Method of removing ammonia from fly ash and fly ash composition produced thereby
View Patent ↗A method of treating fly ash and fly ash treated thereby, the method involving contacting ammonia-laden fly ash with an organic base-containing treatment composition, where the organic base causes the ammonia within the fly ash to evolve from the fly ash. The treatment composition preferably includes an effective amount of one or more amines. The treatment compound may be applied to the fly ash in any manner effective to disperse the treatment compound among the fly ash.
1. A process for the production of cementitious material comprising the steps of
supplying an ammonia-laden fly ash;
supplying a treatment composition comprising one or more organic bases;
contacting the ammonia-laden fly ash with the treatment composition to produce a treated fly ash having an ammonia content of less than about 150 ppm per total weight of the treated fly ash; and
mixing the treated fly ash with a hydraulic cement.
2. The process of claim 1 , further comprising mixture of the formed cementitious material with an aggregate material to form concrete.
3. The process of claim 1 , further comprising the step of agitating the fly ash and the treatment composition prior to mixing the treated fly ash and the hydraulic cement.
4. The process of claim 1 , further comprising the step of heating the fly ash and the treatment composition prior to mixing the treated fly ash and the hydraulic cement.
5. The process of claim 1 , wherein the treatment composition is a non-aqueous composition.
6. The process of claim 1 , wherein the one or more organic bases have a pK b value of less than 4.75.
7. The process of claim 1 , wherein the treatment composition comprises one or more amines.
8. The process of claim 7 , wherein the one or more amines are selected from the group consisting of amines with a pK b value of less than 4.75.
9. The process of claim 7 , wherein the one or more amines include one or more amines selected from the group consisting of cycloamines, diamines, polyamines, and compounds represented by formula (I)
where R 1 and R 2 are independently selected from hydrogen, C 1 -C 8 alkyl, C 1 -C 4 hydroxyalkyl, aryl, and hydroxyaryl, wherein the alkyl, hydroxyalkyl, aryl and hydroxyaryl groups may be substituted or unsubstituted and branched or unbranched, and R 3 is selected from C 1 -C 18 alkyl, C 1 -C 4 hydroxyalkyl (including alkoxylated hydroxyalkyl), aryl, hydroxyaryl, and C 2 -C 4 alkenyl, wherein the alkyl, hydroxyaryl, aryl, hydroxyaryl and alkenyl groups may be substituted or unsubstituted and branched or unbranched.
10. The process of claim 9 , wherein the one or more amines includes one or more amines selected from the group consisting of compounds represented by formula (I)
wherein R 1 is selected from hydrogen and C 1 -C 8 alkyl wherein the alkyl groups may be substituted or unsubstituted and branched or unbranched; R 2 is selected from hydrogen, C 1 -C 8 alkyl and C 1 -C 4 hydroxyalkyl, wherein the alkyl and hydroxyalkyl groups may be substituted or unsubstituted and branched or unbranched, and R 3 is selected from C 1 -C 18 alkyl, C 1 -C 4 hydroxyalkyl (which may be alkoxylated with 1-3 oxyalkylene groups), aryl, and C 2 -C 4 alkenyl, wherein the alkyl, hydroxylalkyl, aryl and alkenyl groups may be substituted or unsubstituted and branched or unbranched.
11. The process of claim 9 , wherein the one or more amines are selected from the group consisting of monoethanol amine, diethanol amine, triethanol amine, 1-amino-2-propanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 2-(methylamino)-ethanol, 2-(2-aminoethyoxy)ethanol, ethylenediamine, and diethyenetriaminee.
12. The process of claim 9 , wherein the one or more amines selected from the group consisting of cycloamines, diamines, polyamines, and amines represented by formula (I) includes one or more amines with a pK b value of less than 4.75.
13. The process of claim 9 , wherein the one or more amines selected from the group consisting of cycloamines, diamines, polyamines, and amines represented by formula (I) includes two or more amines with a pK b value of less than 4.75.
14. The process of claim 9 , wherein the one or more amines selected from the group consisting of cycloamines, diamines, polyamines, and amines represented by formula (I) includes one or more amines with a pK b value of less than 4.75 and one or more amines with a pK b value of more than 4.75.
15. The process of claim 1 , wherein the water content in the treatment composition produces a treated fly ash having less than 1.5 wt % water, based on the total wt % of the fly ash.
16. The process of claim 1 , wherein the treatment composition is supplied as a liquid spray.
17. The process of claim 1 , wherein the treatment composition is supplied as a vapor.
18. The process of claim 1 , wherein the step of contacting the ammonia-laden fly ash with the treatment composition comprises the step of determining the amount of the treatment composition to be applied to the ammonia-laden fly ash based on the flow rate of the fly ash.
19. The process of claim 1 , wherein the step of contacting the ammonia-laden fly ash with the treatment composition comprises the step of pressurizing the treatment composition prior to contacting the treatment composition with the fly ash.
20. The process of claim 1 , further comprising the step of contacting the fly ash with a treating fluid comprising an agent selected from the group consisting of sacrificial agents, surfactants, dispersants, chemical activators, coating compositions, and combinations thereof.
21. The process of claim 1 , wherein the treatment composition further comprises at least one alkaline salt.
22. The process of claim 21 , wherein the treatment composition further comprises at least one alkaline salt selected from the group consisting of sodium carbonate, sodium aluminate, and sodium silicate.