CN100338243C - Aluminothermic reduction method and technology of giobertite calcination to produce magnesium - Google Patents
Aluminothermic reduction method and technology of giobertite calcination to produce magnesium Download PDFInfo
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- CN100338243C CN100338243C CNB2005100470811A CN200510047081A CN100338243C CN 100338243 C CN100338243 C CN 100338243C CN B2005100470811 A CNB2005100470811 A CN B2005100470811A CN 200510047081 A CN200510047081 A CN 200510047081A CN 100338243 C CN100338243 C CN 100338243C
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- magnesium
- magnesite
- reduction method
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Abstract
The present invention relates to an aluminothermic reduction method for calcining magnesite to produce magnesium, which provides a new reaction formula. The aluminothermic reduction method uses magnesite powder as a raw material and aluminium powder as a reducing agent. The present invention is characterized in that (1), 5 to 15 wt% of calcination limestone powder (CaO) is used as an auxiliary agent; (2), the magnesite powder is calcined at the temperature of 700 to 1000 DEG C for 1 hour to produce active MgO; (3), the magnesite powder, the limestone powder and the aluminum powder are pressed into lumps under the pressure intensity of 40 to 450MPa after 35 to 80 portions of magnesite powder, 5 to 15 portions of limestone powder and 15 to 54 portions of aluminum powder are uniformly mixed according to the proportion by weight; (4), the lumps are put in a reaction tank, the lumps reaction tank is pumped into vacuum of 1 to 13.3 Pa, the lumps are put in a reduction furnace to be heated, and then an obtained mixture is reduced at the temperature of 1050 to 1170 DEG C for 4 to 8 hours to produce crude magnesium. The present invention also provides an optimum parameter in the aluminothermic reduction method. Compared with the traditional Pidgeon method and the known aluminothermic magnesium producing technology, the aluminothermic reduction method lowers energy consumption, enhances yield, saves raw materials and reduces the treating capacity of waste slag. In a word, the aluminothermic reduction method has the advantages of high popularization value and high social and economic benefits.
Description
Technical field
The invention belongs to technical field, promptly relate to a kind of processing method of aluminothermy for smelting Mg with the extraction of aluminium reducing metal and magnesium.
Background technology
At present, the production method of magnesium is divided into two big classes, magnesium chloride fused salt electrolysis process and hot reducing method, and the electrolytic process energy consumption is excessive, and environmental pollution is serious, lessly is that the people adopts.And most widely used in the hot reducing method be Pidgeon process, promptly so that to calcine back rhombspar (MgOCaO) be raw material and be reductive agent with ferrosilicon (Si-Fe), under the vacuum condition of 1200 ℃ and 1.3～13.3Pa, react the generation MAGNESIUM METAL.Yet also there is following shortcoming in Pidgeon process: reduction temperature height, thereby energy consumption higher (～13 tons of coal/ton magnesium); Reduction cycle long (12 hours), production efficiency is low; Single jar of magnesium output lower (～30Kg/ time), day output is low; Slag amount is big (～7 tons of slag/ton magnesium), and slag is worth low.
The technology that Chinese patent ZL93115701.3 discloses a kind of " is the aluminothermy for smelting Mg of raw material with magnesite and rhombspar ", adopt aluminium powder, magnesium oxychloride and rhombspar by 1～2: 2～4: 6～15 scale material, earlier with magnesite, dolomite calcination behind abrasive dust, with granularity be that 80～100 purpose aluminium powder batch mixings depress to agglomerate at the pressure of 15～35 MPas, put into metal trough and send into the reduction jar again, generate MAGNESIUM METAL through reaction in 6～8 hours under 1100～1170 ℃ of vacuum conditions, its chemical equation is prosperous the putting forward of Wu Xian in 1991:
21MgO+12CaO+14Al=21Mg+12CaO7Al
2O
3(1) its material magnesium ratio reaches 3.72; Slag magnesium ratio is 2.72; Than the following reaction formula that Zhang Riqiang proposed in 1981:
9MgO+5CaO+6Al=9Mg+5CaO3Al
2O
3(2) material magnesium than 3.68 and slag magnesium all higher than 2.68.And at calcined dolomite MgCO
3CaCO
3The time, because CaCO
3Decomposition need be warming up to 1200 ℃, and under this temperature, MgCO
3Its activity of MgO of decomposing has shown acute decline, the effect that had not obtained so calcined dolomite system magnesium had both consumed energy, and some is lost more than gain actually.
