| 摘要 |
PURPOSE:To produce economically Glauber's salt, by crystallizing the Glauber's salt from iron sulfate and inexpensive rock salt or industrial salt as a raw material utilizing the solubility difference at the temperature of the Glauber's salt without using the crystallization step of the Glauber's salt depending on concentration of a Glauber's salt solution. CONSTITUTION:Iron sulfate is mixed or granulated with sodium chloride, and the granulated material is then roasted at >=400 deg.C in the presence of oxygen and steam to give a roasted material consisting essentially of iron oxide and Glauber's salt. The roasted material (A) from a roasting furnace 1 is cooled in a cooler 2, and then charged into a leaching tank 3. The Glauber's salt in the roasted material is dissolved in a separating solution cooled in a cooler 9 and additional water (B) to form a Glauber's salt solution slurry of iron oxide. The leaching tank 3 is kept at 33-35 deg.C at which the solubility of the Glauber's salt is highest. The iron oxide (C) is then separated from the above-mentioned slurry in a filter 4. The formed Glauber's salt mother liquor (D) is fed to heaters 5 and 6 and heated at 60 deg.C to crystallize the Glauber's salt. The complete deposition of crystals and concentration are carried out in a crystallization tank 7 to separate the crystals in a separator 8. The separated solution (F) of the crystallization tank 7 and separated solution (G) of the separator 8 are subjected to heat exchange with the mother liquor (D) in the heater 5 passed through the cooler 9 and then returned to the leaching tank 3.
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