抄録
In our country a lot of natural-gas brine, about 1,000,000 m3/day, is pumped out. It contains the same amount of NaCl and much less Mg2+ and Ca2+ compared with sea water, and nearly no SO42-. So, it must be a good raw material for salt making. In this paper, isothermal evaporation of such brine at 25°C was studied. For this purpose, the data of the heterogeneous equilibrium of the five components system, NaCl-KCl-MgCl2-CaCl2-H
2O were found in the table of D' Ans and the diagram was drawn on a tetrahedron axis, and the change of composition of the liquid phase due to evaporation was computed graphically. In such a way, only 6 species of salt crystals were found to come out by evaporation, namely, NaCl, KCl, MgCl2·KCl·6H2O, MgCl2·6H2O, 2MgCl2·CaCl2·12H2O and CaCl2·6H2O. The amoumt of water to be evaporated, the amount of crystals deposited, the amount and composition of the mother liquors obtained and the composition of the crystals gain was calculated.
The authors concluded that such brine was very suitable for salt making, because more and purer salt could be obtained compared with sea water.
