Detailed explanation of the process of calcining, grinding and sorting aluminum ash

Calcination process

Purpose: Calcination process is a key link in the aluminum ash treatment process. Through high-temperature treatment, harmful substances in aluminum ash, such as aluminum nitride and fluoride, can be decomposed. These substances will undergo chemical reactions at high temperatures to produce harmless or low-toxic substances. At the same time, the calcination process can also extract valuable components in aluminum ash, such as alumina, laying the foundation for the subsequent recycling of aluminum resources.

Equipment: The calcination process mainly uses a rotary kiln as the core equipment. The internal temperature of the rotary kiln is controlled between 1100℃ and 1300℃ to ensure that the aluminum ash and limestone mixture can fully react. Aluminum ash and limestone are mixed in a certain proportion and sent to the rotary kiln for high-temperature calcination.

Chemical reaction: During the calcination process, aluminum nitride reacts with oxygen to generate aluminum oxide and nitrogen to achieve the purpose of denitrification; fluoride reacts with calcium chloride to generate calcium fluoride precipitation and sodium chloride to achieve the effect of fluorine fixation. These chemical reactions not only reduce the emission of harmful substances, but also generate materials such as calcium aluminate that can be used in building materials, refractory materials and other fields.

‌Grinding process‌

‌Equipment‌: The grinding process uses a ball mill as the main equipment. The ball mill separates the symbiosis of aluminum ash and aluminum particles through mechanical grinding, and uses the plasticity of aluminum to increase the particle size, providing favorable conditions for subsequent sorting processes.

‌Function‌: The grinding process significantly improves the recovery rate of aluminum particles. After grinding, the fine aluminum particles that were originally difficult to separate become easier to screen out, and the recovery rate can be increased by 5%~30%. At the same time, grinding can also optimize the subsequent screening efficiency, reduce the loss of fine aluminum particles, and improve the overall resource utilization rate.

‌Screening process

‌Equipment‌: The sorting process mainly includes two links: coarse screening and fine screening. Coarse screening uses a linear vibrating screen or a drum screen to separate large and medium particles of aluminum; fine screening uses a sieve or a drum screen for secondary processing to screen fine-grained aluminum. In addition, in order to capture the dust generated during the screening process and extend the life of the equipment, a cyclone dust collector and a pulse bag dust collector are used in combination.

‌Process‌: After the aluminum ash is ground, it enters the sorting process. First, large and medium-sized aluminum particles are separated through coarse screening; then fine-grained aluminum is further screened through fine screening; finally, dust is captured and the air is purified through dust removal equipment. The entire sorting process achieves efficient treatment and resource recycling of aluminum ash.