Phosphogypsum density
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I recently conducted some experiments on phosphogypsum; the density of the wet gypsum (the gypsum produced during the production of phosphoric acid using the dihydrate method) was 0.936 g/ml (with a moisture content of 30.7%). After washing and drying, the density of the dry powdered gypsum was found to be 0.63 g/ml. I found online that the density of phosphogypsum is 2.3 g/ml. Could someone please explain why this is the case?
The densities of the wet and dry phosphogypsum you measure should be bulk densities; the volume used in the calculations includes voids, whereas the true density (2.3 g/ml) does not include such voids.
It’s the bulk density! :） The laboratory equipment is quite simple; only a balance and a measuring cylinder were used. Is there any way to measure the density of gypsum?
This can be done using a measuring cylinder: first, add to the cylinder a liquid that does not dissolve gypsum and has a lower specific gravity than gypsum; record the initial volume. Then, add the weighed gypsum to the cylinder and record the final volume. The volume of the gypsum is obtained by subtracting the initial volume from the final volume. Finally, mass divided by volume gives density.
Following the method for determining the density of cement, and using a Lee hydrometer along with anhydrous kerosene, we determined that the density of building gypsum is approximately 2.6 g/cm3