Chemical purification method for preparing ultralow ash content coal from clean coal

[0041] This example discloses a chemical purification method for producing ultra-low ash coal from clean coal, see figure 1 , is a process flow diagram of the present invention. The clean coal: 5% ash.

[0042] Include the following steps:

[0043] S1. Oxygen barrier activated roasting: In an oxygen-free environment, the temperature is 950 ° C, and the coal with 5% ash content is roasted for 40 minutes. The aluminosilicate minerals in the ash are activated to form amorphous SiO 2 and a'-Al 2 o 3 ;Carbon burning rate of 1.5% in the roasting process;

[0044] S2. Separation of silicon by alkali dissolution at low temperature: adding Na to the activated roasting product obtained in S1 2 Ok concentration is 100g / L caustic alkali solution, temperature 100 ℃, reaction 3h, filter to obtain aluminum-containing coal and silicon-containing filtrate;

[0045] S3. High-temperature alkali-dissolution separation of aluminum: the aluminum-containing coal obtained in S2 is added to the s

[0048] This example discloses a chemical purification method for producing ultra-low ash coal from clean coal, see figure 1 , is a process flow diagram of the present invention. The clean coal: 3% ash.

[0049] Include the following steps:

[0050] S1. Oxygen barrier activated roasting: In an oxygen-free environment, the temperature is 1000 ° C, and the coal with ash content of 3% is roasted for 30 minutes. The aluminosilicate minerals in the ash are activated to form amorphous SiO 2 and a'-Al 2 o 3 ;Carbon burning loss aluminum 1.8% in the roasting process;

[0051] S2. Separation of silicon by alkali dissolution at low temperature: adding Na to the activated roasting product obtained in S1 2 Ok concentration is 130g / L caustic alkali solution, temperature 95 ℃, react for 2h, filter to obtain aluminum-containing coal and silicon-containing filtrate;

[0052] S3. High-temperature alkali-dissolution separation of aluminum: the aluminum-containing coal obtained in S2 is adde

[0055] This example discloses a chemical purification method for producing ultra-low ash coal from clean coal, see figure 1 , is a process flow diagram of the present invention. The clean coal: ash content 3.5%.

[0056] Include the following steps:

[0057] S1. Oxygen barrier activated roasting: In an oxygen-free environment, the temperature is 1050 ° C, and the coal with ash content of 3.5% is roasted for 20 minutes. The aluminosilicate minerals in the ash are activated to form amorphous SiO 2 and a'-Al 2 o 3 2.2% of aluminum is lost by carbon burning in the roasting process;

[0058] S2. Separation of silicon by alkali dissolution at low temperature: adding Na to the activated roasting product obtained in S1 2 Ok concentration is 150g / L caustic alkali solution, temperature 110 ℃, react for 1h, filter to obtain aluminum-containing coal and silicon-containing filtrate;

[0059] S3. High-temperature alkali-dissolution separation of aluminum: the aluminum-containing coal o