Summary of the invention
The present invention is directed to the problem that present thermal reduction legal system magnesium technology exists, seek a kind of new system magnesium processing method to realize reducing the thermal reduction temperature with energy-conservation; Shorten reduction cycle, improve the magnesium recovery rate, further improve magnesium output; Reduce material magnesium ratio and slag magnesium ratio, targets such as conservation and minimizing quantity of slag quantity discharged.
Through contriver's research, thermite process reduction-oxidation magnesium refines magnesium, and can write with its chemical reaction general formula of CaO auxiliary agent becomes:
Analyze from reaction formula, the effect of CaO only is and Al
2O
3In conjunction with forming stable compound, reaction is accomplished.On the other hand, from CaO-Al
2O
3Draw in the research of binary system phase diagram: have four kinds of stable compounds, they are: CaOAl
2O
3(can be abbreviated as CA); CaO2Al
2O
3(CA
2); 3CaOAl
2O
3(C
3A) and CaO6Al
2O
3(CA
6).And 12CaO7Al
2O
3(C
12A
7) only be a kind of metastable phase, it is not a binary compound, C
12A
7Aerial fusing point is 1392 ℃, is being decomposed into CA+G below 1360 ℃
3The A eutectic.Equally, C
5A
3Also be unsettled.Its same C
12A
7The composition difference is very little, and many research cement think that with concrete scholar they are with a kind of mutually unstable.So the contriver thinks that the theoretical foundation of thermite process should not be above-mentioned two chemical equation, and should be following four kinds of reaction formula.Now that they are as follows than arranging from low to high by material magnesium:
(1) generates CaO6Al
2O
3(CA
6)
18MgO+CaO+12Al＝18Mg+CaO·6Al
2O
3 (3)
(2) generate CaO2Al
2O
3(CA
2)
6MgO+CaO+4Al＝6Mg+CaO·2Al
2O
3 (4)
(3) generate CaOAl
2O
3(CA)
3MgO+CaO+2Al＝3Mg+CaO·Al
2O
3 (5)
(4) generate 3CaOAl
2O
3(C
3A)
3MgO+3CaO+2Al＝3Mg+3CaO·Al
2O
3 (6)
In four kinds of chemical equation of following formula, the material magnesium of first three kind than and slag magnesium lower than equal more currently used Wus, a reaction formula that is proposed, economic benefit is also better.
Design of the present invention is just from the achievement of above-mentioned research work, promptly just is that with the difference of disclosed technical scheme the method applied in the present invention is is theoretical basis with reaction formula (3), (4), (5).
Thermite reduction calcined magnesite magnesium refining method proposed by the invention is characterized in that adopting following three chemical equation to carry out:
18MgO+CaO+12Al＝18Mg+CaO·6Al
2O
3
6MgO+CaO+4Al＝6Mg+CaO·2Al
2O
3
3MgO+CaO+2Al＝3Mg+CaO·Al
2O
3
The invention allows for a kind of technology of implementing thermite reduction calcined magnesite magnesium refining method, adopting the magnesite breeze is that raw material, aluminium powder are reductive agent, and the limestone powder after the calcining is made auxiliary agent, and its processing step is as follows:
(1) the magnesite breeze that will be milled to 0.25～0.075mm granularity becomes active MgO at 700～1000 ℃ of temperature lower calcinations;
(2) limestone powder and the aluminium powder after the magnesite breeze after will calcining, the calcining is 35～65.64: 5～15 by weight: be pressed into agglomerate behind 29.28～54 mixings under 40～450 MPa pressure;
(3) agglomerate that suppresses is put into retort, be evacuated to 1～13.3Pa and place reduction furnace to heat, under 1050～1170 ℃ of conditions, react and made crude magnesium in 4～8 hours.
Technology of the present invention, the calcining temperature optimum value of magnesite is 900 ℃, the average activity degree that burn till MgO this moment is up to 30.58%.This is than adopting rhombspar (MgCO
3CaCO
3) calcining temperature is 1200～1250 ℃ and will hangs down 1/4 when making raw material, energy-saving effect is obvious.And adopting white clouds masonry raw material, its material magnesium ratio and slag magnesium are higher than all, because wherein contain CaCO
3Surpass MgCO
31.19 doubly.
