CN100368295C - Method for producing light magnesium carbonate by utilizing magnesite tailings - Google Patents
Method for producing light magnesium carbonate by utilizing magnesite tailings Download PDFInfo
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- CN100368295C CN100368295C CNB2004101004044A CN200410100404A CN100368295C CN 100368295 C CN100368295 C CN 100368295C CN B2004101004044 A CNB2004101004044 A CN B2004101004044A CN 200410100404 A CN200410100404 A CN 200410100404A CN 100368295 C CN100368295 C CN 100368295C
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- magnesium carbonate
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Abstract
The present invention relates to the production of light magnesium carbonate, particularly to a method for producing light magnesium carbonate by magnesite tailing. The present invention has the detailed process that ore is crushed, the crushed particle size is from 5 to 30cm, and the crushed ore can be put in a lime kiln for calcination; calcined magnesite blocks are ground into 150 to 200 mesh; MgO powder which is well ground is added with water, is sunk in materials, and is digested into magnesium hydrate emulsion; the magnesium hydrate emulsion and CO2 carry out the carburizing reagent so that Mg (OH) 2 emulsion forms magnesium carbonate emulsion; the magnesium carbonate emulsion after reaction is put in a settling pond, is settled, and is filtered to obtain heavy magnesium water; the heavy magnesium water is pyrolyzed at 95 to 105 DEG C so as to form crystal granules; a finished product can be obtained through filtration and drying. The present invention has the advantages of low production cost, simple process, good product quality and no pollution.
Description
Technical Field
The invention relates to the production of light magnesium carbonate, in particular to a method for producing light magnesium carbonate by utilizing magnesite tailings.
Background
The main component of magnesite ore is MgCO3And also contains unequal amounts of Fe2O3·Al2O3With SiO2And the like. Because the concentrate is not ubiquitous, in the process of mining the existing magnesite tailings (MgO, naturally existing) in China, the special-grade or first-grade rich ore is firstly screened out, the magnesite tailings containing more than 46 percent of MgO are used for producing high-grade refractory materials, and the other magnesite tailings containing less than 46 percent of the second-grade and third-grade ores are thrown away as wastes at present, so that the great waste of resources is caused; the waste ores also contain 26-40% of MgO, and the MgO can be purified and utilized, which has great significance for saving resources, protecting resources and treating environmental pollution; simultaneously occupies land, pollutes environment, and does not accord with sustainable development strategy and the requirement of clean production process.
The light magnesium carbonate is produced by utilizing dolomite (CaO 30 percent and MgO 20 percent), and has the defects that: 1) the finished product of the light magnesium carbonate contains excessive CaO (more than 0.89), and the international standard is 0.43 percent; 2) a large amount of Ca and Mg mixture is discharged, which is not beneficial to environmental protection; 3) the process is complex, and Ca and Mg are not uniformly separated; 4) the cost is high, and Ca is extracted firstly and then Mg is extracted through two working procedures.
Disclosure of Invention
The invention aims to provide a method for producing light magnesium carbonate by utilizing magnesite tailings; the produced product has good quality, the CaO content of the finished product meets the international standard, the process is simple, and the cost is low.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for preparing light magnesium carbonate by utilizing magnesite tailings comprises the following specific processes:
1) and (3) calcining: smashing magnesite tailing ores, wherein the crushing granularity is 5-30 cm, and putting the smashed magnesite tailing ores into a lime kiln for calcining;
2) grinding: cooling the cooked magnesite clinker, taking out the cooled magnesite clinker from a furnace, primarily selecting, removing coal cinder, and grinding to 150-200 meshes;
3) digestion: putting the ground MgO powder into a digestion cylinder, adding water and materials, digesting the materials into a magnesium hydroxide emulsion, heating the feed liquid to 80 ℃, and preserving the heat for more than or equalto 1 hour;
4) c, carbon decomposition: pumping the magnesium hydroxide emulsion into a carbonization cylinder, adding water with the volume 7-8 times of that of the magnesium hydroxide emulsion, and mixing the digested magnesium hydroxide emulsion with CO2Performing carbonization reaction at a temperature of less than or equal to 30 ℃ and CO2A concentration of 27 to 30% and a gas pressure of 0.3 to 0.5MPa, wherein Mg (OH)2Forming the emulsion into a magnesium carbonate emulsion;
5) and (3) settling: putting the reacted magnesium carbonate emulsion into a sedimentation tank, settling, and filtering to obtain heavy magnesium water;
6) pyrolysis: pyrolyzing heavy magnesium water at 95-105 ℃, and forming small crystallized particles from light magnesium carbonate in the heavy magnesium water;
7) filtering and drying to obtain the finished product.
The lime kiln can be a vertical kiln, and the temperatures of the upper, middle and lower parts of the lime kiln are respectively as follows: 280-330 ℃, medium: 500-600 ℃, and the following steps: 260-340 ℃; content of magnesium ore (slaking rate): more than or equal to 80 percent; the temperature of the carbon decomposition cylinder is 20-30 ℃; the drying temperature is 150-230 ℃.
