Method for preparing silicon dioxide and aluminum oxide from coal ash
A technology of silicon dioxide and fly ash, applied in the directions of silicon dioxide, silicon oxide, alumina/aluminum hydroxide, etc., can solve the problem of unsatisfactory uniformity of solid raw materials, high metal ion content in sodium silicate liquid, equipment and Operators have high requirements to achieve the effect of high added value of products, reduced production costs, and simplified impurity removal procedures
Examples
Embodiment approach 1
[0028] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into the airtight reaction vessel, in which 500 g of fly ash, the molar ratio of sodium carbonate and calcium oxide is 3, the mass ratio of fly ash and calcium oxide is 2, and the liquid The solid ratio is 4, after 30 minutes of alkali dissolution at a temperature of 180°C and a pressure of 0.9 MPa, the sodium silicate solution, desilication fly ash and calcium carbonate solid mixture are separated by filtration, the solid mixture is washed, and the desilication ash is dried;
[0029] Sodium silicate solution enters CO 2 Carbon is used to prepare silicon dioxide, a solid mixture of partially desiliconized fly ash and calcium carbonate is mixed with cement and foaming agent with water to prepare foamed concrete.
[0030] The partially desiliconized fly ash and calcium carbonate solid mixture are prepared by soda lime sintering method to prepare alumina, and the waste residue after preparing alum...
Embodiment approach 2
[0032] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into the airtight reaction vessel, in which 500 g of fly ash, the molar ratio of sodium carbonate and calcium oxide is 3, the mass ratio of fly ash and calcium oxide is 2, and the liquid The solid ratio is 4, at 240°C and 1.2MPa pressure, after 30 minutes of alkali dissolution, filtered to separate the sodium silicate solution, desilication fly ash and calcium carbonate solid mixture, wash the solid mixture, and dry the desilication ash;
[0033] Sodium silicate solution enters CO 2 Carbon, silica is prepared, the solid mixture of desiliconized fly ash and calcium carbonate is prepared by soda lime sintering method to prepare alumina, and the waste residue after preparing alumina by soda lime sintering method is used to prepare foamed concrete blocks.
Embodiment approach 3
[0035] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into a closed reaction vessel, where fly ash is 500g, the molar ratio of sodium carbonate and calcium oxide is 1, and the mass ratio of fly ash to calcium oxide is 4. The solid ratio is 6. After being dissolved in alkali for 50 minutes at 300°C and 7.2MPa pressure, the mixture of sodium silicate solution, desilication fly ash and calcium carbonate solid mixture is filtered and separated, the solid mixture is washed, and the desilication ash is dried;
[0036] Sodium silicate solution enters CO 2 Carbon content, silica is prepared, the solid mixture of desiliconized fly ash and calcium carbonate is prepared by the soda lime sintering method to prepare alumina, and the waste slag after preparing the alumina by the soda lime sintering method is beaten and used for the purification of coal-fired boiler tail gas.
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