OA17185A - Electrolyte used for aluminum electrolysis and electrolysis process using the electrolyte. - Google Patents
Electrolyte used for aluminum electrolysis and electrolysis process using the electrolyte. Download PDFInfo
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- OA17185A OA17185A OA1201400538 OA17185A OA 17185 A OA17185 A OA 17185A OA 1201400538 OA1201400538 OA 1201400538 OA 17185 A OA17185 A OA 17185A
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- electrolyte
- naf
- electrolysis
- température
- aif
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- 239000003792 electrolyte Substances 0.000 title claims abstract description 115
- 238000005868 electrolysis reaction Methods 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 74
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 19
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 17
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Inorganic materials [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims abstract description 72
- 235000013024 sodium fluoride Nutrition 0.000 claims abstract description 72
- KLZUFWVZNOTSEM-UHFFFAOYSA-K AlF3 Chemical compound F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 claims abstract description 53
- PNEYBMLMFCGWSK-UHFFFAOYSA-N AI2O3 Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 51
- 229910052593 corundum Inorganic materials 0.000 claims abstract description 4
- 229910001845 yogo sapphire Inorganic materials 0.000 claims abstract description 4
- 239000000155 melt Substances 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 19
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Inorganic materials [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 abstract description 9
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 3
- 239000000470 constituent Substances 0.000 abstract 2
- 238000002425 crystallisation Methods 0.000 abstract 1
- 230000005712 crystallization Effects 0.000 abstract 1
- 150000004673 fluoride salts Chemical class 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 14
- 238000005260 corrosion Methods 0.000 description 9
- KRHYYFGTRYWZRS-UHFFFAOYSA-M fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 9
- 101710011445 BHLH147 Proteins 0.000 description 8
- REHXRBDMVPYGJX-UHFFFAOYSA-H Sodium hexafluoroaluminate Chemical compound [Na+].[Na+].[Na+].F[Al-3](F)(F)(F)(F)F REHXRBDMVPYGJX-UHFFFAOYSA-H 0.000 description 4
- 229910001610 cryolite Inorganic materials 0.000 description 4
- WUKWITHWXAAZEY-UHFFFAOYSA-L Calcium fluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 3
- ORUIBWPALBXDOA-UHFFFAOYSA-L Magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 3
- 229910001634 calcium fluoride Inorganic materials 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000009776 industrial production Methods 0.000 description 3
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- OYLGJCQECKOTOL-UHFFFAOYSA-L Barium fluoride Chemical compound [F-].[F-].[Ba+2] OYLGJCQECKOTOL-UHFFFAOYSA-L 0.000 description 2
- 229910001632 barium fluoride Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- 101710043140 GTF2A1L Proteins 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N HCl Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 235000014787 Vitis vinifera Nutrition 0.000 description 1
- 240000006365 Vitis vinifera Species 0.000 description 1
- -1 aluminum Ions Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000002035 prolonged Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
Abstract
The present invention relates to an electrolyte used for aluminum electrolysis and an electrolysis process using the electrolyte. The electrolyte of the present invention employs a pure fluoride salt system and consists of the following mass percent of constituents: 20% to 29.9% of NaF, 60.1% to 66% of A1F3, 3% to 10% of LiF, 4% to 13.9% of KF, and 3% to 6% of Al2O3, where the molar ratio of NaF to AlF3 is between 0.6 and 0.995; or consists of the following mass percent of constituents: 30% to 38% of NaF, 49% to 60% of AlF3, 1% to 5% of LiF, 1% to 6% of KF, and 3% to 6% of A12O3, where the molar ratio of NaF to AlF3 is between 1.0 and 1.52. The electrolyte provided in the present invention is provided with a reduced primary crystallization temperature and improved solubility of aluminum oxide, while the electrolyte is provided with an increased electric conductivity. The electrolyte of the present invention provides improved effects of reduced energy consumption, increased current efficiency, and improved working environment during the electrolysis process.
Description
Description
ELECTROLYTE FOR ALUMINUM ELECTROLYSIS AND ELECTROLYSIS PROCESS USING ELECTROLYTE
Fleld of the Invention
The présent Invention relates to an electrolyte for alumlnum electrolysis and an electrolysis process using the electrolyte, belonging to non-ferrous métal smelting Industry.
