As an industrial by-product gypsum, FGD gypsum also has some properties of chemical gypsum,
usually contains about 8%~12% attached water, particle size distribution is relatively concentrated,
with a diameter between 30~60μm, the value of pH is generally around 5~9[2]. In addition, its
physical properties and chemical composition (natural gypsum case in Shanxi Xishan mine)
compared to natural gypsum is quite different, as shown in Table 2 and Table 3 below.