My phosphogypsum research. Part 1

First time I heard about phosphogypsum was in some 2011. I read an article, and it said phosphogypsum is unused industrial waste and also it contains rare-earth elements. I thought that REE sounds interesting and I would like to extract REE from phosphogypsum. I was thinking for several days about such extraction and was reading about phosphogypsum. Phosphogypsum mostly contains gypsum, and I realized that the optimal way is extracting pure gypsum. Pure gypsum can be sold easily, and after extracting it from phosphogypsum REE extraction becomes more simple.

So, the goal is to extract pure gypsum from phosphogypsum.

But how to extract gypsum? I assumed that dissolution and precipitation can do it. While gypsum is dissolved it can be purified.

So, the goal is to dissolve gypsum and then precipitate it.