Method for synchronously preparing sodium aluminate through aluminum ash soda sintering denitrification

[0024] Example 1:

[0025] Take the aluminum ash (aluminum content 58.6%, nitrogen content 8.3%) of an aluminum metallurgical plant as raw materials, first mix the aluminum ash and the mixed sodium salt according to the aluminum-sodium element ratio of 1:1.1, and the mixed sodium salt ratio is sodium carbonate and carbonic acid The mass ratio of sodium hydrogen and sodium peroxide is 85:17:8. The raw materials are mixed and pressed into agglomerates with a diameter of 15mm; after the agglomerates are fully dried, they are placed in an air atmosphere for a period of roasting, and the roasting temperature is 500℃. The roasting time is 120min, the roasting atmosphere is air; the second-stage roasting temperature is 700℃, the roasting time is 120min, and the roasting atmosphere is O 2 /(O 2 +N 2 )=40%; after calcination, the cooled agglomerates are crushed, immersed in an alkaline solution, and solid-liquid separated to obtain a sodium aluminate solution. In the whole process, the aluminum recovery rate is 92.3%, the nitrogen removal rate is 98.3%, and the ratio of nitrogen element converted into nitrogen is 99.3%.

[0026] Example 2:

[0027] Take the aluminum ash (aluminum content 58.6%, nitrogen content 8.3%) of an aluminum metallurgical plant as raw materials, first mix the aluminum ash and the mixed sodium salt according to the aluminum-sodium element ratio of 1:1.3, and the mixed sodium salt ratio is sodium carbonate and carbonic acid The mass ratio of sodium hydrogen and sodium peroxide is 70:25:5. The raw materials are mixed and pressed into agglomerates with a diameter of 15mm; after the agglomerates are fully dried, they are placed in an air atmosphere for a period of roasting, and the roasting temperature is 300℃. The roasting time is 180min, the roasting atmosphere is air; the second-stage roasting temperature is 875℃, the roasting time is 150min, and the roasting atmosphere is O 2 /(O 2 +N 2 )=65%; after calcination, the cooled agglomerates are crushed, immersed in an alkaline solution, and solid-liquid separated to obtain a sodium aluminate solution. In the whole process, the aluminum recovery rate was 94.2%, the nitrogen removal rate was 99.0%, and the ratio of nitrogen element converted into nitrogen was 98.8%.

[0028] Example 3:

[0029] Take the aluminum ash (aluminum content 58.6% and nitrogen content 8.3%) of an aluminum metallurgical plant as raw materials. First, the aluminum ash and the mixed sodium salt are mixed according to the aluminum-sodium element ratio of 1:1.2, and the mixed sodium salt ratio is sodium carbonate and carbonic acid The mass ratio of sodium hydrogen and sodium peroxide is 70:17:13. The raw materials are mixed and pressed into agglomerates with a diameter of 15mm; after the agglomerates are fully dried, they are placed in an air atmosphere for a period of roasting at a roasting temperature of 500°C. The roasting time is 150min, the roasting atmosphere is air; the second-stage roasting temperature is 850℃, the roasting time is 180min, and the roasting atmosphere is O 2 /(O 2 +N 2 )=55%; after the roasting, the cooled agglomerates are crushed, immersed in an alkaline solution, and solid-liquid separated to obtain a sodium aluminate solution. In the whole process, the aluminum recovery rate was 95.1%, the nitrogen removal rate was 98.8%, and the ratio of nitrogen element converted to nitrogen was 99.2%.