Method for removing sodium in preparation of high-purity alumina

[0027] Take 1# aluminum hydroxide powder with an initial sodium content of 137ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 45g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH7.0~7.5, dry and dehydrate at 300°C; add 10g / L ammonium chloride to the washed and dried aluminum hydroxide at 30~50 Stir and wash in a constant temperature water bath at ℃ for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50 ℃, dry and dehydrate at 300 ℃ after washing, and transform it into a fluffy ultra-low sodium Aluminum hydroxide, the sodium content is 9ppm after testing.

[0029] Take 2# aluminum hydroxide powder with an initial sodium content of 296ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 35g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH 7.0-7.5, dry and dehydrate at 350°C; add 15g / L ammonium carbonate to the washed and dried aluminum hydroxide at 30-50°C Stir and wash in a constant temperature water bath for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50°C, dry and dehydrate at 500°C after washing, and transform it into a fluffy ultra-low sodium hydroxide Aluminum, tested sodium content is 8ppm.

[0031] Take 3# aluminum hydroxide powder with an initial sodium content of 327ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 35g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH 7.0-7.5, dry and dehydrate at 500°C; add 15g / L ammonium carbonate to the washed and dried aluminum hydroxide at 30-50°C Stir and wash in a constant temperature water bath for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50°C, dry and dehydrate at 500°C after washing, and transform it into a fluffy ultra-low sodium hydroxide Aluminum, tested sodium content is 7ppm.