Brief introduction
The brine process is a process for extracting magnesium from seawater or salt lake water, where the product is basic magnesium carbonate (MgCO3-Mg(OH)2-3H2O).
Process Flow
The process flow for the preparation of magnesium basic carbonate by the brine method includes the following main steps:
Brine extraction: extract brine rich in magnesium ions from seawater or salt lake water.
Purification pretreatment: Remove impurities in the brine, such as calcium ions, sulfates and heavy metals.
Calcium Carbonate Precipitation: Magnesium bicarbonate (Mg(HCO3)2) is precipitated as calcium carbonate (CaCO3) by adding lime (CaO) or calcium hydroxide (Ca(OH)2) to the brine.
Filtration: Separation of the calcium carbonate precipitate.
Carbonation: Carbon dioxide (CO2) is introduced into the filtrate to precipitate the remaining magnesium ions as basic magnesium carbonate.
Filtration: The filtrate is filtered again and the magnesium carbonate basic product is separated.
Chemical reaction
Precipitation of calcium carbonate:
CaO + Mg(HCO3)2 → CaCO3 + Mg(OH)2
Carbonation:
Mg(OH)2 + CO2 + H2O → MgCO3-Mg(OH)2-3H2O
The parameters of the process of preparing basic magnesium carbonate by brine method include:
Concentration and composition of the brine
Carbonation reaction temperature and pressure
Precipitation rate of calcium carbonate
Type and flow rate of carbonation gas
Product Quality
The quality of magnesium basic carbonate prepared by the brine method depends on the control of the process parameters as well as the purity of the brine. The target product should have the following characteristics:
Magnesium content: approx. 42-46
Calcium carbonate content: less than 1%
Impurity content: less than 0.5%
Whiteness: greater than 90%
Basic magnesium carbonate is widely used in the following fields:
Pharmaceutical industry: antacid, laxative
Food industry: preservative, coagulant
Chemical industry: manufacture of magnesium oxide, flux
Building material industry: fireproof material, heat insulation material
