CN109942210B - Method for preparing high-activity magnesium oxide from magnesite - Google Patents
Method for preparing high-activity magnesium oxide from magnesite Download PDFInfo
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- CN109942210B CN109942210B CN201910417958.3A CN201910417958A CN109942210B CN 109942210 B CN109942210 B CN 109942210B CN 201910417958 A CN201910417958 A CN 201910417958A CN 109942210 B CN109942210 B CN 109942210B
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Abstract
The invention provides a method for preparing high-activity magnesium oxide from magnesite, which comprises the following steps: crushing, grinding, twice roasting, magnetic separation and the like. The invention adopts neutralityReduction two-stage roasting process, both of which are roasting at lower temperature, ensuring that under the condition of low-temperature roasting magnesite is decomposed to generate MgO amorphous body, the magnesite is firstly roasted under neutral condition to complete partial decomposition, and MgCO is used3The generated CO is used for the back-stage roasting, the generated CO is used as reducing gas to reduce weak magnetic iron minerals in the magnesite into strong magnetic iron minerals, the weak magnetic iron minerals are removed through magnetic separation, the undecomposed magnesite is continuously decomposed in the reducing roasting process, the magnesite is completely decomposed finally through the two-stage roasting under the low-temperature condition, MgO crystals are prevented from being rapidly generated under the high-temperature condition, MgO amorphous substances in the obtained active magnesium oxide are more in component and higher in activity, and the citric acid detection CAA value of the active magnesium oxide is 13-15 s.
Description
Technical Field
The invention relates to the technical field of magnesite calcination, in particular to a method for preparing high-activity magnesium oxide from magnesite.
Background
The magnesite resources in China are abundant, the proven reserves are about 31 hundred million t and account for one fourth of the total reserves in the world, the magnesite resources are mainly distributed in Liaoning provinces and Shandong provinces, the total reserves account for about 95.11% of the total reserves in the country, the Liaoning province is mainly concentrated in the south areas of Liaoning provinces, such as the sea city, the Yingkou and other areas, the proven mine areas are 12, the reserved reserves are 25.77 million t and account for about 85% of the total reserves in the country and account for 20% of the total reserves in the world. The existing calcination methods for magnesium oxide include fixed bed type (such as tunnel kiln, down-draft kiln, shuttle kiln, pushed slab kiln and heat-insulating cylinder), semi-fixed bed type (such as vertical kiln, rotary kiln and multi-layer open hearth), fluidized bed type (laboratory stage), etc. The method for preparing light-burned magnesia by calcining magnesite in a shaft kiln is a commonly adopted method, but when the kiln is used for calcining magnesia, raw materials used must have certain granularity, and a large amount of powdery materials are generated in the processes of raw material mining and ore crushing, so that a large amount of powdery magnesite is wasted.
The active magnesium oxide is an important raw material for preparing high-function fine inorganic materials, electronic elements, printing ink and harmful gas adsorbents. Is expected to be developed into a tip material under severe conditions of high temperature, high corrosion and the like. It can also be used as filler for paint, paper and cosmetics, filler and reinforcing agent for plastics and rubber, and auxiliary material for various electronic materials.
At present, activated magnesium oxide is calcined by adopting lump ore magnesite mostly at 800-1000 ℃, so that the phenomenon of overburning or underburning is easily caused, the number of air holes in the fired material is small, the density is large, the size of magnesium oxide grains is large, and the activity is obviously reduced. In addition, the magnesite is often accompanied with that impurities such as ferric oxide, ferrous oxide and the like are not removed, the quality of active magnesium oxide is affected, and the activity of the active magnesium oxide is also reduced.
Disclosure of Invention
The invention aims to provide a method for preparing high-activity magnesium oxide from magnesite so as to solve the problems in the background technology.
