REGYP Recycled Gypsum products recently excelled in the Pacific Fertiliser eastern seaboard gypsum comparison research.
PacFert invested a lot of time and money testing many sources of Australian gypsum for quality, sizing and solubility. Super AG Gypsum derived from plasterboard was up against gypsum from numerous other natural mined sources available on the eastern seaboard.
The analysis of the gypsum samples were carried out by the Cement Australia’s laboratory in Darra, Brisbane QLD. Gypsum samples for each source were gained from the miner/manufacturer or from the field customer. All samples were gathered in March 2015.
Gypsum Solubility Test Method: The solubility of the gypsum tested is based on a practical method reflected more on what happens in the field not standard laboratory solubility tests for minerals. The measured solubility is expressed in units of electrical conductivity (dS/m). The electrical conductivity (EC) of the solution is measured after adding the equivalent of 10g of 100% CaSO4.2H2O (gypsum) to 1 litre of demineralised water and shaking 20 times end over end. In this test no grinding of the gypsum products have been carried out before testing the EC of the gypsum in solution. This method was found in the NSW Dept Agriculture, Ag Facts article where they compared various gypsum sources in 1996.
Pacific Fertiliser also employed a correction factor for salt levels in the gypsum and their effect on the measured gypsum solubility. The higher the salt content the higher the electrical conductivity of the sample in solution.
Fine the results below and on the following link gypsum comparison.