Agglomeration of ultra-fine coal particles
A method of preparing agglomerates of ultra-fine coal particles includes mixing a film forming agglomeration aid (FFAA) with a quantity of ultra-fine coal particles to form ultra-fine coal particles coated with the FFAA. The FFAA has a lower surface energy relative to a surface of the ultra-fine coal particles. The FFAA is mixed with the ultra-fine coal particles in an amount less than 3% by weight of the ultra-fine coal particles on a dry basis. Agglomerates of the ultra-fine coal particles coated with the film forming agglomeration aid are formed using vibration, pelleting, and/or briquetting. The agglomerates have a size of at least 2 mm. The ultra-fine coal particles have a particle size less than 100 μm. The agglomerate has a tumbler test friability less than 3%. The drop shatter friability is also less than 3%.
1. An agglomerate of ultra-fine coal particles consisting of ultra-fine coal particles having a particle size less than 100 μm hound together by a film forming agglomeration aid which coats a surface of the ultra-fine coal particles, wherein the agglomerate has size dimensions greater than 2 mm, wherein the film forming agglomeration aid is present in an amount less than 3% by weight of the total dry mass of the agglomerate.
2. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the agglomerate has a tumbler test friability less than 3%.
3. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the agglomerate has a drop shatter friability less than 3%.
4. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the ultra-fine coal particles have a particle size less than 50 μm.
5. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the ultra-fine coal particles have a particle size less than 25 μm.
6. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid is present in an amount less than 2% by weight of the ultra-fine coal particles on a dry basis.
7. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid is present in an amount less than 1% by weight of the ultra-fine coal particles on a dry basis.
8. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the agglomerate absorbs less than 8% by weight water upon exposure to water for 24 hours.
9. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid is a carbon-based polymer.
10. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the agglomerate possesses one or more coal properties equivalent to coal from which the ultra-fine coal particles originate, wherein the coal properties are selected from volatile matter, ash chemistry, and rank.
11. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the ultra-fine coal particles comprise a blend of two or more sources of ultra-fine coal particles.
12. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid has a lower surface energy relative to the surface of the ultra-fine coal particles which is coated by the film forming agglomeration aid.
13. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid is soluble in aqueous solution.
14. The agglomerate of ultra-fine coal particles according to claim 1 , wherein the film forming agglomeration aid is an aqueous colloidal suspension.
15. An agglomerate of ultra-fine coal particles consisting of ultra-fine coal particles having a particle size less than 100 μm bound together by a film forming agglomeration aid which coats a surface of the ultra-fine coal particles and a water repellant surface coating, wherein the agglomerate has size dimensions greater than 2 mm, wherein the film forming agglomeration aid is present in an amount less than 3% by weight of the total dry mass of the agglomerate, and wherein the water repellant surface coating is present in an amount less than 0.5% by weight of the agglomerate on a dry basis.
16. The agglomerate of ultra-fine coal particles according to claim 15 , wherein the agglomerate absorbs less than 4% by weight water upon exposure to water for two weeks.