Effect of calcination parameters of alumina hydrate on the properties of alumina

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">In the present investigation, the variation of properties of alumina hydrate and alumina during calcination with respect to different parameters like temperature, retention time, grain size and soda content to evaluate the change of BET surface area have been studied. The effect of mineralisers like AIF₃ and NH₄F, for transformation of alpha phase of alumina has also been studied on a laboratory scale. Coversion to about 96% of alpha alumina was achieved by using 1% of mineraliser at 1100<span style="font-size:11.0pt; line-height:115%;font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;="" mso-fareast-font-family:"times="" new="" roman";mso-fareast-theme-font:minor-fareast;="" mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:="" en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">ᵒ<span style="font-size:11.0pt;line-height:115%;font-family:" calibri","sans-serif";="" mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"times="" new="" roman";="" mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:minor-latin;="" mso-bidi-font-family:"times="" roman";mso-bidi-theme-font:minor-bidi;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"=""> C. While the BET surface area reduced with temperature and finner size of alumina hydrate, the alpha formation showed an increasing trend. The change of properties like density, porosity, humidity and compressibility with respect to temperature has also been reported.</span></span></span>