The invention has the following advantages:
1) the cost is low. The magnesite tailing waste containing less than 46 percent of MgO is used as the raw material, so that the waste is utilized, the resources are saved, and the production cost is low;
2) the process is simple. The material of the invention has low Ca content, does not need extraction, only uses one procedure, and saves energy; the production cost is reduced;
3) the product quality is good. The product produced by the invention has low Ca content, and the CaO content meets the international standard.
4) No pollution. The production process of the invention is pollution-free and meets the requirements of clean production process; and the problems that the raw material magnesite tailing waste occupies land and pollutes the environment are solved, so that the method has great significance for resource protection and environmental pollution treatment, and conforms to the strategy of sustainable development.
Detailed Description
At each step of production, a different chemical reaction takes place:
1. sintering magnesite: calcining MgCO3To become MgO
(ingredients) → digestion: hydration of MgO to Mg (OH)2
MgO+H2O→Mg(OH)2
3. Carbonization (carbonization): MgO and Mg (OH)2With CO2Reaction to produce liquid phase magnesium bicarbonate
MgO+2CO2+H2O→Mg(HCO3)2
Mg(OH)2+2CO2→Mg(HCO3)2
4. Pyrolysis: mg (HCO)3)2Heating to decompose and separate out precipitate
Examples
1) And (3) calcining: smashing magnesite tailing ores, wherein the granularity of the ores entering a kiln is as follows: 5-30 cm, placing the mixture into a lime kiln, calcining for about 2 hours, and dividing the temperature into an upper temperature, a middle temperature and a lower temperature in a vertical kiln, wherein the upper temperature is as follows: 280-330 ℃, medium: 500-600 ℃, and the following steps: 260-340 ℃; content of magnesium ore (slaking rate): more than or equal to 80 percent;
the weight ratio of the coal and the stone is as follows: 1 ton: 83-90kg (coal scalar 7000 kcal/kg);
discharging in the operation process: firstly, preparing a cooked material block and then adding materials; the feeding is that after the clinker is discharged, the ore (sand and stone are strictly forbidden to be mixed into the material to cause nodulation) and the coal are mixed and added, and the kiln cover is tightly closed to prevent air leakage after the material is charged;
the magnesite and coal are calcined in an ash kiln at high temperature to prepare carbon dioxide, the carbon dioxide is used as a raw material for producing light magnesium carbonate, and the concentration of the carbon dioxide is as follows: not less than 27-30%;
2) grinding: cooling the burnt magnesite clinker, taking out the magnesite clinker from the furnace, primarily selecting, removing coal slag, only remaining MgO, and grinding the magnesite clinker to 150-200 meshes by a Raymond machine;
3) digestion: adding water into 200kg of ground MgO powder for 3 tons, mixing, putting into a digestion tank, adding water and materials, digesting into a magnesium hydroxide emulsion (heating to 80 ℃ for 1 hour), and then cooling to below 30 ℃;
4) c, carbon decomposition: adding a certain amount of water into a cylinder to be carbonized, pumping the magnesium hydroxide emulsion into a carbonization cylinder, controlling the volume ratio of the magnesium hydroxide emulsion to the water to be 1: 7-8, and mixing the digested magnesium hydroxide emulsion with CO2Performing carbonization reaction (adjusting a cooling water valve, controlling the temperature to be less than or equal to 30 ℃, usually at 20-30 ℃) to ensure that Mg (OH)2Forming the emulsion into a magnesium carbonate emulsion;
by the gas of lime kiln output, the required pressure of carbonization process is stepped up to atmospheric gas through air compressor, air compressor machine exit pressure: (5 kg/cm)3)0.3～0.5MPa；
CO in this example2Gas concentration greater than 27% (total CO)2Concentration: 27-30%, header pressure: 0.4MPa), the gas pressure is 0.4MPa, and the PH value is 7; when CO is present2The gas difference between the main gas and the tail gas is less than or equal to 2 percent, the aeration and the stirring are stopped, and the carbonization is finished;
5) and (3) settling: and (3) putting the reacted magnesium carbonate emulsion into a settling tank, settling, filtering the precipitate by using a plate-and-frame filter (the filtering pressure is 0.2MPa) to remove impurities, wherein the filtered product is heavy magnesium water which is clear and transparent and has the concentration of more than 40%.
6) Pyrolysis: pyrolyzing the heavy magnesium water in a pyrolyzer at 95-105 ℃ (continuity), and forming small crystal particles from light magnesium carbonate in the heavy magnesium water. Pyrolysis rate: 95-98%; pyrolysis vapor pressure: 0.4 MPa;
7) plate-frame filtration: feeding the pyrolyzed feed liquid into a plate frame for filtering, and removing water to obtain a semi-finished product; the recovery rate of the semi-finished product is 98 percentthrough filtration; and (3) filtering pressure: 0.2 MPa;
8) and (3) drying: and (5) conveying the semi-finished product with high water content to a drying process to be dried into a qualified product and packaging. Controlling the moisture removal temperature to be 100-120 ℃, and controlling the water content of the product: less than or equal to 2 percent; the drying temperature is 150-230 ℃.
