CN1018850B - Method for making cathod carbon block used in aluminium electrolytic bath - Google Patents
Method for making cathod carbon block used in aluminium electrolytic bathInfo
- Publication number
- CN1018850B CN1018850B CN 91100789 CN91100789A CN1018850B CN 1018850 B CN1018850 B CN 1018850B CN 91100789 CN91100789 CN 91100789 CN 91100789 A CN91100789 A CN 91100789A CN 1018850 B CN1018850 B CN 1018850B
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- China
- Prior art keywords
- semi
- graphited
- aluminium electrolytic
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- temperature
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
The present invention relates to a preparation method for cathode carbon blocks for aluminium electrolytic cells. Calcined anthracite, metallurgical coke, a little ash coke and graphite chips (or phosphorus sheet graphite) are used as aggregates, and asphalt is used as adhesives. After materials are formed by pugging, the temperature of a calcination furnace is increased for 280 to 360 hours and is kept at 1100 to 1300 DEG C (an optimum value is from 1250 to 1350 DEG C). Then, the formed materials are heated by electricity to 1800 to 2300 DEG C (an optimum value is from 1900 to 2150 DEG C) in a resistance furnace and are semi-graphitized, and finally, finished products in a needed shape are built.
Description
The present invention relates to the manufacture method of cathod carbon block used in aluminium electrolytic bath, particularly resistivity is low, the manufacture method of the semi-graphited cathode carbon pieces that electrolyte-resistant solution etch performance is good.
As everyone knows, the cathode portion of aluminium cell constitutes with carbonaceous material with aluminium liquid and ionogen contact site.Particularly bottom of electrolytic tank all is to constitute with the charcoal piece.In the electrolysis operation process, this charcoal piece Chang Yin is subjected to thermal stresses and chemical etching effect and damages and cause shut-down, and in addition, in the electrolysis operation, the volts lost of cathode carbon pieces also can influence the energy consumption of electrolysis process.For this reason, require cathode carbon pieces to have good resistance to compression, tensile strength, resistance to sudden heating, electrolyte-resistant solution etch performance and electroconductibility and wear resistance.
The cathode carbon pieces that the aluminum current electrolyzer uses has common anthracite-base cathode carbon pieces, semi-graphite cathode carbon block, semi-graphited cathode carbon pieces and graphitized cathode carbon block etc. several.
Common anthracite-base cathode carbon pieces is that to use the hard coal after 1250～1350 ℃ of calcinings be aggregate, is binding agent with the coal-tar pitch, behind kneading and compacting, forms through 1300 ℃ of left and right sides roastings again.The carbon back that constitutes it originally belongs to amorphous carbon, the aluminium electrolytic cell cathode of building by laying bricks or stones with this charcoal piece, in aluminium electrolysis process, be subjected to sodium ion etch rate of expansion big (linear expansivity reaches 1.5%), physical strength greatly reduces after the etch, so work-ing life is short, in addition, its resistivity is bigger, is generally (50～60) * 10
-6Ω m, thereby the electric tank cathode pressure drop that is built into this charcoal piece is big, the power consumption height.
Semi-graphite cathode carbon block is that using through 1700～2000 ℃ of electric forge furnace incinerating hard coals is orthopaedics, with pitch be binding agent behind kneading and compacting, form through 1300 ℃ of roastings again.Hard coal in this charcoal piece is because electric forge furnace radial temperature difference is bigger, and its aggregate performance fluctuation is bigger, has only part to reach semi-graphited, the coke of binder pitch formation also belongs to amorphous carbon in addition, therefore, the resistivity of this charcoal piece is still bigger, is generally (40～45) * 10
-6Ω m, electrolytic expansivity are 0.8～1.2%.Ultimate compression strength is low to be 9Mpa, so the electric tank cathode pressure drop of building by laying bricks or stones with this charcoal piece is still higher, during expanded by heating, arch upward in the bottom, and easily generation is ruptured, and work-ing life is also shorter.
Graphitized cathode carbon block, owing to will adopt burnt manufacturing of the few ash of high-quality, its raw material sources are restricted and cost an arm and a leg, course of processing energy consumption height, the manufacturing process difficulty is big, thereby is difficult to apply.
With regard to present circumstances, the raw materials used source of semi-graphited charcoal piece is wide, low price, and charcoal piece resistivity is low, potential resistance to electrolyte contamination etch performance is good, and can satisfy electrolyzer and maximize and requirements of saving energy, be aluminium electrolytic cell cathode ideal replacement material.