The optimum material proportion of technology of the present invention percentage ratio by weight is calculated as MgO: CaO: Al=65.64: 5.07: 29.28.
Its optimum value of pressure of compacting agglomerate is 300 MPas in the technology of the present invention.
Optimal reaction temperature is 1150 ℃ in the processing method of the present invention, and optimum reacting time is 6 hours.
The advantage and the positively effect of processing method of the present invention are as follows:
(1) and Pidgeon process compare: reduction temperature is low 50 ℃, and the recovery time has shortened 40%; Magnesium output has improved 50%, and the rate of recovery of magnesium has improved 14.42%; And material magnesium ratio has reduced by 69.85%, conservation; Slag magnesium ratio has reduced by 75.28%, has reduced the treatment capacity of waste residue, helps environmental protection.
(2) and disclosed thermite process compare, the present invention is owing to adopt magnesite breeze and limestone powder to calcine respectively, the magnesite breeze can be obtained optimum activity 900 ℃ of temperature calcinings, need not to heat to 1200 ℃, only need limestone powder separately 1100 ℃ of calcinings down, this can also improve the activity of MgO than not only saving the energy at 1200～1250 ℃ of temperature lower calcination rhombspars, can be rated as and kills two birds with one stone.And owing to adopted more rational condition and new more rational chemical equation, make material magnesium than further being reduced to 2.53 from 3.72, promptly reduced by 32%; Slag magnesium has promptly reduced by 44% than being reduced to 1.53 from 2.72, and benefit is also fairly obvious.
Description of drawings
Fig. 1 is the FB(flow block) of the processing method of production of magnesium by pidgeonprocess;
Fig. 2 is the FB(flow block) of processing method of the present invention;
Embodiment
Below in conjunction with embodiment content of the present invention is further described and replenishes.
Embodiment 1
Raw material is handled:
Earlier with magnesite (MgCO
3) be broken to granularity 0.25mm powder through coarse crushing, middle flour after, made active MgO, fine grinding sieving for standby again in 1 hour 700 ℃ of calcinings; Again with same technology with Wingdale (CaCO
3) be ground into granularity be behind the 0.833mm powder 1100 ℃ down calcining made CaO powder, fine grinding sieving for standby again in 1 hour.
The batching briquetting:
MgO after calcining sieved and CaO fine powder and aluminium powder be percentage ratio by weight: 80: 5: 15 uniform mixing, the pressure with 40 MPas is pressed into agglomerate under pressing machine again.
Reduction system magnesium:
The agglomerate that presses is placed in the retort of Pidgeon process, again retort is sent in the process furnace (being reduction furnace), be evacuated to 1 handkerchief post-heating to 1050 ℃, reacted 8 hours, promptly make crude magnesium.
Embodiment 2
Raw material is handled:
Earlier magnesite is broken to granularity 0.075mm through first broken, middle flour, makes active MgO, sieving for standby after the fine grinding after 1 hour 1000 ℃ of calcinings; Again Wingdale is pulverized back calcining under 1100 ℃ with same process and made the CaO powder that granularity is 0.075mm in 1 hour, the back of sieving is standby.
The batching briquetting:
MgO after calcining sieved and CaO fine powder and aluminium powder be 35: 15: 54 uniform mixing of percentage ratio by weight, and the pressure with 450 MPas is pressed into agglomerate under pressing machine again.
Reduction system magnesium:
The agglomerate that presses is placed in the retort of Pidgeon process, retort is sent in the process furnace again, be evacuated to 13.3 handkerchiefs and heat, be incubated 4 hours down at 1170 ℃, reduction obtains crude magnesium.
Embodiment 3
Raw material is handled:
Active MgO after just broken, middle flour is broken to granularity 0.15mm powder, 900 ℃ of calcinings 1 hour, is made, fine grinding sieving for standby again with magnesite by elder generation; Made CaO, sieving for standby after the fine grinding in 1 hour 1150 ℃ of following calcinings after with same process limestone powder being broken into the powder that granularity is 0.25mm again.
The batching briquetting:
MgO after calcining sieved and CaO powder and aluminium powder be 65.64: 5.07: 29.28 uniform mixing of percentage ratio by weight, and the pressure with 300 MPas is pressed into agglomerate under pressing machine again.
Reduction system magnesium:
The agglomerate that presses is placed in the retort of Pidgeon process, again retort is sent in the reduction furnace, be evacuated to 2 handkerchiefs, reacted 6 hours down, promptly make crude magnesium at 1150 ℃.