Backg round of the Invention
Aluminum electrolysis refers to acquisition of alumlnum by means of an electrolysis method. In the prior art, a traditional Hall-Heroult molten sait alumlnum electrolysis process Is typically adopted for aluminum electrolysis. This process Is featured by use of a cryolite-alumina molten sait electrolysis method In which cryolite NajAIFe fluoride sait melt Is taken as flux, AI2O3 is dissolved in fluoride sait, carbon body is taken as an anode, aluminum liquid is taken as a cathode, and electrolytic aluminum is obtained by performing electrochemical reaction at the anode and cathode of the electrolytic cell at a high température ranging from 940 to 960*C after a strong direct current is introduced. Due to high electrolysis température, the traditional alumlnum electrolysis process has such characteristics as large volatilization amount of electrolyte, large oxldization loss of a carbon anode, large energy consumption, large thermal loss and poor electrolysis working environment.
In the prior art, In order to lower electrolysis température, a low température molten sait system for alumlnum electrolysis Is described In Chinese patent document CN101671835A, the molten sait composition of the system includes AIF3, AI2O3 and one or more salts selected from the group consisting of KF, NaF, MgF2, CaF2, NaCI, LIF, and BaF2, wherein according to moie percentage, the content of AIF3 Is 22-50%, the content of AI2O3is 1-25% and the content of the rest components is 25-77%. The electrolysis température of the electrolyte can be lowered to be within a wide area from 680*C to 900’C for the purpose of operations. In the aforementioned electrolyte, however, BaF2 Is liable to sédimentation In the electrolysis process due to large density, so It Is hardly applied to Industrial production In an extensive fashion; use of MgF2 and CaF2, which are hlgh-melting-polnt substances, will increase the liquidus température of the entire System and will also dégradé the eiectric conductivity and the alumlna solubility of the eiectrolyte; because NaCI has a relatively low melting point, addition of NaCI Is a way of lowering the liquidus température of the eiectrolyte, however, NaCI Imposes a corrosion effect on such metals as Cu, Fe, Al and Ni at the aforementioned electrolysis température and will further lead to corrosion of métal parts like electrolytic cell accessorles, thls corrosion effect dramatlcally shortens the service life of electrolysis devices, furthermore, NaCI Is extremely liable to volatillzation In the electrolysis process so as to form HCl gas that Is harmful to human body, so until now, NaCI has not been wldely applied to Industrial production; In addition to addition of NaCI, decrease of the molar ratio of NaF to AIF3 can also lower the liquidus température of the eiectrolyte in light of common knowledge in this art, but in the existing industry, the molar ratio of NaF to AlFs Is generally larger than 2.2, this is because an unsolvable problem will arise if the liquidus température of the eiectrolyte Is further lowered and the electrolysis température Is lowered correspondingly, namely, NaF and AIF3 will lead to a 'crusting' phenomenon of the cathode in the process of low-temperature electrolysis, the reason for this 'crusting* phenomenon Is that sodium ions and alumlnum Ions In the eiectrolyte will gather at the cathode in the electrolysis process to generate sodium cryolite, which is seldom molten at a low température due to Its high melting point, as a resuit, the surface of the cathode is covered by a layer of refractory cryolite crust to affect normal electrolysis in the electrolysis process tremendously.
Whether an eiectrolyte can be successfully applied to industrial production Is based on comprehensive considération for many factors like its liquidus température, volatility, eiectric conductivity, alumlna solubility, préparation environment and whether stable electrolysis process can be guaranteed, however, due to the above problems in the prior art, Industrial application of the eiectrolyte is significantly limited, and It is an unsolved problem in the prior art to find a way of avolding corrosion to electrolysis devices and damage to human body and ensuring proper eiectric conductivity and alumlna solubility as well as no ‘crusting’ phenomenon of the prepared eiectrolyte whlle the liquidus température of the eiectrolyte Is further lowered.
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Summary ofthe Invention
The technical problem to be solved by the présent invention is that, the prior art is incapable of avoiding corrosion to electrolysis devices and damage to human body and ensuring proper electric conductivity and alumina solubility as well as no ’crusting’ phenomenon of the prepared electrolyte while the liquidus température of the electrolyte is further lowered. Thus the présent Invention provides an electrolyte for aluminum electrolysis, which is low In liquidus température, free from corrosion to an electrolytic cell, not liable to volatilizatlon, proper In electric conductivity and alumina solubility and free from ‘crustlng’ phenomenon, and an electrolysis process using the electrolyte.
