Influence of Seed Crystal and Modifier on the Morphology of α-calcium Sulfate Hemihydrate Prepared by Salt Solution Method in Pilot Scale

Abstract:

Article Preview

Preparation of α-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum is of great value in effectively utilizing the FGD gypsum. This paper focuses on the effect of seed crystal and some modifiers on the morphology of α-HH on a 500-1000 kg/batch setup based on a salt solution method established on the previous work. The pilot tests were carried out in a Ca-Mg-K chloride solution medium at 94 oC (±2 oC) under atmospheric pressure. The results show that a small amount of seeds is advantageous to prepare short-prism α-HH but results in needle-like and spherical crystals in the case of more than 1% addition. The well-shaped α-HH crystals can also be obtained by adding appropriate amounts of crystal modifiers like Fe3+ and the mixed salts of Al3+ and organics.

Info:

Periodical:

Advanced Materials Research (Volumes 168-170)

Edited by:

Lijuan Li

Pages:

8-12

DOI:

10.4028/www.scientific.net/AMR.168-170.8

Citation:

B. Kong et al., "Influence of Seed Crystal and Modifier on the Morphology of α-calcium Sulfate Hemihydrate Prepared by Salt Solution Method in Pilot Scale", Advanced Materials Research, Vols. 168-170, pp. 8-12, 2011

Online since:

December 2010

Export:

Price:

$35.00

[1] Apageorgiou A, Tzouvalas G, Tsimas S: Cement Concrete Comp, Vol. 27 (2005), p.183.

[2] R. B. Clark, S. K. Zeto, K. D. Ritchey, and V. C: Fuel, Vol. 76 (8) (1997), p.771.

[3] Hamm H, Kersten HJ, Hueller R: Sonderdruck aus, Vol. 4 (2004), p.92.

[4] D. C. S. E. C. Combe: J Appl Chem, Vol. 18 (10) (1968), p.307.

[5] ALFRED Zürz, IVAN Older, FELICIA Thiemann: J Am Ceram Soc, Vol. 74 (1991), p.1117.

[6] Zheng W, Zhang J: Non-Metallic Mines, Vol. 29(4) (2006), p.1. (In Chinese ).

[7] Y. Ling, 'Direct Preparation of Alpha-Calcium Sulfate Hemihydrate from Sulfuric Acid',; Ph.D. Thesis, McGill University, Canada, (2004).

[8] Guan B, Yang L, Wu Z. Fuel, Vol 88 (2009), p.1286.

[9] P. Wang, E. -J. Lee, C. -S. Park, et al: J Am Ceram Soc, Vol. 91(6) (2008), p.2039.

[10] C. Philip, G. T. R. Tseng: Environ Prog, Vol. 5(1) (1986), p.5.

[11] Kubota N, Otosaka H, Doki N, Yokota M, Sato A: J Cryst Growth, Vol 220 (2000), p.135.

[12] Murphy CJ: Science, Vol 298 (2002), p.2139.

In order to see related information, you need to Login.