Synthesis of high-purity Na-A and Na-X zeolite from coal fly ash

Figures & data

1. Chemical composition of original CFA samples analyzed by XRF

Chemical Composition	%wt
SiO2	37.51 ± 5.63
Al2O3	18.07 ± 2.39
Fe2O3	15.28 ± 4.53
CaO	14.72 ± 3.83
K2O	02.91 ± 0.54
Na2O	02.79 ± 1.68
TiO2	02.64 ± 0.49
MgO	02.43 ± 0.60
Other (i.e., SO3, P2O5, SrO, ZrO2, NiO, Y2O3, and Rb2O)	03.21 ± 2.27

1. Process flow diagram for zeolite synthesized from CFA. W = sample loss from mixing step (g); × = sample loss from fusion step (g); Y = sample loss from grinding step (g); Z = sample loss from washing step (g).

2. Schematic diagram of the water adsorption experiment setup.

3. Chemical compositions of zeolite products, synthesized from CFA treated with various acids (a), various L/S ratios (b), and reused acid (c).

2. Properties of zeolite products synthesized from CFA with various conditions

	Conditions				Results
Parameter Studied	Raw CFA	Acid Types	L/S (mL/g)	Si/Al (molar ratio)	XRD Analysis	Yield(%)	Surface Area (m^2/g)	Pore Size(Å)	Pore Volume (cc/g)	Highest Ethanol Concentration (%wt)	A (g/g)	asp (g/g)
Effect of acid types	CFA8	Nontreated	25	1.73	SAS	55	058	3.42	0.25	96.6	4.02 × 10^−3	7.32 × 10^−3
	CFA8	H2SO4	25	1.73	SAS	33	226	4.17	0.29	97.7	4.22 × 10^−3	1.28 × 10^−2
	CFA8	HNO3	25	1.73	SAS	34	139	4.30	0.12	98.1	5.01 × 10^−3	1.47 × 10^−2
	CFA8	HCl	25	1.73	SAS	33	261	4.34	0.80	98.3	5.08 × 10^−3	1.54 × 10^−2
Effect of L/S ratio	CFA8	HCl	05	1.73	SAS	32	035	3.61	0.16	97.2	3.39 × 10^−3	1.06 × 10^−2
	CFA8	HCl	10	1.73	SAS	31	072	3.62	0.17	97.8	4.09 × 10^−3	1.32 × 10^−2
	CFA8	HCl	15	1.73	SAS	28	075	3.02	0.12	97.6	2.23 × 10^−3	1.24 × 10^−2
	CFA8	HCl	20	1.73	SAS	33	227	4.09	0.22	97.9	4.51 × 10^−3	1.42 × 10^−2
	CFA8	HCl	25	1.73	SAS	29	117	3.79	0.21	97.9	4.12 × 10^−3	1.37 × 10^−2
Effect of reusing acid	CFA8	HCl (Reuse1)	20	1.73	SAS	32	301	4.43	0.27	97.8	4.25 × 10^−3	1.33 × 10^−2
	CFA8	HCl (Reuse2)	20	1.73	SAS	33	319	4.61	0.37	97.0	3.09 × 10^−3	9.37 × 10^−3
	CFA8	HCl (Reuse3)	20	1.73	SAS	28	317	4.39	0.21	96.8	2.39 × 10^−3	8.52 × 10^−3
	CFA8	HCl (Reuse4)	20	1.73	SAS	31	306	4.62	0.24	96.8	2.68 × 10^−3	8.63 × 10^−3
Effect of raw CFA	CFA1	HCl	20	1.54	SAS	23	461	4.79	0.32	97.4	2.59 × 10^−3	1.13 × 10^−2
	CFA2	HCl	20	1.81	SAS	29	371	4.65	0.29	98.0	4.11 × 10^−3	1.41 × 10^−2
	CFA3	HCl	20	1.84	SAS	27	363	4.54	0.29	97.9	3.75 × 10^−3	1.39 × 10^−2
	CFA4	HCl	20	1.82	SAS	32	381	4.72	0.32	98.7	5.64 × 10^−3	1.76 × 10^−2
	CFA5	HCl	20	1.83	SAS	32	301	4.43	0.25	97.8	4.25 × 10^−3	1.33 × 10^−2
	CFA6	HCl	20	1.80	SAS	28	372	4.86	0.24	98.8	4.99 × 10^−3	1.78 × 10^−2
	CFA7	HCl	20	1.73	SAS	21	360	4.89	0.26	98.5	3.44 × 10^−3	1.64 × 10^−2
	CFA8	HCl	20	1.75	SAS	31	301	4.85	0.27	98.6	5.35 × 10^−3	1.73 × 10^−2
	CFA9	HCl	20	1.73	SAS	31	322	4.54	0.28	98.0	4.42 × 10^−3	1.43 × 10^−2
Effect of Si/Al ratio	CFA8	HCl	20	0.54	Zeolite A	73	406	4.27	0.49	98.4	1.16 × 10^−2	1.59 × 10^−2
	CFA8	HCl	20	0.67	Zeolite A	67	413	4.28	0.61	98.5	1.13 × 10^−2	1.68 × 10^−2
	CFA8	HCl	20	0.82	Zeolite A	65	418	4.08	0.76	99.9	1.50 × 10^−2	2.31 × 10^−2
	CFA8	HCl	20	1.00	Zeolite A	63	408	4.10	0.57	98.6	1.08 × 10^−2	1.72 × 10^−2
Commercial molecular sieve 3A							450	2.76	0.32	98.7		1.72 × 10^−2
Commercial molecular sieve 4A							405	3.87	0.35	99.7		2.20 × 10^−2