The technical solution for the electrolyte for aluminum electrolysls and the electrolysls process using the electrolyte in the présent Invention is as follows:
An electrolyte foraluminum electrolysls Is composed ofthe following components by mass percent: 20-29.9% of NaF, 60.1-66% of AIF3, 3-10% of UF, 4-13.9% of KF and 3-6% of AI2O3, wherein the molar ratio of NaF to AIF3 is 0.6-0.995;
or composed of the following components by mass percent: 30-38% of NaF, 49-60% of AIF3,1-5% of UF, 1-6% of KF and 3-6% of Al2O3, wherein the molar ratio of NaF to AIF3 Is 1,0-1.52.
The molar ratio of NaF toAIF3 Is 0.6-0.7 or 1.12-1.52.
The liquidus température of the electrolyte ranges from 620 to 670eC.
The liquidus température of the electrolyte ranges from 640 to 670*C.
The electrolysis température of the electrolyte ranges from 720 to 760’C.
An electrolysls process using the electrolyte for aluminum electrolysis comprises the steps of:
(1) mixing specified amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant mixture to form a melt; or mixing specified amounts of NaF, AIF31 UF and KF, heating the résultant mixture until the mixture is molten, and then adding AI2O3to obtaln a melt; and (2) heating up the melt prepared in step (1) to 720-760eC and then carrying out electrolysls.
The melt prepared In step (1) Is electrolyzed at 730-750’C.
AI2O3 is quantitatively supplied in the eiectrolysis process.
The electrolyte for aluminum eiectrolysis and the eiectrolysis process using the electrolyte in the présent invention hâve the advantages below:
(1) The electroiyte for aluminum eiectrolysis in the présent invention employs a pure fluoride system and Is composed of the following components by mass percent: 20-29.9% of NaF, 60.1-66% of AIF3, 3-10% of LJF, 4-13.9% of KF and 3-6% of AI2O3, wherein the moiar ratio of NaF to AiF3 is 0.6-0.995; or the electrolyte Is composed of the following components by mass percent: 30-38% of NaF, 49-60% of AiF3,1-5% of UF, 1-6% of KF and 3-6% of AI2O3, wherein the molar ratio of NaF to AIF3 is 1.0-1.52.
The advantages resulted from this are as follows:
1. Low liquidus température and no 'crusting' phenomenon. In the Invention, an electrolyte with a pure fluoride system Is employed, substance composition in the electrolyte Is defined, the contents of these substances are further defined and the molar ratio of NaF to AIF3ls 0.6-0.995 or 1.0-1.52, so that the liquidus température of the electroiyte is iowered to 640-670’C, as a resuit, eiectrolysis can be carried out at 720-760’C according to the eiectrolysis process, which reduces voiatiiizatlon loss of fluoride sait, avoids corrosion to eiectrolysis device and damage to human body, improves working environment, greatiy reduces energy consumption In the eiectrolysis process and achieves the alms of energy saving and émission réduction; and meanwhile, in the présent invention, proper amounts of LJF and KF are added and can be combined with sodium ions and aluminum Ions in the electrolyte to form lithium cryolite and potassium cryoiite with low melting points, thus ensuring no crusting phenomenon in the eiectrolysis process.
2. High aiumina solubility. Compared with the existing industry, the electrolyte for aluminum eiectrolysis In the présent invention has no CaF2 and MgF2 added therein, instead, KF In an appropriate proportion, which has the function of increasing aiumina solubility and dissolution veiocity, Is added to a system In which the moiar ratio of NaF to AiF3 is 0.6-0.995 or 1.0-1.52, and therefore, the shortcoming of low aiumina solubility in the low-molar-ratio electrolyte is Improved.
3. High electric conductivity of the electrolyte. The electric conductivity of the electrolyte decreases as the température decreases, so typically, the electric conductivity at a low electrolysls température hardly me et s the demand In a normal electrolysis process; the electrolysls température Is lowered by lowering the Iiquidus température of the electrolyte In the présent Invention, however, the electric conductivity of the electrolyte at a low température can still meet the demand In the electrolysis 5 process because LIF with a iarger electric conductivity Is added and component proportions In the electrolyte are optimized, thus enhanclng the current efficiency In the electrolysis process. According to the Invention, the content of UF Is defined as 3-10% or 1-5% in the electrolyte System, this Is because too low content of UF fails to improve electric conductivity and to prevent crusting, and too high content of LiF results in decrease of the alumlna solubility, and the above two situations are 10 effectively avoided by defining the content of LiF In the présent invention.
