What is the Difference Between Gypsum and Phosphogypsum?

The main difference between gypsum and phosphogypsum lies in their origins and radioactivity. Both gypsum and phosphogypsum are forms of calcium sulfate, specifically dihydrated calcium sulfate (CaSO4·2H2O). However, gypsum is a naturally occurring form of calcium sulfate, while phosphogypsum is a synthetic form obtained as a by-product during the production of superphosphate from phosphate rock.

Some key differences between gypsum and phosphogypsum include:

1. Origin: Gypsum is a rock-forming, soft crystal obtained by mining or quarrying, whereas phosphogypsum is a by-product of phosphate production from phosphate rock.
2. Radioactivity: Phosphogypsum is slightly more radioactive than natural gypsum due to the presence of naturally occurring uranium and its daughter isotopes radium, radon, and polonium. This radioactivity makes phosphogypsum less suitable for use in the construction industry and requires careful storage.
3. Utilization: Gypsum is widely used in the construction industry for applications such as wallboard and cement production. In contrast, phosphogypsum has a low utilization rate due to its large discharge, complex impurity composition, and difficult treatment.

In summary, gypsum and phosphogypsum are both forms of dihydrated calcium sulfate, but they differ in their origins, radioactivity, and utilization. Gypsum is a naturally occurring form of calcium sulfate, while phosphogypsum is a synthetic form obtained as a by-product during the production of superphosphate from phosphate rock. Gypsum is widely used in the construction industry, whereas phosphogypsum has a low utilization rate and requires careful storage due to its radioactivity.

Comparative Table: Gypsum vs Phosphogypsum

Here is a table summarizing the key differences between gypsum and phosphogypsum:

Gypsum is a naturally occurring form of calcium sulfate, while phosphogypsum is a synthetic form of calcium sulfate produced as a by-product during the production of superphosphate from phosphate rock. Gypsum is primarily used in the construction industry, whereas phosphogypsum is usually not used and stored indefinitely due to its weak radioactivity caused by the presence of naturally occurring radionuclides such as radium (Ra), radon (Rn), and polonium (Po).