A kind of electrolytic aluminium carbon anode antioxidizing paint
Technical field
It is specific or one the present invention relates to the technology that carbon anode high-temperature oxydation is prevented during a kind of Aluminum Electrolysis Production
Kind electrolytic aluminium carbon anode high-temp antioxidizing paint.
Background technology
Aluminium is a kind of metallic element that reserves are very big in the earth's crust, distributed pole is wide, 7.5% is accounted in the earth's crust, than other
The summation of all non-ferrous metals is more.Early in 1854, french chemist Deville mixed bauxite, charcoal, salt, leads to
Heating has obtained double salt after entering chlorine, then this double salt and excessive sodium fusion are melted, and has obtained metallic aluminium.1886, the person of outstanding talent in the U.S.
You are the Hai Langte with France, and separately metallic aluminium has been made in the mixture of electrolyzing fused bauxite and ice crystal, for the present
Its large-scale production aluminium is laid a good foundation.Due to the rapid development of power-generating industry, modern aluminum industry production is essentially all using ice
Spar-aluminium oxide molten salt electrolysis.Wherein molten cryolitic is solvent, and aluminium oxide is as solute, using carbon body as anode,
After being passed through powerful direct current, at 950 DEG C~970 DEG C, it is electrochemically reacted, that is, is electrolysed on the two poles of the earth in electrolytic cell.
Anodic oxidation product is mainly carbon dioxide and CO gas, wherein containing pernicious gases such as a certain amount of hydrogen fluoride and admittedly
Body dust.Purified treatment need to be carried out to anodic gas, be discharged into after removing pernicious gas and dust for environmental protection and human health
Air.Cathode product is molten aluminum, and molten aluminum is extracted out by vacuum ladle out of slot, is sent to foundry, purified in holding furnace
After clarification, high-purity aluminium ingot is cast into, is used for foundary industry.
Various metals or nonmetalloid are added in fine aluminium, the aluminium alloy of casting can be configured to, its casting character
It is more excellent with performance ratio fine aluminium.Since it has above-mentioned many advantages, industrially have been widely used.Mesh
Before, it is industrial that aluminium alloy is not only widely used in military affairs, space flight, aviation, light industry, heavy industry and communications and transportation etc., moreover, also extensively
For building structural materials, family life apparatus and sports goods etc..
100 for many years, although there are a variety of aluminium metallurgy new methods, including improved chlorination aluminium reduction process, oxidation
Aluminium carbon heat reducing method, vulcanization aluminium reduction process etc., but all there is no commercial Application.Have ice crystal-alumina molten salt electrolysis only
The application of method is lasting, is still industrial unique metallurgy method for aluminum so far.
In the aluminium electrolysis process using ice crystal-alumina molten salt electrolysis method, anode is the main original of aluminum electrolysis
One of material carries the important component of important role and aluminum electrolysis cost in aluminum electrolysis.In electricity
It solves in aluminium production process, carbon anode consumption includes electrochemistry consumption, chemical depletion and machinery consumption etc..Due to anode carbon block master
Ingredient is wanted to be susceptible to anodic oxidation phenomenon, wherein carbon anode and CO for charcoal2And O2Change caused by the oxidation reaction of generation
The main reason that consumption is anode excessive consumption is learned, is consumed only so as to add anode, increases aluminum electrolysis cost.Press mesh
The Hall Heroult process that preceding aluminium electrolytic industry uses, the oxygen that using carbon anode electrolysis of aluminum oxide when releases at high temperature
Anodic oxidation consumes.Charcoal amount 333kg will be consumed by theoretically often producing one ton of aluminium, and the charcoal amount of aluminium manufacturer's actual consumption is 500
~600kg, accounts for 15% of totle drilling cost or so.Therefore, for each electrolysis aluminum production enterprises, one ton of aluminium of production is consumed
Charcoal amount be one and need the important indicator examined, so, improve the anti-aging capability of carbon anode at high temperature, reduce electrolysis
The consumption of carbon anode, has caused the highest attention of people and has carried out extensive experiment in aluminium production.
In order to reduce the high-temperature oxydation consumption of the excessive carbon anode caused by the burning of oxygen in air, electricity is reduced
The production cost of aluminium is solved, both economical effective method is that protective coating is applied on the surface of carbon anode, is reduced
The high-temperature oxydation loss of carbon anode caused by air, it is many both at home and abroad so far so as to extend the service life of carbon anode
Scholar has been presented for the patent of various anti-oxidation electrode compounds.