4. Réduction of métal corrosion. There Is no corrosion to an electrolytic cell device when the electrolyte with the above proportions is used, so that the service life of the electrolytic cell device is prolonged.
(2) In the electrolysis process of the présent Invention, spedfied amounts of NaF, AIF3, UF, KF and 15 AkOjare mlxed, the résultant mixture Is heated to form a melt; or specified amounts of NaF, AIF3,
UF and KF are mlxed, the résultant mixture is heated until the mixture is molten, and then AI2O3ls added to obtain a melt; afterwards, the melt prepared is etectroiyzed at 720*C-760eC. Electrolysis température is directly associated with votatilization of the electrolyte, energy consumption of the process, electric conductivity and alumlna solubility, and the inventor of the présent invention, by 20 long research, set the electrolysis température within a range from 720’C to 760*C in a matching way based on the components and content characteristics of the electrolyte In the présent Invention, thus volatilization of the electrolyte and energy consumption in the electrolysis process are remarkably reduced while both the electric conductivity and the alumina solubility are increased, and the économie efficiency of the process Is Improved.
Preferably. the electrolysis température is further set within a range from 730 to 750*C In the présent Invention.
For more easily understanding the technical solution of the présent invention, further description will be made below to the technical solution of the présent Invention in conjunction with the embodiments.
Detalled Description of the Embodiments
Embodiment 1
The components of the electrolyte In this embodiment are as follows: 20% of NaF, 65.98% of AIF3, 5.01% of LiF, 6.01% of KF and 3% of AI2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3 is 0.6.
The performances of the electrolyte in thls embodiment are measured and the measurement resuit Is that the liquidus température ofthe electrolyte in this embodiment is 640*C.
The electrolysis process using the electrolyte In thls embodiment Is as follows:
(1) mixing the aforementioned amounts of NaF, AIF3, LiF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared In step (1) to 720’C and then carrying out electrolysis, and quantitatively supplying Ai2O3in the electrolysis process, wherein In the electrolysis process, the electric conductivity of the electrolyte Is about UQ^cm'1, the density Is about 2.03g/cm3 and the saturation concentration of alumlna is 5%.
Embodiment 2
The components of the electrolyte in this embodiment are as follows: 29.9% of NaF, 60.1% of AIF3, 20 3% of LIF, 4% of KF and 3% of AI2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3 Is
0.995.
The performances of the electrolyte in this embodiment are measured and the measurement resuit isthatthe liquidus température oftheelectrolyte In thls embodimentIs 670* C.
The electrolysis process using the electrolyte in this embodiment Is as follows:
(1) mixing the aforementioned amounts of NaF, AIF3, LIF and KF, and heating the résultant mixture until the mixture Is moiten, and then adding the aforementioned amount of AI2O3 to obtain a melt;
and (2) ralslng the température of the melt prepared In step (1) to 760’C and then carrylng out electrolysis, wherein in the electrolysis process, the eiectrlc conductivity of the electroiyte is about 1.8Ω*1·ατΓ1, the denslty Is about 2.05g/cm3 and the saturation concentration of alumlna Is 6%.
Embodiment 3
The components of the electroiyte In this embodiment are as follows: 20% of NaF, 66% of AIF3, 4% of UF, 4% of KF and 6% of AI2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3is 0.6.
The performances of the electroiyte in this embodiment are measured and the measurement resuit Is that the liquldus température of the electroiyte in this embodiment is 640’C.
The electrolysis process using the electroiyte in this embodiment is as foilows:
(1) mlxing the aforementloned amounts of NaF, AIF31 UF, KF and Ai2O3, and heating the résultant mixture to form a melt; and (2) ralslng the température of the melt prepared in step (1) to 730’C and then carrylng out electrolysis, and quantltatively supplylng AfeOsin the electrolysis process, whereln in the electrolysis process, the eiectric conductivity of the electroiyte is about teff^cm*1, the denslty is about 2.03g/cm3 and the saturation concentration of alumlna is 5%.