The technical scheme of the invention is realized as follows:
a method for preparing high-activity magnesium oxide from magnesite comprises the following steps:
(1) crushing and grinding magnesite to-0.074 mm which accounts for more than 80 percent of the total weight to obtain magnesite powder;
(2) putting magnesite powder in a suspension roasting furnace, introducing air to enable the magnesite powder to be in a suspension state, roasting in a neutral roasting chamber of the suspension roasting furnace to obtain a neutral roasting material, and collecting gas generated by roasting;
(3) conveying the neutral roasted material to a reduction roasting chamber of a suspension roasting furnace, and introducing the gas collected in the step (2) for roasting to obtain a reduction roasted material;
(4) and carrying out dry magnetic separation on the reduced roasting material to remove iron impurities, thereby obtaining the active magnesium oxide.
Preferably, the neutral roasting temperature in the step (2) is 630-700 ℃, and the roasting time is 8-10 min.
Preferably, the gas collected in step (2) contains CO and C as main components2O, wherein the CO is generated by incomplete decomposition of magnesite in a neutral roasting process.
Preferably, the reduction roasting temperature in the step (3) is 450-500 ℃, and the roasting time is 5-8 min.
Preferably, the magnetic field intensity of the dry magnetic separation in the step (4) is 800-1000 Oe.
The invention has the beneficial effects that:
the invention adopts two stages of neutral-reductionThe two sections of the roasting process are both roasted at lower temperature, so that the magnesite is decomposed to generate MgO amorphous body under the condition of low-temperature roasting, the magnesite is firstly roasted under the neutral condition to complete partial decomposition, and MgCO is partially decomposed3The generated CO is used for the back-stage roasting, the generated CO is used as reducing gas to reduce weak magnetic iron minerals in the magnesite into strong magnetic iron minerals, the weak magnetic iron minerals are removed through magnetic separation, the undecomposed magnesite is continuously decomposed in the reducing roasting process, the magnesite is completely decomposed finally through the two-stage roasting under the low-temperature condition, MgO crystals are prevented from being rapidly generated under the high-temperature condition, MgO amorphous substances in the obtained active magnesium oxide are more in component and higher in activity, and the citric acid detection CAA value of the active magnesium oxide is 13-15 s.
Detailed Description
The technical solution of the present invention will be described in detail and fully with reference to the following examples, and it should be understood that the described examples are only a part of the examples of the present invention, and not all of the examples. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The magnesium oxide content of Liaoning magnesite is 45.48%, and the TFe content is 2.05%.
Example 1
A method for preparing high-activity magnesium oxide from magnesite comprises the following steps:
(1) crushing and grinding magnesite to 80 percent of-0.074 mm in total weight to obtain magnesite powder;
(2) putting magnesite powder in a suspension roasting furnace, introducing air to enable the magnesite powder to be in a suspension state, roasting in a neutral roasting chamber of the suspension roasting furnace at the roasting temperature of 630 ℃ for 10min to obtain a neutral roasting material, and collecting gas generated by roasting;
(3) conveying the neutral roasted material to a reduction roasting chamber of a suspension roasting furnace, introducing the gas collected in the step (2) for roasting, wherein the roasting temperature is 470 ℃, and the roasting time is 6min to obtain a reduction roasted material;
(4) and carrying out dry magnetic separation on the reduced roasting material to remove iron impurities, wherein the magnetic field intensity is 1000Oe, and obtaining the active magnesium oxide.
The magnesite obtained according to this example has a magnesia content of 98.2% and a TFe content of 0.22%. The CAA value of the citric acid detection is 15 s.
Example 2
A method for preparing high-activity magnesium oxide from magnesite comprises the following steps:
(1) crushing and grinding magnesite to 85 percent of-0.074 mm in total weight to obtain magnesite powder;
(2) putting magnesite powder into a suspension roasting furnace, introducing air to enable the magnesite powder to be in a suspension state, roasting in a neutral roasting chamber of the suspension roasting furnace at 670 ℃ for 9min to obtain a neutral roasting material, and collecting gas generated by roasting;
(3) conveying the neutral roasted material to a reduction roasting chamber of a suspension roasting furnace, introducing the gas collected in the step (2) for roasting, wherein the roasting temperature is 450 ℃, and the roasting time is 8min to obtain a reduction roasted material;
(4) and carrying out dry magnetic separation on the reduced roasting material to remove iron impurities, wherein the magnetic field intensity is 900Oe, and obtaining the active magnesium oxide.
