การเก็บกลับคืนแมกนีเซียมไฮดรอกไซด์จากน้ำขมของการผลิตเกลือสมุทรโดยใช้แคลไซน์โดโลไมท์ / ณัฐพร สุขพลอย = Recovery of magnesium hydroxide from salt field brine using calcined dolomite / Natthapawn Sookploy
Salt production from sea water in Thailand by solar evaporation ponds, produced waste brine or bitterns. This waste brine was analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analysis showed the presence of sodium (Na⁺), magnesium (Mg²⁻), sulphate (SO₄²⁺), calcium (Ca²⁺), potassium (K⁺) and chloride (Cl-) which magnesium chloride (MgCl₂) is the major component. In various parts of the world, process technologies have been developed to recover these chemicals directly from salt field brine or from bitterns which is the waste or spent brine after harvesting of salt crystallized by solar evaporation of sea water. Magnesium hydroxide (Mg(OH)₂) is a valuable chemical produced from sea water and its bitterns through precipitation process. In this study, the recovery of magnesium hydroxide from salt field waste brine waste was investigated using calcined dolomite. The magnesium hydroxide precipitated was analyzed by X-ray fluorescence (XRF) and compared with magnesium hydroxide precipitation from the synthetic magnesium chloride. The effects of magnesium ion (Mg²⁺) concentration, solid-liquid ration and dolomite particle size on magnesium hydroxide precipitation rate were also determined at room temperature using calcined dolomite at 950°C.