Embodiment 4
The components of the eiectrolyte in this embodiment are as foilows: 21% of NaF, 60.1% of AiF31 10% of UF, 5.9% of KF and 3% of ΑΙ2Ο31 wherein the molar ratio of NaF to aluminum fluoride AIF3is 0.7.
The performances of the electroiyte In this embodiment are measured and the measurement resuit is that the liquldus température of the electroiyte in this embodiment is 640eC.
The electrolysis process using the electroiyte in this embodiment Is as foilows:
(1) mixing the aforementloned amounts of NaF, AIF31 UF, KF and Ai2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared In step (1) to 750’C and then carrying out eiectroiysis, and quantitatively suppiying AI2O3ln the electrolysîs process, wherein In the electrolysls process, the electric conductivlty of the electrolyte is about 1.8Ω'’·αη·1, the density is about 5 2.04g/cm3 and the saturation concentration of alumlna is 6%.
Embodiment 5
The components of the electrolyte In this embodiment are as follows: 20% of NaF, 60.1% of AIF3,3% of LiF, 13.9% of KF and 3% of AI2O3> wherein the molar ratio of NaF to aluminum fluoride AIF3 is 10 0.67.
The performances of the electrolyte In this embodiment are measured and the measurement resuît is that the iîquîdus température of the electrolyte In this embodiment is 620*C.
The eiectroiysis process using the electrolyte In this embodiment is as follows:
(1) mixing the aforementioned amounts of NaF, AIF31 LiF, KF and AI2O31 and heating the résultant 15 mixture to form a melt; and (2) raising the température of the melt prepared in step (1) to 720’C and then carrying out electrolysls, and quantitatively suppiying AI2O3in the electrolysls process, wherein In the eiectroiysis process, the electric conductivity of the electrolyte is about l.eQ^cm'1, the density Is about 2.03g/cm3 and the saturation concentration of alumlna Is 5%.
Embodiment 6
The components of the electrolyte in this embodiment are as follows: 20% of NaF, 61% of AIF3, 9% of LiF, 4% of KF and 6% of Ai2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3 Is 0.65.
The performances of the electrolyte In this embodiment are measured and the measurement resuit 25 Is that the ilquidus température of the electrolyte In this embodiment Is 670’C.
The electrolysls process using the electrolyte in this embodiment Is as follows:
(1) mixing the aforementioned amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared in step (1) to 760’C and then carrying out electrolysis, and quantitatively suppiying AI2O3in the electrolysis process, wherein in the electrolysis process, the electric conductivity of the electrolyte is about l.eQ’^cm'1, the density Is about 2.05g/cm3 and the saturation concentration of alumina Is 6%.
Embodiment 7
The components of the electrolyte in this embodiment are as foilows: 13% of NaF, 60% of AiF3,10% 10 of UF, 12% of KF and 5% of Ai2O31 wherein the molar ratio of NaF to alumlnum fluoride AIF3 is 0.43.
The performances of the electrolyte in this embodiment are measured and the measurement resuit is that the liquidus température of the electrolyte in this embodiment Is 660’C.
The electrolysis process using the electrolyte in thls embodiment is as foilows:
(1) mixing the aforementioned amounts of NaF, AiF31 UF, KF and AI2O3, and heating the résultant 15 mixture to form a meit; and (2) raising the température of the melt prepared In step (1) to 760*C and then carrying out electrolysis, and quantitatively suppiying AI2O3in the electrolysis process, wherein in the electrolysis process, the electric conductivity of the electrolyte is about 1.8Q'1ecm’1, the density is about 2.05g/cm3 and the saturation concentration of alumina is 6%.
Embodiment 8
The components of the electrolyte In thls embodiment are as foilows: 32% of NaF, 57% of AIF3, 3% of UF, 4% of KF and 4% of AI2O3, wherein the molar ratio of NaF to alumlnum fluoride AIF3is 1.12.
The performances of the electrolyte In thls embodiment are measured and the measurement resuit 25 is that the liquidus température of the electrolyte in this embodiment is 640*C.
The electrolysis process using the electrolyte in this embodiment is as foilows:
A (1) mixing the aforementioned amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared in step (1) to 720*C and then carrying out electrolysis, and quantitatively supplying AI2O3ln the electrolysis process, wherein in the electrolysis process, the electric conductivity of the electrolyte ls about Uff^cm'1, the density is about 2.03g/cm3 and the saturation concentration of alumlna ls 5%.
