件下溶出高铝粉煤灰中部分非晶态SiO2;所得脱硅粉煤灰再与适量CaO混合均匀,在260~280℃下以浓度18~20 mol/L的NaOH溶液溶出Al2O3,得到高苛性比的铝酸钠溶液;经降低苛性比、脱硅和碳酸化分解,制得氢氧化铝制品。化学成分分析结果表明,该氢氧化铝制品符合GB/T 4294-1997规定的一级标准。与其他从高铝粉煤灰中提取氧化铝的工艺相比,该方法避免了粉煤灰原料的高温烧结过程,生产能耗显著降低,加工过程的环境相容性良好。A new alkali dissolution method is used to extract aluminum hydroxide from high-alumina fly ash in this study.The first step alkali dissolution is to obtain desiliconized fly ash with relatively high Al2O3/SiO2 ratio.The amorphous silica in the fly ash is partly leached when the fly ash is leached with 8 mol/L sodium hydroxide solution at 95℃.The desiliconized fly ash is then used for the second step alkali dissolution as the material.The desiliconized fly ash mixed with CaO are leached with 18~20 mol/L sodium hydroxide solution at 260~280℃ and the dissolution efficiency of Al2O3 reaches 85%.Then reduced causticity ratio,deep desilication and carbonation decomposition are carried out on the basis of acquired sodium aluminate solution.The features of the prepared product of aluminum hydroxide are determined by XRD,SEM and chemical analysis.The results show that the aluminum hydroxide has fine crystal and slight particle aggregate sphere 70~80μm in diameter.The product can satisfy Class 1 of the China National Chemical Standard GB/T4294-1997.Compared with other technologies,this technology can avoid high temperature sintering procedure and realize low energy consumption,and the process is quite consistent with the environment protection idea.

关 键 词：高铝粉煤灰 碱溶法 氢氧化铝 

分 类 号：P579[天文地球—矿物学]