In a word, because the present invention finds and has proposed the new chemical equation of aluminium reducing calcined magnesite system magnesium, that is:
18MgO+CaO+12Al＝18Mg+CaO·6Al
2O
3 (3)
6MgO+CaO+4Al＝6Mg+CaO·2Al
2O
3 (4)
3MgO+CaO+2Al＝3Mg+CaO·Al
2O
3 (5)
Reduced material magnesium ratio and slag magnesium ratio significantly, this had both saved raw material, had reduced the treatment capacity of waste residue again.And energy consumption had then both been saved in the calcining respectively under differing temps with magnesite breeze and limestone powder, had guaranteed the high reactivity of MgO again, had further shortened reduction cycle, had improved magnesium output.
Claims (1)
1, a kind of method of thermite reduction giobertite calcination magnesium, it is characterized in that adopting the magnesite breeze is raw material, and aluminium powder is a reductive agent, and the limestone powder after the calcining is made auxiliary agent, and its processing step is as follows:
(1) the magnesite breeze that will be milled to 0.25～0.075mm granularity becomes active MgO at 700～1000 ℃ of temperature lower calcinations;
(2) limestone powder and the aluminium powder after the magnesite breeze after will calcining, the calcining is 35～65.64: 5～15 by weight: be pressed into agglomerate behind 29.28～54 mixings under 40～450 MPa pressure;
(3) agglomerate that suppresses is put into retort, be evacuated to 1～13.3Pa and place reduction furnace to heat, under 1050～1170 ℃ of conditions, react and made crude magnesium in 4～8 hours.
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|---|---|---|---|
| CNB2005100470811A CN100338243C (en) | 2005-08-24 | 2005-08-24 | Aluminothermic reduction method and technology of giobertite calcination to produce magnesium |
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|---|---|---|---|
| CNB2005100470811A CN100338243C (en) | 2005-08-24 | 2005-08-24 | Aluminothermic reduction method and technology of giobertite calcination to produce magnesium |
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|---|---|
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| CN100338243C true CN100338243C (en) | 2007-09-19 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011127672A1 (en) * | 2010-04-12 | 2011-10-20 | 东北大学 | Method for producing metallic magnesium by vacuum reduction |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100463717C (en) * | 2007-06-26 | 2009-02-25 | 南京云海特种金属股份有限公司 | Catalyzer used in pidgeon's magnesium reduction process and the magnesium reduction process adopting the catalyzer |
| CN101798634B (en) * | 2010-04-13 | 2011-11-09 | 重庆大学 | Process for smelting magnesium through melting reduction |
| CN103374665A (en) * | 2012-04-27 | 2013-10-30 | 昊青薪材（北京）技术有限公司 | Technology for preparing magnesium metal by magnesium oxide aluminothermic reduction method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2017844C1 (en) * | 1990-05-22 | 1994-08-15 | Акционерное общество открытого типа "Всероссийский алюминиево-магниевый институт" | Method of magnesium producing from its oxide |
| CN1098143A (en) * | 1993-07-28 | 1995-02-01 | 东北大学 | With magnesite and rhombspar is the aluminothermy for smelting Mg of raw material |
| CN1584076A (en) * | 2004-06-04 | 2005-02-23 | 郭清富 | Method for preparing magnesium with silica-alumina alloy as electronating agent |
-
2005
- 2005-08-24 CN CNB2005100470811A patent/CN100338243C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2017844C1 (en) * | 1990-05-22 | 1994-08-15 | Акционерное общество открытого типа "Всероссийский алюминиево-магниевый институт" | Method of magnesium producing from its oxide |
| CN1098143A (en) * | 1993-07-28 | 1995-02-01 | 东北大学 | With magnesite and rhombspar is the aluminothermy for smelting Mg of raw material |
| CN1584076A (en) * | 2004-06-04 | 2005-02-23 | 郭清富 | Method for preparing magnesium with silica-alumina alloy as electronating agent |
Non-Patent Citations (1)
| Title |
|---|
| 以菱镁矿为原料的铝热法炼镁试验研究 郭清富，轻金属，第1期 1997 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011127672A1 (en) * | 2010-04-12 | 2011-10-20 | 东北大学 | Method for producing metallic magnesium by vacuum reduction |
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| CN1730685A (en) | 2006-02-08 |
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