Method for preparing light magnesium carbonate

Abstract

The invention relates to a method used for preparing light magnesium carbonate. The invention belongs to the field of ultra-fine particle preparation. First, a magnesium chloride solution is heated to a temperature of 50-90 DEG C, and the solution is added into a hypergravity reactor; simultaneously, a mixed gas containing NH3 and CO2 gases is delivered into the reactor; the solution contacts the mixed gas by a counter current manner in the reactor; the solution is circularly fed, and a circulated mixed absorbing reaction of MH3 and CO2 is carried out in the hypergravity reactor; after the reaction, the solution is filtered, and ammonia ions and chloride ions are removed by washing by using deionized water; the obtained material is dried by baking under a temperature of 110 DEG C, such that light magnesium carbonate is prepared. The concentration of magnesium chloride is 0.1-1mol / L, the operation pressure is normal pressure which is 1atm, and the hypergravity level is 118-600g. With the method provided by the invention, rapid, microscopic, and uniform mixing can be realized, such that a homogeneous nucleation condition required by the preparation of light magnesium carbonate can be reached. According to the invention, the process is easy to control, and aging is not required. The method provided by the invention is advantaged in simple technology and high efficiency. The method can easily be applied in large-scale productions.

Description

technical field [0001] The invention relates to a preparation method of light magnesium carbonate, in particular to the preparation of light magnesium carbonate by gas-liquid rapid mixing reaction precipitation, which belongs to the field of ultrafine particle preparation. Background technique [0002] Light magnesium carbonate is made from MgCO 3 , Mg(OH) 2 and H 2 O is composed of a certain molar ratio and is a white crystal or amorphous powder, non-toxic, odorless, and stable in the air. Its molecular formula is xMgCO 3 ·yMg(OH) 2 ·zH 2 O (wherein x=1~4, y=0~1, z=0~8). Light magnesium carbonate is slightly soluble in water, which can make the water weakly alkaline. When boiled in water for a long time, part of it will be decomposed into magnesium hydroxide. It is easily soluble in acid and ammonium salt solution, foams and decomposes when it encounters dilute acid, and releases CO 2 . When heated above 300°C, water and carbon dioxide are decomposed to produce mag...

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Problems solved by technology

[0048] This method can obtain the very high light magnesium carbonate of purity, and product crystal form is easy to control, is a kind of effective method of preparing special light magnesium carbonate, but, this method needs to control the pH value, CO in the reaction. 2 The amount of injection, and the raw material magnesium hydroxide must be prepared first, the operation process is more complicated, and the production cost is higher

[0049] The above-mentioned methods all have the disadvantages of low purity, low economy and low environmental benefit.

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