At present, domestic semi-graphited cathode carbon pieces adopts the used method manufacturing of Hefei aluminium manufacturer, be about to common anthracite-base cathode carbon pieces and put into the Graphite Electrodes napex of graphitizing furnace, waste heat when utilizing graphitized electrode in the graphitizing furnace, after making the charcoal piece realize the high temperature semi-graphited, form through processing to build by laying bricks or stones at last.The charcoal piece of making in this way, because hard coal becomes shortcake and becomes fragile after pyroprocessing, thereby its tension, ultimate compression strength all very low (ultimate compression strength has only about 10Mpa), in addition, because the charcoal piece is placed in the Graphite Electrodes top layer insulation material, upper and lower temperature difference is bigger, causes the performance difference of charcoal piece top and the bottom bigger, and whole charcoal piece physical and chemical performance uniformity coefficient is poor.
The objective of the invention is to overcome the deficiencies in the prior art, a kind of raw material that the source is wide, price is low that adopts is provided, produce that resistivity is low, the potential resistance to electrolyte contamination erosion is good, the suitable method of making cathod carbon block used in aluminium electrolytic bath of physical and chemical performance homogeneous.
The manufacture method of cathod carbon block used in aluminium electrolytic bath of the present invention comprises batching and kneading and compacting, roasting and semi-graphited three-procedure.
Raw materials usedly be: the hard coal after 1250～1300 ℃ of calcinings, metallurgical coke, few grey Jiao and graphite broken (or crystalline flake graphite), binding agent is a pitch.Each proportion of raw materials (weight percentage) is respectively 40～50,0～30, and 0～35,0～10 and 15～25, the granularity (mm) of raw material (except that pitch) is distributed as: ± 12:＜2% ,-12～+ 4; 25 ± 4% ,-0.5:40 ± 4% ,-0.075:29 ± 3%.
With above-mentioned raw materials through routine mix pinch after, with extruding or vibratory compaction, usually making the cross section is that 420mm * 420mm length is the piece of predetermined length, then in stoving oven, heated up through 280～360 hours and insulation to 1100～1380 ℃ (optimum value is 1250～1350 ℃), according to circumstances can in circular furnace or ground kiln or down-draft kiln, carry out with condition, roasting.Subsequently whole immigration of the charcoal piece after the roasting carried out the semi-graphited processing in the resistance furnace, semi-graphited is everlasting and is carried out in Acheson's resistance furnace, its processing condition are: 2000～3000 kilowatt-hours of energising amounts, 30～45 hours conduction time, temperature is controlled at 1800～2300 ℃ (optimum value is 1900～2150 ℃) in the stove, makes the graphite state before the charcoal piece reaches complete greying.At last product processing is built into by laying bricks or stones the finished product of required cathode shape.
Cathode carbon pieces with method manufacturing of the present invention has following advantage and effect:
Wide, the low price of raw material sources, be easy to apply;
2. product performance obviously are better than common anthracite-base cathode carbon pieces and semi-graphite cathode carbon block, Jiao who burns till because of its feed particles and pitch, all reach semi-graphited, so performance is even, the intensity height, good toughness, its main performance index is: greying index＞0.8, ash＜7%, resistivity 3 * 10
-6Ω m, ultimate compression strength＞17Mpa, true density＞2.06g/cm
2, volume density 1.52g/cm
3, electrolytic expansivity 0.5%.
The aluminium electrolytic cell cathode of building by laying bricks or stones with the semi-graphited charcoal piece of method manufacturing of the present invention is low because of the rate of expansion that produced by the sodium ion etch in electrolytic process, therefore reduce fracture because of upwards arching upward and produced, so can prolong the work-ing life of cathode carbon pieces, simultaneously owing to having reduced the volts lost of negative electrode, so reduced the power consumption in the electrolytic process.
The embodiment of cathod carbon block used in aluminium electrolytic bath manufacture method of the present invention lists in table 1, and the physical and chemical performance of product is shown in table 2.