Notes: CFA = coal fly ash; SAS = sodium aluminum silicate hydrate; A = adsorption capacity (from eq 2); a_sp = specific adsorption capacity (from eq 3).

4. X-ray diffraction of the original CFA (a), and the CFA after fusion with NaOH (b).

5. X-ray diffraction of zeolite products synthesized from CFA treated with various acids (a), various L/S ratios (b), and reusing acid (c).

6. Breakthrough curves of water adsorption by the zeolite products synthesized from CFA treated with various acid types (a), with various L/S ratios (b), and with reused acid (c).

7. Chemical compositions of zeolite products synthesized from various CFA.

8. X-ray diffraction of zeolite products, synthesized from CFA with the Si/Al ratio adjustment at laboratory scale.

9. SEM photographs of the zeolite samples synthesized from CFA without the Si/Al ratio adjustment (a) and with Si/Al ratio adjustment (b) at laboratory-scale experimentation.

10. Breakthrough curves of ethanol-water system during water adsorption by synthesized zeolite samples without the Si/Al ratio adjustment at laboratory scale (a), with Si/Al ratio adjustment at laboratory scale (b).

11. Breakthrough curves of water adsorption on zeolite product.

3. Estimated electrical production cost of zeolite synthesis

	Laboratory Scale				Large Scale
Electrical Process Requirement	Electrical Power (kW)	Time Used (hr)	Electricity Consumed (Unit)	Electricity Charge(US$)	Electrical Power(kW)	Time Used(hr)	Electricity Consumed (Unit)	Electricity Charge (US$)
Heater	0.415	2.5	1.04	0.09	1.00	2.5	2.50	0.21
Motor	0.415	12.0	4.98	0.42	0.44	44.5	19.58	1.65
Fan	—	—	—	—	0.37	44.5	16.467	1.39
Acid/alkali chemical pump	0.12	6.0	0.72	0.06	0.03	30.0	0.90	0.08
Kiln	1.60	28.0	44.8	3.77	1.60	28.0	44.8	3.77
Furnace	2.00	2.0	4.0	0.34	3.10	2.0	6.2	0.52
Total (US$/batch)				4.68				7.61
Total (US$/kg of zeolite)				359.68				5.08

Notes: The electrical production cost of the large scale was estimated using large-scale apparatus, whereas the electrical production cost of the laboratory scale was estimated using laboratory-scale apparatus. The electricity tariff (2.61 THB/kW or approximately 0.084 US$/kW for ≥69 kW) based on the Electricity Generating Authority of Thailand (EGAT), 2013.

4. Estimated material production cost of zeolite synthesis

	Laboratory Scale			Large Scale
Materials	Amount Used	Cost (US$/Unit)	Cost (US$)	Amount Used	Cost (US$/Unit)	Cost (US$)
HCl, 37%	0.27 L	4.90 US$/L	1.33	27.03 L	1.05 US$/L	28.33
Tap water	4.38 L	3.48 × 10^−2	1.4148 × 10^−3	107.97 L	3.48 × 10^−2	0.03
NaOH anhydrous pellet	22.50 g	US$/L	0.23	2.25 kg	US$/L	2.18
Al2O3 powder	6.77 g	10.32 US$/kg	0.28	0.34 kg	0.97 US$/kg	0.43
		41.94 US$/kg			1.26 US$/kg
Total (US$/batch)			1.84			30.97
Total (US$/kg of zeolite)			141.75			20.65

Notes: Material cost of the large-scale synthesis was based on the commercial price in Thailand, 2013, whereas material cost of the laboratory scale was based on the laboratory prices. The water tariff (0.01 THB/L or approximaltely 3.23 × 10⁻⁴ US$/L) based on The Metropolitan Waterworks Authority of Thailand (MWA), 2012.