Factors affecting the preparation of aluminum hydroxide, Zhongtianli

Today, Zhongtianli will talk to you about the factors affecting the preparation of ultrafine aluminum hydroxide by salt hydrolysis method.

1. The influence of temperature.

Previous studies have shown that the effect of temperature on growth rate follows the Arrhenius relationship. As the temperature increases, the growth rate of crystal nuclei also increases, and the number of particles formed by the hydrolysis of alcohol and salt water to form aluminum hydroxide per unit time increases, resulting in a finer particle size. However, often due to the excessive and rapid number of generated grains, they collide and agglomerate with each other, increasing the likelihood of forming large grains. Meanwhile, due to the increase in hydrolysis temperature, the supersaturation of the solution decreases, the growth rate of crystals slows down, and the hydrolysis time prolongs, resulting in the growth of aluminum hydroxide particle size. On the contrary, if the temperature is too low, it will affect the growth rate of crystal nuclei, which is also significantly detrimental to the formation of finer particles. We know through experiments that when the temperature is controlled between 65~68 ℃, the endpoint pH of the alcoholization reaction is around 8, resulting in AI (OH); The purity is as high as 99.95%, and the particle size is less than 0.1gm. Especially, isopropanol has a better effect. At the same time, in order to recover organic solvents, temperature is strictly controlled during distillation. Therefore, we choose ethanol as the alcoholizing agent for 2 hours to further test the effect of temperature on particle size. Proper temperature is beneficial for the formation of fine particle sizes.

In this experiment, the factors that affect the particle size of aluminum hydroxide, in addition to the above, include the method of ammonia injection and its dosage, water quality parameters, etc., and detailed analysis and explanation will not be provided here. At the same time, analysis found that the impurities in the product Al (OH) were higher in SiOz and MgO, with SiO2 mainly brought in by anhydrous aluminum chloride and MgO mainly brought in by water. Therefore, improving the quality of raw materials is more advantageous for obtaining high-purity products.

Today, Zhongtianli will talk to you about the factors affecting the preparation of ultrafine aluminum hydroxide by salt hydrolysis method.

1. The influence of temperature.

Previous studies have shown that the effect of temperature on growth rate follows the Arrhenius relationship. As the temperature increases, the growth rate of crystal nuclei also increases, and the number of particles formed by the hydrolysis of alcohol and salt water to form aluminum hydroxide per unit time increases, resulting in a finer particle size. However, often due to the excessive and rapid number of generated grains, they collide and agglomerate with each other, increasing the likelihood of forming large grains. Meanwhile, due to the increase in hydrolysis temperature, the supersaturation of the solution decreases, the growth rate of crystals slows down, and the hydrolysis time prolongs, resulting in the growth of aluminum hydroxide particle size. On the contrary, if the temperature is too low, it will affect the growth rate of crystal nuclei, which is also significantly detrimental to the formation of finer particles. We know through experiments that when the temperature is controlled between 65~68 ℃, the endpoint pH of the alcoholization reaction is around 8, resulting in AI (OH); The purity is as high as 99.95%, and the particle size is less than 0.1gm. Especially, isopropanol has a better effect. At the same time, in order to recover organic solvents, temperature is strictly controlled during distillation. Therefore, we choose ethanol as the alcoholizing agent for 2 hours to further test the effect of temperature on particle size. Proper temperature is beneficial for the formation of fine particle sizes.

In this experiment, the factors that affect the particle size of aluminum hydroxide, in addition to the above, include the method of ammonia injection and its dosage, water quality parameters, etc., and detailed analysis and explanation will not be provided here. At the same time, analysis found that the impurities in the product Al (OH) were higher in SiOz and MgO, with SiO2 mainly brought in by anhydrous aluminum chloride and MgO mainly brought in by water. Therefore, improving the quality of raw materials is more advantageous for obtaining high-purity products.