GRINDING ADDITIVE FOR CARBONACEOUS SOLID

Abstract

The invention relates to a method for grinding a carbonaceous solid, wherein a grinding additive is added before or during grinding, and the grinding additive, based on the dry mass, comprises 6% to 80% by weight of caprolactam and 1.5% to 30% by weight of aminocaproic acid, where, based in each case on the dry mass, 0.002% to 2% by weight of the grinding additive is used, based on the total amount of carbonaceous solid. Further claimed are a grinding additive and the use of a grinding additive for reducing the energy employed for a given grinding outcome and also for reducing the agglomeration tendency of the resultant product.

Claims

1. A method for grinding a carbonaceous solid, wherein a grinding additive is added before or during grinding, characterized in that the grinding additive, based on the dry mass, comprises 6% to 80% by weight of caprolactam and 1.5% to 30% by weight of aminocaproic acid, where, based in each case on the dry mass, 0.002% to 2% by weight of the grinding additive is used, based on the total amount of carbonaceous solid.

2. The method according to claim 1, characterized in that the grinding additive comprises at least one further grinding additive selected from the group of polycarboxylate ethers, lignosulphonate, melamine-formaldehydesulphonate, naphthalene-formaldehydesulphonate, mono-glycols, di-glycols, tri-glycols, polyglycols, polyalcohols, alkanolamine, amino acids, sugars, molasses, organic salts, inorganic salts, monocarboxylic acids with 1 to 4 carbon atoms, and surfactants.

3. The method according to claim 1, characterized in that the carbonaceous solid is at least one selected from the group of coal, coke, and petcoke.

4. The method according to claim 1, characterized in that, based in each case on the dry mass, 0.01% to 0.5% by weight of the grinding additive is used, based on the total amount of carbonaceous solid.

5. The method according to claim 1, characterized in that the grinding additive is applied as an aqueous suspension.

6. The method according to claim 1, characterized in that the grinding additive is applied before grinding.

7. The method according to claim 1, characterized in that the grinding additive, based on the dry mass, comprises 1% to 20% by weight of alkali metal hydroxide.

8. The method according to claim 1, characterized in that the grinding additive comprises caprolactam oligomers.

9. The method according to claim 1, characterized in that grinding is carried out in a vertical roller mill.

10. A method comprising adding of a mixture comprising, based on the dry mass, 6% to 80% by weight of caprolactam and 1.5% to 30% by weight of aminocaproic acid as grinding additive for a carbonaceous solid, where, based in each case on the dry mass, 0.002% to 2% by weight of the grinding additive is used, based on the carbonaceous solid, for reducing the energy employed for a given grinding outcome and also for reducing the agglomeration tendency of the resultant product.

11. A composition comprising, based in each case on the dry mass, a carbonaceous solid and based on the total amount of the carbonaceous solid, 0.002% to 2% by weight of a mixture comprising, 6% to 80% by weight of caprolactam and 1.5% to 30% by weight of aminocaproic acid.

12. The composition according to claim 11, characterized in that the composition comprises more than 80% by weight of a carbonaceous solid.

13. The composition according to claim 11, characterized in that the mixture is a grinding additive comprising at least one further grinding additive selected from the group of polycarboxylate ethers, lignosulphonate, melamine-formaldehydesulphonate, naphthalene-formaldehydesulphonate, mono-glycols, di-glycols, tri-glycols, polyglycols, polyalcohols, alkanolamine, amino acids, sugars, molasses, organic salts, inorganic salts, monocarboxylic acids with 1 to 4 carbon atoms, and surfactants.

14. The composition according to claim 11, characterized in that the carbonaceous solid is at least one selected from the group of coal, coke, and petcoke.

15. The composition according to claim 11, characterized in that, based in each case on the dry mass, 0.01% to 0.5% by weight of the mixture is present, based on the total amount of carbonaceous solid.

16. The composition according to claim 11, characterized in that the mixture, based on the dry mass, comprises 1% to 20% by weight of alkali metal hydroxide.

17. The composition according to claim 11, characterized in that the mixture comprises caprolactam oligomers.

Description

EXAMPLES

[0032] General Test Procedure

[0033] The grinding tests are carried out in a planetary laboratory ball mill (PM 100, Retsch GmbH). A total weight of 30 g petcoke (table 1) or coal (table 2) is weighed out beforehand on a precision balance and pre-grinded 3 minutes for uniformity without grinding additive in the mill. Based on the weight of petcoke or coal the amount of grinding additive according to table 1 or table 2 is added. Grinding is then carried out for 12 minutes at ambient temperature (25 C.). The resultant petcoke or coal is sieved through a 1 mm sieve in order to remove the grinding beads.

TABLE-US-00001 TABLE 1 Petcoke grinding test Grinding Additive A D none water Concentration of 50% by 50% by 100% Grinding Additive weight weight in water in water Dosage ppm 900 830 1060 D50 value 14.75 15.02 15.29 15.61

TABLE-US-00002 TABLE 2 Coal grinding test Grinding Additive A B C Concentration of 40% by 45% by 50% by Grinding Additive weight weight weight in water in water in water Dosage 1300 800 830 D50 value 14.47 15.57 15.42

[0034] The particle size (D50 value) is determined as the average of two measurements by laser particle granulometry (Mastersizer 2000, Malvern Instruments Ltd).

[0035] A: The inventive grinding additive is a product from preparation of caprolactam, containing 30.2% by weight caprolactam monomer, 14.1% by weight oligomers of caprolactam, 7% by weight aminocaproic acid, 26.6% by weight water, 5.2% by weight NaOH and 11.9% by weight other organic constituents.

[0036] B: Polycarboxylate ether (Sokalan CP 45, BASF SE)

[0037] C: Raw glycerol 80% from bio-diesel production process

[0038] D: Diethylene glycol 99%, tech grade

[0039] All dosages were adapted to get approximately the same active content of the main ingredient.

[0040] Coal or petcoke after grinding with inventive grinding additive A show the best value of global fineness and particle size distribution compared with other typical grinding additives used for grinding carbonaceous solids.