Method for Preparing a Soda-Lime-Silica Glass Basic Formulation and a Method for Extracting Aluminum from Coal Ash for Co-Production of Glass

• US 20150321946A1
• Filed: 11/27/2012
• Published: 11/12/2015
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: China Energy Investment Corporation Limited
• Original Assignee: National Institute of Clean-and-Low-Carbon Energy, Shenhua Group Corporation Limited
• Inventors: Sun, Qi, Zhao, Lijun, Wang, Baodong, Liu, Xiaoting
• Granted Patent: US 9,517,965 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C03C 1/002 Use of waste materials, e.g. slags
• CPC Class Codes: C03C 1/006 to produce glass through wet route
• CPC Class Codes: C03C 3/062 with less than 40% silica by weight
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum

Abstract

The present invention discloses a method for preparing a soda-lime-silica glass basic formulation and a method for producing soda-lime-silica glass, comprising the steps of: pre-desiliconizing silicon-containing powdery industrial waste with a sodium hydroxide solution; introducing carbon dioxide for carbonation decomposition, and filtering to obtain a silicic acid precipitate and a sodium carbonate solution; drying the silicic acid precipitate to obtain silicon dioxide; adding lime milk into the filtered sodium carbonate for causticization, and filtering to obtain a sodium hydroxide solution and a calcium carbonate precipitate; drying the calcium carbonate precipitate; using said silicon dioxide and part of the calcium carbonate and adding sodium oxide. The present invention further discloses a method for extracting aluminum from coal ash for co-production of soda lime glass, which uses silicon dioxide obtained from alkali dissolution and desiliconization of coal ash and calcium carbonate generated from causticization as main raw materials. The method for extracting aluminum from coal ash for co-production of soda lime glass according to the present invention integrates and optimizes a process of extracting aluminum from the coal ash, has a high material and energy utilization rate, good quality of co-product glass, and high added value, and can greatly improve economical efficiency of aluminum extraction of coal ash.

Claims

1. A method for preparing a soda-lime-silica glass basic formulation, comprising the steps of:

a1) pre-desiliconizing silicon-containing powdery industrial waste with a sodium hydroxide solution, and separating, to obtain a pre-desiliconization mother liquor and residues;

a2) introducing carbon dioxide to the pre-desiliconization mother liquor for carbonation decomposition, and separating, to obtain a silicic acid precipitate and a sodium carbonate solution;

a3) drying the silicic acid precipitate to obtain silicon dioxide;

a4) adding lime milk into the sodium carbonate solution for causticization, and separating, to obtain a calcium carbonate precipitate and a sodium hydroxide solution;

a5) drying the calcium carbonate precipitate; and

a6) according to the requirements on the amounts of respective components in the soda-lime-silica glass, using the silicon dioxide prepared in step a3) and part of the dried calcium carbonate from step a5) and adding sodium oxide thereto, to obtain a soda-lime-silica glass basic formulation.

2. The method according to claim 1, wherein said silicon-containing powdery industrial waste is selected from the group consisting of one or more of pulverized or unpulverized coal ash, stove ash, clay, kaolin, slag and red mud.

3. The method according to claim 1 or 2, which further comprises at least one of the following steps:

a1-1) subjecting the silicon-containing powdery industrial waste to magnetic separation for removing iron prior to the step a1) of pre-desiliconization;

a4-1) recovering the sodium hydroxide solution obtained in step a4), to allow its use in the pre-desiliconization of the silicon-containing powdery industrial waste in step a1);

a5-1) calcining part of the dried calcium carbonate precipitate from step a5) and preparing lime milk, to allow the addition of the lime milk to the filtered sodium carbonate for causticization in step a4); and

a5-2) recovering carbon dioxide obtained by calcining the calcium carbonate precipitate, to allow its use in the carbonation decomposition in step a2).

4. The method according to any one of claims 1 to 3, wherein said silicon-containing powdery industrial waste is coal ash.

5. The method according to claim 4, wherein in step a1), the mass concentration of sodium hydroxide in the solution is 10% to 50%, the mass ratio of coal ash to sodium hydroxide is 100:

15 to 150, the reaction temperature is between 60°

C. and 150°

C., and the reaction time lasts for 0.5 h to 10 h.

6. The method according to claim 5, wherein in step a1), the mass concentration of sodium hydroxide in the solution is 15% to 35%, the mass ratio of coal ash to sodium hydroxide is 100:

30 to 90, the reaction temperature is 70°

C. to 130°

C., and the reaction time lasts for 1 h to 4 h.

7. The method according to claim 5 or 6, wherein in step a1), the mass ratio of SiO₂ to Al₂O₃ in the resulting pre-desiliconized mother liquor is greater than 6.

8. The method according to any one of claims 1 to 7, wherein in step a6), silicon dioxide and calcium carbonate obtained respectively in steps a3) and a5) comprise 70% to 95% by weight of the glass basic formulation.