Claims (4)
1. A method for preparing light magnesium carbonate by utilizing magnesite tailings is characterized by comprising the following steps:
1) smashing magnesite tailing ores, wherein the crushing granularity is 5-30 cm, and putting the smashed magnesite tailing ores into a lime kiln for calcination;
2) cooling the cooked magnesite clinker, taking out the cooled magnesite clinker from a furnace, primarily selecting, removing coal cinder, and grinding to 150-200 meshes;
3) putting the ground MgO powder into a digestion cylinder, adding water and digesting the MgO powder into a magnesium hydroxide emulsion, heating the feed liquid to 80 ℃, and preserving the heat for more than or equal to 1 hour;
4) pumping the magnesium hydroxide emulsion into a carbonization cylinder, adding water with the volume 7-8 times of that of the magnesium hydroxide emulsion, and mixing the digested magnesium hydroxide emulsion with CO2Performing carbonization reaction at a temperature of less than or equal to 30 ℃ and CO2A concentration of 27 to 30% and a gas pressure of 0.3 to 0.5MPa, wherein Mg (OH)2Forming the emulsion into a magnesium carbonate emulsion;
5) putting the reacted magnesium carbonate emulsion into a sedimentation tank, settling, and filtering toobtain heavy magnesium water;
6) pyrolyzing heavy magnesium water at 95-105 ℃, and forming small crystallized particles from light magnesium carbonate in the heavy magnesium water;
7) filtering and drying to obtain the finished product.
2. The method for preparing light magnesium carbonate by using magnesite tailings as claimed in claim 1, wherein the method comprises the following steps: the lime kiln is a vertical kiln, and the temperatures of the upper, middle and lower parts of the lime kiln are respectively as follows: 240-400 ℃, medium: 500-800 ℃, and the following steps: 260-340 ℃; content of the magnesite: more than or equal to 80 percent.
3. The method for preparing light magnesium carbonate by using magnesite tailings as claimed in claim 1, wherein the method comprises the following steps: the temperature in the carbon decomposition cylinder is 20-30 ℃.
4. The method for preparing light magnesium carbonate by using magnesite tailings as claimed in claim 1, wherein the method comprises the following steps: the drying temperature is 150-230 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004101004044A CN100368295C (en) | 2004-12-17 | 2004-12-17 | Method for producing light magnesium carbonate by utilizing magnesite tailings |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004101004044A CN100368295C (en) | 2004-12-17 | 2004-12-17 | Method for producing light magnesium carbonate by utilizing magnesite tailings |
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| CN1789133A CN1789133A (en) | 2006-06-21 |
| CN100368295C true CN100368295C (en) | 2008-02-13 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103143433A (en) * | 2013-03-06 | 2013-06-12 | 瓮福（集团）有限责任公司 | Method for combined processing of phosphogypsum and phosphate reverse flotation tailings |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103172093B (en) * | 2013-03-06 | 2014-12-17 | 云南磷化集团有限公司 | Phosphogypsum processing method |
| CN103626211A (en) * | 2013-12-04 | 2014-03-12 | 沈阳化工大学 | Method for preparing heavy magnesium carbonate through heavy magnesium water |
| CN103910365B (en) * | 2014-04-18 | 2015-12-09 | 武汉工程大学 | A kind of method utilizing phosphate reverse flotation de-magging mine tailing to prepare light magnesium oxide |
| WO2018139975A1 (en) * | 2017-01-25 | 2018-08-02 | Nanyang Technological University | Enhanced reactive magnesia cement-based concrete mixes |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1495300A1 (en) * | 1987-06-02 | 1989-07-23 | Предприятие П/Я А-3732 | Method of producing magnesium bicarbonate solution |
| CN1150123A (en) * | 1996-09-20 | 1997-05-21 | 张得新 | Production of magnesium carbonate by carbonizing process of magnesite |
| CN1408666A (en) * | 2001-09-29 | 2003-04-09 | 沈阳市苏家屯区胜利砂轮厂 | process for producing magnesium oxide from waste magnesite ore |
-
2004
- 2004-12-17 CN CNB2004101004044A patent/CN100368295C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU1495300A1 (en) * | 1987-06-02 | 1989-07-23 | Предприятие П/Я А-3732 | Method of producing magnesium bicarbonate solution |
| CN1150123A (en) * | 1996-09-20 | 1997-05-21 | 张得新 | Production of magnesium carbonate by carbonizing process of magnesite |
| CN1408666A (en) * | 2001-09-29 | 2003-04-09 | 沈阳市苏家屯区胜利砂轮厂 | process for producing magnesium oxide from waste magnesite ore |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103143433A (en) * | 2013-03-06 | 2013-06-12 | 瓮福（集团）有限责任公司 | Method for combined processing of phosphogypsum and phosphate reverse flotation tailings |
| CN103143433B (en) * | 2013-03-06 | 2014-08-20 | 瓮福（集团）有限责任公司 | Method for combined processing of phosphogypsum and phosphate reverse flotation tailings |
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| CN1789133A (en) | 2006-06-21 |
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Granted publication date: 20080213 Termination date: 20131217 |