Removal of Major Impurties (Ca-Mg) of Brine with Chemical Treatment Process in the Salt Sector

Abstract

The operation of salt minerals dates back hundreds of years. Salt is produced from salt rich sources through salts today. The salt (brine) obtained from existing salt sources is not in the desired purity. For this purpose, purification of the brine should be carried out to remove unwanted impurities. Brine (raw salt) also contains impurities that are soluble and insoluble except NaCl. 94-96% of the brine obtained from the salt lake contains NaCl. The remaining 4-6% are MgCl2, MgSO4, CaCl2 and other trace amounts. All of these substances are called solubility and insoluble impurities. These impurities are magnesium, calcium and sulfate .Calcium accumulation causes crust formation in the circulation line, especially heat exchangers. For this reason, heat transfer and circulation effiency decrease. The impurities from the dissolved raw salt (Ca+2, Mg +2 etc.) should be removed by the purification process. Settling tests were carried out in brine purification system. As the experimental results obtained, the magnesium and calcium from the major impurities in the brine were separately and coherently removed. NaOH was used to precipitate the magnesium and the dynamic run-out was determined to be optimum pH = 11. Na2CO3 was used to precipitate the calcium from the other major impurities in the brine. As a result of dynamic experiments, optimum precipitation pH was set at 9,5.

Keywords

• raw salt (brine),chemical treatment,pH adjustment

References

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