A high-efficiency and energy-saving heavy magnesium water pyrolysis method

Abstract

The invention discloses that the invention relates to a high-efficiency and energy-saving heavy magnesium water pyrolysis method. After the heavy magnesium water is atomized through an atomization device, it is contacted with high-temperature hot air to complete mixing, heating, and decomposition. The atomized heavy magnesium The water and the high-temperature hot air are in a countercurrent direction. After the sufficient pyrolysis reaction, the gas-liquid separation is completed in the separator, and then the solid-liquid separation is carried out. The obtained solid basic magnesium carbonate crystallizes, and after drying, a pure white high-swelling alkali is obtained. formula magnesium carbonate. The invention has short technological process, continuous and stable production, no need for cleaning, long operation period, easy production operation, low production cost, simple equipment, low fixed investment, excellent operation effect in pilot plant, and industrial application conditions.

Description

technical field [0001] The invention relates to a high-efficiency and energy-saving heavy magnesium water pyrolysis method, in particular to a method for producing high-bulking magnesium carbonate by carbonization of dolomite or magnesite. Background technique [0002] The aqueous solution of magnesium bicarbonate is commonly called heavy magnesium water, and magnesium bicarbonate is an unstable weak acid salt. The pyrolysis referred to in the present invention is that heavy magnesium water is heated and decomposed into basic magnesium carbonate precipitation (also known as light magnesium carbonate) and The process of releasing carbon dioxide. The main reaction formula is as follows: 5Mg(HCO 3 ) 2 +nH 2 O=4MgCO 3 ·Mg(OH) 2 4H 2 O↓+6CO 2 ↑+nH 2 O. [0003] In industrial production, the concentration of magnesium in heavy magnesium water is low, usually 8-15g / L (calculated as MgO). It takes a lot of heat energy to heat and pyrolyze a large amount of aqueous solution,...

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Problems solved by technology

[0003] In industrial production, the concentration of magnesium in heavy magnesium water is low, usually 8-15g / L (calculated as MgO). It takes a lot of heat energy to heat and pyrolyze a large amount of aqueous solution, while the traditional pyrolysis temperature is 95-105°C. Its energy consumption accounts for more than 60% of the entire magnesium salt production. The current pyrolysis technology has made some continuous improvements to the traditional pyrolysis technology: one is to improve the continuous production of negative pressure and realize low-temperature continuous production; Utilize low-level heat energy to achieve graded utilization of heat energy, but they are all slightly modified on the basis of the original device, and no major changes have been achieved in terms of production input and overall operating efficiency.

[0004] Such as patent CN200910180206.6 (special device for continuous production of light magnesium carbonate by low-pressure pyrolysis), still need to use boiler and vacuum pump, and the thermal efficiency of boiler is low, as a kind of hot water boiler, directly heat heavy magnesium water, long-term use Afterwards, it is easy to foul, the heat transfer effect is worse, and the thermal efficiency is lower. The vacuum pump consumes a lot of power, the system is negative pressure, and the investment of the whole device is also large. Although the production cost is lower than that of the traditional device, the overall cost is still high. , industrial production can not show benefits

[0005] Such as patent CN201210147887.8 (method and device for producing basic magnesium carbonate by pyrolyzing heavy magnesium water) in its embodiment involves 20g / L, even reaches 100g / L heavy magnesium water containing magnesium oxide concentration, to produce such high concentration Heavy magnesium water itself requires a high cost, which does not meet the reality of industrial production; or involves high-temperature liquid at 90°C, which is difficult to achieve with low heat energy, or requires high cost to achieve

For the utilization of low-level heat energy, thermal media such as molten salt and heat-conducting oil are also taken into consideration. In this way, a single device for obtaining low-level heat energy requires a large amount of capital investment, which is higher than that of a coal-fired boiler with the same power, so the fixed investment of the entire pyrolysis device is very large. The production cost saved is not enough to offset the depreciation of equipment, and the production cost is too high

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