Meanwhile at this stage manufacturer in order to prevent during Aluminum Electrolysis Production carbon anode high-temperature oxydation, use
The broken material of electrolysis al molten bath slag is covered in the carbon anode surface do not immersed inside electrolyte, as isolated protective layer, purport
Contact of the carbon anode with oxygen in air is being prevented, so as to achieve the purpose that the high-temperature oxydation scaling loss for preventing carbon anode.But
It is that the coating of this solid slag broken material is more loose, it is impossible to ensure the complete isolation of carbon anode and air completely.And
Containing substantial amounts of cryolite in this slag, it is a kind of very strong material of corrosivity, particularly at high temperature, except charcoal with
It outer various metals and nonmetallic can be corroded.For traditional carbon anode high-temp antioxidizing barrier coating, some into
This is higher, and some need layered coating can be only achieved contact of the isolation carbon anode with air, cannot particularly slag be prevented to cover
The heat erosion caused by it of the fluorine element of cryolite in cap rock, frequently can lead to high-temp antioxidizing barrier coat be corroded and
It loses it and completely cuts off the shielding action of air.
In short, the anode isolated protective layer being successfully applied at present in aluminum electrolysis production technique, is imitated suitable for production application
Fruit does not have preferably substantially.It searches to the bottom reason, although its oxidation proof properties having are preferable, liquid electrolyte or fine aluminium
Some impurity are introduced in water and polluted the purity of fine aluminium;And have although to reach oxidation proof propertiess preferable, anti-fluorine from
The corrosive power of son is poor, because ice crystal is a kind of highly corrosive agents, coating is corroded and nothing left of trickling at high temperature, loses too early
Protective effect.Therefore, a kind of electrolytic aluminium carbon anode protective coating of excellent combination property is developed, there is larger economic effect
Benefit and social benefit.
The content of the invention
The object of the present invention is to provide a kind of electrolytic aluminium carbon anode antioxidizing paints.
To achieve the above object, the technical solution adopted by the present invention is:
A kind of electrolytic aluminium carbon anode antioxidizing paint, coating by weight percentage, alumina powder 30-40%, fluorine
Change sodium 10-20%, aluminum fluoride 10-20%, composite antioxidant 1.0-5.0%, binding agent 10-25%, suspending agent 2-5% and remaining
It measures as solvent;The composite antioxidant is metallic aluminium powder and boride;The binding agent is waterglass;The suspending agent is sodium
Base bentonite or attapulgite;The solvent is water.
Granularity≤10 μm of the alumina powder, granularity≤45 μm of sodium fluoride, granularity≤45 μm of aluminum fluoride, metallic aluminium
Granularity≤5 μm of powder, granularity≤10 μm of boride.Wherein, in alumina powder, sodium fluoride, aluminum fluoride, metallic aluminium and boride
Objectionable impurities (Si, Fe, Ti, Cr, Mn and K etc.) total content should≤5.0%, preferably≤1.0%.
Further, the coating is by weight percentage:Alumina powder 30%, sodium fluoride 10%, aluminum fluoride 10%,
Metallic aluminium powder 1.0%, boride 3.0%, waterglass 20%, sodium bentonite 4% and water 22%.
Or, the coating is by weight percentage:Alumina powder 32%, sodium fluoride 12%, aluminum fluoride 10%, metallic aluminium powder
0.8%th, boride 3.5%, waterglass 20%, sodium bentonite 3% and water 18.7%.
Or, the coating is by weight percentage:Alumina powder 35%, aluminum fluoride 13%, sodium fluoride 10%, metallic aluminium powder
0.5%th, boride 4.0%, waterglass 22%, sodium bentonite 2% and water 13.5%.
Or, the coating is by weight percentage:Alumina powder 35%, sodium fluoride 11%, aluminum fluoride 10%, metallic aluminium powder
0.8%th, boride 2.5%, waterglass 20%, sodium bentonite 3% and water 17.7%.
Advantage for present invention:
The electrolytic aluminium carbon anode of the present invention is with high-temp antioxidizing paint mainly by filler, composite antioxidant, bonding
The multiphase suspension system of the high degree of dispersion of the Multiple components such as agent, suspending agent and solvent composition.Aluminium oxide, aluminum fluoride in filler and
The materials such as sodium fluoride form the sintered body of composite diphase material after high temperature sintering, and the high temperature with fluorine in stronger anti-ice spar is rotten
The ability of erosion.Although there is preferable oxidation-protective effect to charcoal containing boron material, boron need to be strictly controlled in antioxidizing paint
Content, it is otherwise very unfavorable to the corrosivity and inoxidizability of the ice crystal in high temperature aluminum-resistant electrolyte and anti-oxidation at present
The price containing boron material and its addition used in material is generally higher, therefore the present invention is proposed using metallic aluminium powder and boron
The composite antioxidant of compound composition substitutes single boride antioxidant.
It can be seen that the carbon anode high-temp antioxidizing paint of the present invention, can improve the anti-oxidation energy of carbon anode at high temperature
Power and prevent fluorine corrosiveness of the ice crystal slag to coating, so as to effectively reduce the consumption of carbon anode in Aluminum Electrolysis Production,
Extend the service life of carbon anode, save anode consuming cost, reduce the discharge capacity of toxic gas, hence it is evident that improve operation ring
Border achieves preferable economic benefit and social benefit.