The manufacturing process of table 1 cathode carbon pieces
Sequence number 12345
No proportioning (%) 46 ± 2 46 ± 2 46 ± 2 48 ± 2 47 ± 2
Cigarette
Coal blending granularity (mm) 12-0 12-0 12-0 12-0 12-0
Smelting proportioning (%) 16 ± 2 13 ± 2
Gold
Expect burnt granularity (mm) 0.5-0 0.5-0
Few proportioning (%) 18 ± 2 17 ± 2 26 ± 2 32 ± 2 29 ± 2
Ash
Burnt granularity (mm) 0.5-0 of worker 0.5-0 0.5-0 0.5-0 0.5-0
Stone proportioning (%) 4 ± 18 ± 24 ± 1
China ink
Preface particle degree (mm) 0.5-0 0.5-0 0.5-1
Pitch proportioning (%) 20 ± 2 20 ± 2 20 ± 2 20 ± 2 20 ± 2
Oven type circular furnace ground kiln down-draft kiln circular furnace circular furnace
Burn
Worker's temperature (℃) 1250 ± 25 1350 ± 25 1300 ± 25 1250 ± 25 1250 ± 25
Preface
Time (hour) 360 280 360 324 320
Half temperature (℃) 2050 ± 50 2150 ± 50 2150 ± 55 2050 ± 50 2150 ± 50
Stone
Black conduction time (hour) 36 38 35 37 40
Change
Worker's energising measures 2,500 3,000 3,000 2,500 2600
Preface (kilowatt-hour)
The physical and chemical performance of table 2 cathode carbon pieces
Sequence number 12345
Greying index 0.8 0.8 0.82 0.80 0.80
Porosity (%) 26.42 25.95 26.31 26.23 26.49
Resistivity (10 Ω m) 23-28 21-45 18-23 22-26 20-25
Ultimate compression strength (MPa) 20-23 20-25 21-23 21.3 20.8
Volume density (g/cm) 1.55 1.56 1.57 1.56 1.55
Bending strength (MPa) 10-12 10-12 11 9.7 10.3
True density (g/cm) 2.12 2.14 2.14 2.12 2.12
The swollen rate that rises of electrolysis (%) 0.44 0.42 0.40 0.45 0.47
Ash (%) 6.06 3.96 3.87 4.22 4.30
Claims (3)
1, a kind of manufacture method of cathod carbon block used in aluminium electrolytic bath comprises batching and kneading and compacting, and roasting and semi-graphited operation is characterized in that:
A) raw material and proportioning (weight percentage): the hard coal 45～50 after 1250～1300 ℃ of calcinings, metallurgical coke 0～30, few ash Jiao 0～35, broken (or the crystalline flake graphite) 0～10 of graphite, pitch 15～25;
B) raw material (except that pitch) granularity (mm) distributes :+12:＜2% ,-12～+ 4: 25 ± 4%;-0.5: 40 ± 4%;-0.075: 29 ± 3%;
C) sinter process condition; Intensification and soaking time 280～360 hours, 1100～1380 ℃ of top temperatures;
D) semi-graphited processing condition: 30～45 hours conduction time, 2000～3000 kilowatt-hours of energising amounts, 1800～2300 ℃ of temperature.
2, method according to claim 1 is characterized in that roasting at circular furnace, carries out in ground kiln or the down-draft kiln.
3, method according to claim 1, the temperature that it is characterized in that calcining process is 1250～1350 ℃, the temperature of semi-graphited operation is 1900～2150 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91100789 CN1018850B (en) | 1991-02-09 | 1991-02-09 | Method for making cathod carbon block used in aluminium electrolytic bath |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 91100789 CN1018850B (en) | 1991-02-09 | 1991-02-09 | Method for making cathod carbon block used in aluminium electrolytic bath |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1055016A CN1055016A (en) | 1991-10-02 |
| CN1018850B true CN1018850B (en) | 1992-10-28 |
Family
ID=4904818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 91100789 Expired CN1018850B (en) | 1991-02-09 | 1991-02-09 | Method for making cathod carbon block used in aluminium electrolytic bath |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1018850B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101306949B (en) * | 2008-01-31 | 2011-05-11 | 四川启明星铝业有限责任公司 | Charcoal blocks with semi- graphitic side part for electrolyzing aluminium and production process thereof |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103374730A (en) * | 2012-04-28 | 2013-10-30 | 夏华松 | Wettable cathode cylinder with crystal graphite as plastid and production method thereof |
| CN102924103A (en) * | 2012-11-22 | 2013-02-13 | 四川广汉士达炭素股份有限公司 | Carbon brick, and production method and application of carbon brick |
| CN105420758A (en) * | 2015-12-01 | 2016-03-23 | 宁夏宁平炭素有限责任公司 | Preparing method for whole-coal carbon block cathodes |
-
1991
- 1991-02-09 CN CN 91100789 patent/CN1018850B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101306949B (en) * | 2008-01-31 | 2011-05-11 | 四川启明星铝业有限责任公司 | Charcoal blocks with semi- graphitic side part for electrolyzing aluminium and production process thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1055016A (en) | 1991-10-02 |
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