Method for recovering elemental magnesium and elemental calcium from magnesium sulfate solution

A magnesium sulfate and magnesium chloride solution technology, applied in chemical instruments and methods, magnesium carbonate, calcium/strontium/barium sulfate, etc., can solve the problems of resource waste, magnesium and calcium cannot be effectively used at the same time, etc.

Active Publication Date: 2017-11-21
CHINA ENFI ENGINEERING CORPORATION
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  • Description
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  • Application Information

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Problems solved by technology

[0004] The main purpose of the present invention is to provide a method for reclaiming magnesium element and calcium element from magnesium sulfate solution, so as to solve the problem t

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  • Method for recovering elemental magnesium and elemental calcium from magnesium sulfate solution

Examples

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Effect test

Embodiment 1

[0033] React 1000mL24g / L magnesium sulfate solution with calcium chloride and thicken to obtain 800mL24g / L magnesium chloride solution (overflow) and 340g gypsum pulp (underflow), the molar ratio of magnesium sulfate to calcium chloride is 1:1 .

[0034] Make above-mentioned magnesium chloride solution and the lime milk that solid content is 10wt% carry out metathesis reaction, obtain calcium chloride dilute solution and 1 magnesium hydroxide, wherein the ratio of the magnesium chloride in the magnesium chloride solution and the calcium hydroxide mole number in the lime milk is 1:1.05 .

[0035] The above-mentioned magnesium hydroxide and carbon dioxide were carbonized at 25° C. to obtain 1000 mL of 1 mol / L magnesium bicarbonate solution.

[0036] According to the molar ratio of the calcium ion in the magnesium bicarbonate solution and the decalcifying agent (sodium hydroxide) is 1:5, the above-mentioned magnesium bicarbonate solution and the decalcifying agent (sodium hydrox...

Embodiment 2

[0040] The difference from Example 1 is that during the neutralization reaction, the molar ratio of magnesium sulfate to the calcium chloride is 1:3. The result is that the calcium ions in the magnesium chloride solution obtained by the neutralization reaction are excessive, resulting in waste of calcium chloride, and a large amount of decalcifying agent needs to be consumed to remove the excess calcium ions in the subsequent process.

Embodiment 3

[0042] The difference with Example 1 is that in the metathesis reaction, the magnesium chloride solution and the 5wt% calcium hydroxide aqueous solution are subjected to the metathesis reaction. The result is the whole metathesis reaction process, the volume expansion of the reaction system is too large, and limited by the inherent volume of the reaction device, the calcium hydroxide aqueous solution of the above-mentioned percentage content is unfavorable for shortening the reaction cycle.

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Abstract

The invention provides a method for recovering elemental magnesium and elemental calcium from a magnesium sulfate solution. The method comprises the following steps: subjecting a magnesium sulfate solution and calcium chloride to a neutralization reaction so as to obtain a magnesium chloride solution and gypsum, wherein the magnesium sulfate solution contains calcium ions; subjecting the magnesium chloride solution and calcium hydrate to a metathesis reaction so as to obtain a calcium chloride solution and a crude magnesium hydroxide product; subjecting the crude magnesium hydroxide product and carbon dioxide to a carbonization reaction so as to obtain a magnesium bicarbonate solution; and subjecting the magnesium bicarbonate solution to a thermal decomposition reaction so as to obtain basic magnesium carbonate. The method provided by the invention can recover both elemental calcium and elemental magnesium in the magnesium sulfate solution, and the recovered elemental calcium and elemental magnesium are both high in purity.

Description

technical field [0001] The invention relates to the field of hydrometallurgy, in particular to a method for recovering magnesium element and calcium element from magnesium sulfate solution. Background technique [0002] At present, in many industrial fields, a large amount of waste liquid containing magnesium is often produced. Likewise, acid leaching of magnesium-bearing ores in hydrometallurgical processes produces large quantities of solutions containing magnesium sulfate. Magnesium sulfate, also known as "bitter water", is a toxic substance that can cause diarrhea in humans. Therefore, the country prohibits the direct discharge of wastewater containing magnesium sulfate. [0003] There are mainly two ways to treat wastewater containing magnesium sulfate: one is to make magnesium sulfate heptahydrate through evaporation and concentration, cooling and crystallization, which is the commonly used magnesium fertilizer in China; the other is to prepare magnesium hydroxide by ...

Claims

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Application Information

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IPC IPC(8): C01F5/24C01F11/46C30B29/46C30B7/10C30B29/62
CPCC01F5/24C01F11/46C30B7/10C30B29/46C30B29/62
Inventor 孙宁磊彭建华刘国
Owner CHINA ENFI ENGINEERING CORPORATION
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