Question

Raw gypsum from a fertilizer plant is being leached out of its salt (NaCl) content in a 2-step continuous countercurrent system using salt-free water as leaching medium. The underflow, CaSO4 slurry is then sent to a drier to obtain the final product. The operating data are as follows:

Raw gypsum feed = 10 MT/day

Salt content of raw gypsum = 1 wt%

Water feed rate = 90 m3/day

Water content of slurry = 0.09 MT H2O per MT CaSO4

Questions:

1. The percent of salt removed in the process is?

2. The resulting salt content in the overflow in weight percent is?

Answer 1

(90×100)÷100 = 90%