Manufacturing process for light magnesium carbonate

Abstract

The invention relates to a manufacturing process for light magnesium carbonate, in particular to a manufacturing process for light magnesium carbonate by adopting calcium lime and magnesium sulfate solution produced during the wet process metallurgy. The process comprises the following steps of: slaking calcium lime to obtain lime cream; using the lime cream for precipitating magnesium to ensure that crystalline calcium sulphate and gelatinous magnesium hydroxide are precipitated out; separating the calcium sulphate from the magnesium hydroxide to obtain calcium sulphate pulp and magnesium hydroxide pulp; feeding carbon dioxide into the magnesium hydroxide pulp to obtain magnesium bicarbonate solution; heating the magnesium bicarbonate solution to ensure that magnesium bicarbonate is decomposed to generate basic magnesium carbonate and release carbon dioxide; and filtering the basic magnesium carbonate out, washing and drying to obtain the light magnesium carbonate. The manufacturing process has the advantages that the manufacturing process is simple, the cost is low, and the waste liquor produced during the wet process metallurgy can be treated.

Description

technical field [0001] The present invention relates to a preparation process of light magnesium carbonate, in particular to a process for preparing light magnesium carbonate by using magnesium sulfate and quicklime, more specifically, to a process for purifying and removing leaching liquid by using quicklime and hydrometallurgy. Miscellaneous, the process of preparing light magnesium carbonate from the magnesium sulfate solution after recovering valuable metals such as copper and nickel. Background technique [0002] Light magnesium carbonate, also known as basic magnesium carbonate, white monoclinic crystal or amorphous powder, non-toxic, odorless, stable in the air, its molecular formula is roughly (3-5) MgCO 3 ·Mg(OH) 2 ·(3-7)H 2 O, slightly soluble in water, weakly alkaline, solubility in water is 0.02% at 15°C, soluble in acid and releases carbon dioxide, decomposes above 300°C to form magnesium oxide. [0003] Light magnesium carbonate is an important chemical prod...

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Problems solved by technology

[0013] For example, when high-pressure sulfuric acid leaching or normal-pressure acid leaching is used to extract nickel from laterite ore, the content of magnesium in the leaching solution is usually 3-5 times that of nickel. It is very difficult to treat the wastewater in inland areas where magnesium sulfate cannot be discharged directly. and expensive

High-magnesium and low-grade nickel concentrates cannot be smelted due to high magnesium content, and a large amount of magnesium is dissolved when wet treatment is used, and there is also the problem of magnesium-containing wastewater treatment

[0014] The above-mentioned traditional carbonization method utilizes quicklime and magnesium chloride to prepare light magnesium carbonate. However, magnesium sulfate in the hydrometallurgical leaching solution cannot be used to prepare light magnesium carbonate. It can only be discharged (seaside) or treated as wastewater (inland)

Although the traditional soda ash method can utilize sodium carbonate and magnesium sulfate to prepare light magnesium carbonate, the price of sodium carbonate is higher, thereby increasing the cost of the whole preparation process

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