Method for preparing ultra-fine calcium oxide with dolostone

A technology of calcium oxide and acidizing solution, applied in the direction of calcium/strontium/barium oxide/hydroxide, etc., can solve the problem of low development and utilization of dolomite, and achieve the effects of environmental protection, uniform particles, and low price

Inactive Publication Date: 2008-12-10
ZHEJIANG UNIV
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  • Abstract
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Problems solved by technology

However, the development and utilization of dolomite in my country is very low at present, and most mines only sell raw ore

Method used

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specific Embodiment approach

[0014] The invention proposes a method for preparing superfine calcium oxide from dolomite, the preparation process is simple and the production cost is low. The specific implementation method comprises the following steps:

[0015] The first step of preparation is to take 100 grams of fully crushed dolomite and calcinate it in a furnace at 900-1600°C for 3-8 hours. During the calcining process, the dolomite gradually removes CO 2 , forming calcined dolomite powder with the general chemical structure formula (Mg, Ca)O, which contains a small amount of SiO 2 , Fe 2 o 3 、Al 2 o 3 and other secondary components.

[0016] MgCa(CO 3 ) 2 →MgO+CaO+2CO 2 ↑

[0017] Take another 100-150 grams of fully broken dolomite, add it to 1-4 liters of 0.5-2mol / L hydrochloric acid solution, stir and react for 0.5-3 hours, and filter off the insoluble residue to obtain MgCl 2 and CaCl 2 The dolomite acidizing solution is the main one; the contents of Ca and Mg elements in the acidizing ...

Embodiment 1

[0027] 1) Calcining 100 grams of fully crushed dolomite powder in a furnace at 900° C. for 8 hours to obtain a dolomite calcined product whose general chemical structure is (Mg, Ca)O;

[0028] 2) Add 100 grams of fully crushed dolomite powder into 1 liter of 2mol / L hydrochloric acid solution, stir and react for 3 hours, filter out insoluble residues, and obtain dolomite acidification solution;

[0029] 3) Add the dolomite calcined product to 1000mL 30°C deionized water for digestion; remove the residue, add dolomite acidification solution, stir and react for 0.5 hours, centrifuge, wash with water, and dry in solid phase to obtain ultrafine magnesium hydroxide powder;

[0030] 4) Slowly drop 5 liters of 0.4N NaOH solution into the above separation liquid, and add 0.5 g of polyethylene glycol, react in a water bath at 90°C for 0.5 hours, centrifuge, wash with water, dry the solid phase product, and dry at 600°C Calcined in the furnace for 8 hours, cooled to obtain superfine cal...

Embodiment 2

[0032] 1) Calcining 100 grams of fully crushed dolomite powder in a furnace at 1600° C. for 3 hours to obtain a dolomite calcined product whose general chemical structure is (Mg, Ca)O;

[0033] 2) Add 150 grams of fully crushed dolomite powder into 4 liters of 0.5 mol / L hydrochloric acid solution, stir and react for 0.5 hour, filter off the insoluble residue, and obtain dolomite acidification solution;

[0034] 3) Add the dolomite calcined product to 200mL deionized water at 90°C for digestion; remove the residue, add dolomite acidification solution, stir and react for 3 hours, centrifuge, wash with water, and dry in solid phase to obtain ultrafine magnesium hydroxide powder;

[0035] 4) Slowly drop 0.5 liters of 4N KOH solution into the above separation liquid, and add 5 grams of citric acid, react in a water bath at 50°C for 5 hours, centrifuge, wash with water, dry the solid phase product, and calcinate in a furnace at 900°C After cooling for 2 hours, superfine calcium oxi...

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Abstract

The invention discloses a method for preparing superfine calcium oxide from dolostone. The dolostone has very rich reserves in China, and the main composition of the dolostone is dolomite with a chemical formula MgCa(CO3)2. The method comprises the following simple steps: firstly, separation of calcium and magnesium is realized through reaction between dolostone calcined powder and dolostone acidizing fluid; and secondly, an alkaline solution is dripped into a calcium chloride solution obtained after separation of the calcium and the magnesium, and activated superfine calcium oxide powder is obtained after calcination of obtained calcium hydroxide granules. The superfine calcium oxide is widely applied in the fields such as fire retardant, absorbent, filler and so on. The method for preparing the superfine calcium oxide provided by the invention has a simple technological flow, small equipment investment, and low operating cost; the purity of the prepared calcium oxide is over 90 percent, and superfine magnesium hydrate powder with economic value is simultaneously obtained; and the method is an economic and effective method for preparing the superfine calcium oxide.

Description

technical field [0001] The invention relates to a method for preparing compounds, in particular to a method for preparing superfine calcium oxide from dolomite. Background technique [0002] Dolomite is an important calcium and magnesium resource on the earth, and it has extremely rich reserves in my country. However, the development and utilization of dolomite in my country is very low at present, and most mines only sell raw ore. [0003] Due to its high specific surface area, high activity and strong adsorption capacity, ultra-fine CaO has been used to replace lime milk solution to treat high-concentration fluorine-containing wastewater, and can adsorb mercury and mercuric chloride in wastewater. Because CaO is cheap and rich in raw materials, it is also widely used as a sulfur fixing agent in desulfurization technology, which can effectively remove H 2 S and COS. Its high adsorption capacity, low preparation cost, long cycle life and good anti-wear properties make it ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/06
Inventor 叶瑛陈雪刚吕双双夏枚生张路姚志通李秀悌
Owner ZHEJIANG UNIV
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