Description of the drawings
Fig. 1 is carbon annode test block protective coating high-temperature oxydation burn-out test figure.
Specific embodiment
Embodiment 1
Electrolytic aluminium carbon anode high-temp antioxidizing paint, by weight percentage, alumina powder 30%, sodium fluoride
10%th, aluminum fluoride 10%, metallic aluminium powder 1.0%, boride 3.0%, waterglass 20%, sodium bentonite 4% and water 22% are mixed
It closes and is configured to.
Embodiment 2
Electrolytic aluminium carbon anode high-temp antioxidizing paint, by weight percentage, alumina powder 32%, sodium fluoride
12%th, aluminum fluoride 10%, metallic aluminium powder 0.8%, boride 3.5%, waterglass 20%, sodium bentonite 3% and water 18.7%
It is hybridly prepared into.
Embodiment 3
Electrolytic aluminium carbon anode high-temp antioxidizing paint, by weight percentage, alumina powder 35%, aluminum fluoride
13%th, sodium fluoride 10%, metallic aluminium powder 0.5%, boride 4.0%, waterglass 22%, attapulgite 2% and water 13.5% are mixed
Conjunction is configured to.
Embodiment 4
Electrolytic aluminium carbon anode high-temp antioxidizing paint, by weight percentage, alumina powder 35, sodium fluoride 11%,
Aluminum fluoride 10%, metallic aluminium powder 0.8%, boride 2.5%, 17.7% mixed preparing of waterglass 20%, attapulgite 3% and water
Into.
Electrolytic aluminium carbon anode is tested with high-temp antioxidizing paint in high temperature furnace obtained by above-described embodiment, is tried
It is as follows to test result:
A certain size carbon electrode test block is produced, the coating of different compositions, thickness 0.5mm are respectively applied on its surface
Left and right.Then, through spontaneously dry 24 it is small when or in an oven 100 DEG C drying 2 it is small when after, be put into high-temperature electric resistance furnace and be warming up to stove
1000 DEG C (heating rates be 200 DEG C/h), when heat preservation 10 is small after take out, be cooled to the oxygen that specimen surface is observed after room temperature
Change scaling loss situation.Result of the test is found, has brushed the carbon electrode test block surface coating densification of the antioxidizing paint in embodiment
Completely, carbon electrode test block protection is good (1# in such as Fig. 1), has achieved the purpose that protect carbon anode high temperature scaling loss.And it applies
The surface of the carbon electrode test block of other types coating is applied, all there are the phenomenon that different degrees of carbon graphite oxidization burning loss.
Wherein:
1# is 1 gained ingredient coating of the embodiment of the present invention;
2# paint ingredients:Waterglass 22%, boride 8.0%, alumina powder 30%, sodium fluoride 12%, aluminum fluoride 10%,
Sodium bentonite 3% and water surplus.
3# paint ingredients:Waterglass 18%, boride 13%, alumina powder 32%, boehmite 9.5%, sodium base are swollen
Profit soil 3% and water surplus.
By the metallic aluminium in above-mentioned visible electrolytic aluminium carbon anode high-temp antioxidizing paint of the present invention and boride in height
It first can be with O under temperature2Or CO reactions generate aluminium oxide and boron oxide, then its reaction product is further reacted with refractory oxide
Generate aluminium borate.For the aluminium borate generated at high temperature in glassy state stream material, it can preferably fill complex phase sintering
Hole in body forms the higher antioxidant coating protective film of compactness.During particularly aluminium is reacted with CO into carbon, i.e. Al
→Al4C3→Al2O3, meeting is with certain volume expansion, so that paint structure is more densified, it at high temperature can be effective
Prevention oxygen is contacted directly with carbon anode surface, achievees the purpose that protect carbon annode oxidization burning loss.
In addition, by the electrolytic aluminium carbon anode high-temp antioxidizing paint of above-mentioned acquisition on certain aluminium manufacturer's electrolytic aluminium carbon annode
Application test is carried out, application method is as follows:First by advance finely dispersed antioxidizing paint brushing or it is sprayed on carbon
The upper surface and side of anode, after being evenly coated with one to twice, spontaneously dry at normal temperatures 12 it is small when more than it is for use.Using knot
Fruit shows:The carbon anode of unused this coating finds that anode surface oxidization burning loss is serious after pulling out pole cleaning, and corner angle almost do not have
Having, even there is arrisdefect, de- pole phenomenon in some, and with above-mentioned formula with high-temp antioxidizing paint brushing obtained in carbon anode
The anode surface in electrolyte molten bath is not immersed, by the application of a cycle (30 days or so), is found after pulling out pole cleaning, it is remaining
Carbon anode corner angle are clearly demarcated, and remaining carbon anode highly significantly increases.Therefore every piece of anode extension can be reached and use one
It effect, so that the production cost of aluminium per ton declines 80 yuan.The medium-sized aluminium manufacturer for producing 500000 tons of aluminum amount per year for one, every year
40,000,000 yuan of cost can directly be saved.