9. A method for producing soda-lime-silica glass by using the soda-lime-silica glass basic formulation of any one of claims 1 to 8, comprising:

a7) adding potassium oxide and/or aluminum oxide and/or magnesium oxide, and/or auxiliaries according to the requirements on the amounts of respective components of the soda-lime-silica glass; and

a8) performing glass melting, forming, and annealing.

10. The method according to claim 9, which further comprises a step of reprocessing to obtain a glass product.

11. The method according to claim 9, wherein, said forming process is a pressing process, a blowing process, a drawing process, a rolling process, casting forming or float forming.

23. A soda lime glass article, prepared according to the method of any one of claims 1 to 22.

12. A method for extracting aluminum from coal ash for co-production of glass, comprising the steps of:

b1) pre-desiliconizing coal ash with a sodium hydroxide solution, and separating, to obtain a pre-desiliconization mother liquor and residues;

b2) introducing carbon dioxide to the pre-desiliconization mother liquor for carbonation decomposition, and separating, to obtain a silicic acid precipitate and a sodium carbonate solution;

b3) drying the silicic acid precipitate to obtain silicon dioxide;

b4) adding lime milk into the sodium carbonate solution for causticization, and separating, to obtain a calcium carbonate precipitate and a sodium hydroxide solution;

b5) drying the calcium carbonate precipitate;

b6) according to the requirements on the amounts of respective components in the soda-lime-silica glass, using the silicon dioxide prepared in step b3) and part of the dried calcium carbonate from step b5) and adding sodium oxide thereto, to obtain a soda-lime-silica glass basic formulation; and

b7) performing aluminum extraction by using the resulting residues obtained in step b1).

13. The method according to claim 12, which further comprises:

b8) adding potassium oxide and/or aluminum oxide and/or magnesium oxide, and/or auxiliaries according to the requirements on the amounts of respective components of the soda-lime-silica glass; and

b9) performing glass melting, forming, annealing, and reprocessing to obtain a glass product.

14. The method according to claim 12, which further comprises at least one of the following steps:

b1-1) subjecting the silicon-containing powdery industrial waste to magnetic separation for removing iron prior to the step b1) of pre-desiliconization;

b4-1) recovering the sodium hydroxide solution obtained in step b4), to allow its use in the pre-desiliconization of the silicon-containing powdery industrial waste in step b1);

b5-1) calcining part of the dried calcium carbonate precipitate from step b5) and preparing lime milk, to allow the addition of the lime milk to the filtered sodium carbonate for causticization in step a4); and

b5-2) recovering carbon dioxide obtained by calcining the calcium carbonate precipitate, to allow its use in the carbonation decomposition in step b2).

15. The method according to any one of claims 12 to 14, wherein in step b1), the mass concentration of sodium hydroxide in the solution is 10% to 50%, the mass ratio of coal ash to sodium hydroxide is 100:

15 to 150, the reaction temperature is between 60°

C. and 150°

C., and the reaction time lasts for 0.5 h to 10 h.

16. The method according to claim 15, wherein in step b1), the mass concentration of sodium hydroxide in the solution is 15% to 35%, the mass ratio of coal ash to sodium hydroxide is 100:

30 to 90, the reaction temperature is between 70°

C. and 130°

C., and the reaction time lasts for 1 h to 4 h.

17. The method according to claim 15 or 16, wherein in step b1), the mass ratio of SiO₂ to Al₂O₃ in the resulting pre-desiliconized mother liquor is greater than 6.

18. The method according to any one of claims 12 to 17, wherein in step b6), silicon dioxide and calcium carbonate obtained respectively in steps b3) and b5) comprise 70% to 95% by weight of the glass basic formulation.

19. The method according to claim 13, wherein said forming process is a pressing process, a blowing process, a drawing process, a rolling process, casting forming or float forming.

20. The method according to any one of claims 12 to 17, which further comprises:

b5-3) mixing at least part of the dried calcium carbonate precipitate from step b5) directly with the residues obtained from step b1), followed by soda lime sintering to prepare clinker for aluminum extraction; and

/or

b5-4) calcining part of the dried calcium carbonate precipitate from step b5) at first to obtain lime, which is then mixed with the residues obtained from step b1), followed by soda lime sintering to prepare clinker for aluminum extraction.

21. The method according to claim 20, wherein the mixing of the materials during the process of soda lime sintering ensures a molar ratio of [CaO]/([SiO₂]+x[TiO₂]) between 0.8 and 2.2, wherein 0.5≦

x≦

1.0; and

a molar ratio of [Na₂O]/([Al₂O₃]+[Fe₂O₃]+y[SiO₂]) between 0.8 and 1.2, wherein 0≦

y≦

1.0.

22. The method according to claim 20, wherein the soda lime sintering to prepare clinker is carried out by calcination at a temperature between 800 and 1500°

C., preferably between 1000 and 1300°

C.