Evaluation of different methods for gypsum determination in artificial soil

	Evaluation of different methods for gypsum determination in artificial soil
Journal of Tikrit University For Agriculture Sciences
Article 1, Volume 13, Issue 2, 2013, Pages 367-374
Abstract
The aim of this study was to evaluate three different methods to estimate Gypsum (CaSO4.2H2O) by using pure sand (silica sand), after gypsum addition at 5, 10, 15, 25, 50, and 70% level. The first method is based on titration and chelating as described by (Lagerwerff et al.1965). While the second method is based on gypsum dissolving of and precipitation as Barium Sulfate (ASTM,1988). The third method used the crystalline water loss from aqueous calcium sulfate (Gypsum) (Artieda et al.2006) method. The results showed that the ASTM method gave the higher value with the low level of gypsum (5%) which was 4.69%, while the other methods Artieda and Lagerwerff , gave 4.66% and 4.472% respectively. Lagerwerff method gave higher result than Artieda and the ASTM methods for the level 10%. Lagerwerff method gave a percent of gypsum which was 9.528% while Artieda and the ASTM methods gave 9.479% and 9.146% respectively. The results from this study showed that Artieda method is better than both Lagerwerff and the ASTM methods in estimating of gypsum at medium and high levels (15%, 25%, 50%, and 70%), as they gave the percents 14.604%, 24.626% , 49.412% and 69.242%, respectively. While Lagerwerff method gave the following values 14.418%, 24.389%, 48.966%, and 68.714%, the ASTM method gave the values 14.011%, 24.276%, 48.806% and 68.582% respectively with the same levels; 15%, 25%, 50%, and 70% .
Keywords
methods of gypsum Determination; gypsum; hydrated calcium sulfate

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