The magnesite obtained according to this example has a magnesia content of 98.8% and a TFe content of 0.20%. The CAA value of the citric acid detection is 14 s.
Example 3
A method for preparing high-activity magnesium oxide from magnesite comprises the following steps:
(1) crushing and grinding magnesite to 90 percent of-0.074 mm in total weight to obtain magnesite powder;
(2) putting magnesite powder into a suspension roasting furnace, introducing air to enable the magnesite powder to be in a suspension state, roasting in a neutral roasting chamber of the suspension roasting furnace at 700 ℃ for 8min to obtain a neutral roasting material, and collecting gas generated by roasting;
(3) conveying the neutral roasted material to a reduction roasting chamber of a suspension roasting furnace, and introducing the gas collected in the step (2) for roasting at the roasting temperature of 500 ℃ for 5min to obtain a reduction roasted material;
(4) and carrying out dry magnetic separation on the reduced roasting material to remove iron impurities, wherein the magnetic field intensity is 800Oe, and obtaining the active magnesium oxide.
The magnesite obtained according to this example has a magnesia content of 99.2% and a TFe content of 0.18%. The CAA value of the citric acid detection is 3 s.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (3)
1. A method for preparing high-activity magnesium oxide from magnesite comprises the following steps:
(1) crushing and grinding magnesite to-0.074 mm which accounts for more than 80 percent of the total weight to obtain magnesite powder;
(2) putting magnesite powder in a suspension roasting furnace, introducing air to enable the magnesite powder to be in a suspension state, roasting in a neutral roasting chamber of the suspension roasting furnace to obtain a neutral roasting material, and collecting gas generated by roasting, wherein the neutral roasting temperature is 630-700 ℃, and the roasting time is 8-10 min;
(3) conveying the neutral roasted material into a reduction roasting chamber of a suspension roasting furnace, and introducing the gas collected in the step (2) for roasting to obtain a reduction roasted material, wherein the reduction roasting temperature is 450-500 ℃, and the roasting time is 5-8 min;
(4) and carrying out dry magnetic separation on the reduced roasting material to remove iron impurities, thereby obtaining the active magnesium oxide.
2. The method for preparing high-activity magnesium oxide from magnesite according to claim 1, wherein the gas collected in the step (2) mainly comprises CO and C2O, wherein the CO is generated by incomplete decomposition of magnesite in a neutral roasting process.
3. The method for preparing high-activity magnesium oxide from magnesite according to claim 1, wherein the magnetic field strength of the dry magnetic separation in the step (4) is 800-1000 Oe.
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| CN112551921B (en) * | 2020-11-25 | 2022-06-07 | 海城远东矿业有限公司 | Carbonization activation beneficiation technology for high-silicon magnesite |
| CN113772970B (en) * | 2021-09-01 | 2022-09-30 | 鞍钢集团北京研究院有限公司 | Method for preparing magnesium oxide by using magnesite |
| CN114350940A (en) * | 2021-12-25 | 2022-04-15 | 深圳市考拉生态科技有限公司 | Method for producing alkaline iron ore concentrate by reducing weakly magnetic iron ore |
| CN115572080B (en) * | 2022-11-09 | 2024-01-16 | 营口菱镁化工集团有限公司 | Preparation method of feed-grade magnesium oxide |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106082289A (en) * | 2016-06-21 | 2016-11-09 | 太仓市东明化工有限公司 | A kind of preparation method of extra light calcined magnesia |
| CN108504855A (en) * | 2018-05-09 | 2018-09-07 | 东北大学 | A method of producing iron ore concentrate by reducing agent suspending magnetization roasting of siderite |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106082289A (en) * | 2016-06-21 | 2016-11-09 | 太仓市东明化工有限公司 | A kind of preparation method of extra light calcined magnesia |
| CN108504855A (en) * | 2018-05-09 | 2018-09-07 | 东北大学 | A method of producing iron ore concentrate by reducing agent suspending magnetization roasting of siderite |
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