Embodiment 9
The components of the electrolyte In this embodiment are as foilows: 38% of NaF, 50% of AIF3, 2% of UF, 5% of KF and 5% of AI2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3ls 1.52.
The performances of the electrolyte In this embodiment are measured and the measurement resuit Is that the liquidus température of the electrolyte In this embodiment is 670’C.
The electrolysis process using the electrolyte In this embodiment is as foilows:
(1) mixing the aforementioned amounts of NaF, AIF3, UF and KF, and heating the résultant mixture until the mixture ls molten, and then adding the aforementioned amount of AI2O3 to obtain a melt; and (2) raising the température of the melt prepared In step (1) to 760’C and then carrying out electrolysis, wherein in the electrolysis process, the electric conductivity of the electrolyte is about 1.8Q‘’*cm·1, the density ls about 2.05g/cm3 and the saturation concentration of alumlna ls 6%.
Embodiment 10
The components of the electrolyte In this embodiment are as foilows: 32% of NaF, 57% of AIF3, 3% of UF, 4% of KF and 4% of Ai2O3, wherein the molar ratio of NaF to aluminum fluoride AIF3ls 1.12.
The performances of the electrolyte In this embodiment are measured and the measurement resuit is that the liquidus température of the electrolyte In this embodiment ls 640°C.
The electrolysis process using the electrolyte In this embodiment ls as foilows:
(1) mlxlng the aforementioned amounts of NaF, AIF3, UF, KF and Ai2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared in the step (1) to 730C and then carrying out electrolysis, and quantitative ly supplying A)2O3)n the electrolysls process, wherein In the electrolysis process, the electric conductivity of the electrolyte ls about 1.6Q'1*cm'1, the denslty ls about 2.03g/cm3 and the saturation concentration of alumlna ls 5%.
Embodiment 11
The components of the electrolyte In this embodiment are as follows: 32% of NaF, 57% of AIF3,3% of UF, 4% of KF and 4% of AI2O3, wherein the molar ratio of NaF to alumlnum fluoride AIF3 is 1.12.
The performances of the electrolyte in this embodiment are measured and the measurement resuit is that the liquidus température of the electrolyte in this embodiment ls 640* C.
The electrolysls process using the electrolyte in this embodiment is as follows:
(1) mlxlng the aforementioned amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raising the température of the melt prepared In step (1) to 750*C and then carrying out electrolysls, and quantltatively supplying AI2O3 In the electrolysls process, wherein in the electrolysis process, the electric conductivity of the electrolyte is about 1.8ù'1*cm'1, the denslty is about 2.04g/cm3 and the saturation concentration of alumlna 1s 6%.
Embodiment 12
The components of the electrolyte In this embodiment are as follows: 30% of NaF, 60% of AIF3,1% of UF, 6% of KF and 3% of Ai2O3, wherein the molar ratio of NaF to alumlnum fluoride A1F3 ls 1.0.
The performances of the electrolyte in this embodiment are measured and the measurement resuit is that: the liquidus température ofthe electrolyte In this embodiment ls 620* C.
The electrolysls process using the electrolyte in this embodiment is as follows:
(1) mixing the aforementîoned amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raisin g the température of the melt prepared In step (1) to 720°C and then carrying out electrolysis, and quantitatively suppiying AI2O3 In the electrolysis process, wherein in the electrolysis process, the electric conductivity of the electrolyte 1s about 1.6Q'1«cm·1, the density is about 2.03g/cm3 and the saturation concentration of alumina 1s 5%.
Embodiment 13
The components of the electrolyte In this embodiment are as follows: 38% of NaF, 54% of AlF3, 4% of UF, 1 % of KF and 3% of A12O3, wherein the molar ratio of NaF to aluminum fluoride A1F3 Is 1.4.
The performances of the electrolyte In this embodiment are measured and the measurement resuit is that the liquldus température of the electrolyte In this embodiment Is 670* C.
The electrolysis process using the electrolyte in this embodiment Is as follows:
(1) mixing the aforementîoned amounts of NaF, AIF3, UF, KF and AI2O3, and heating the résultant 15 mixture to form a melt; and (2) raislng the température of the melt prepared In step (1) to 760eC and then carrying out electrolysis, and quantitatively suppiying AI2O3 In the electrolysis process, wherein In the electrolysis process, the electric conductivity of the electrolyte Is about 1.8Q'1»cm‘1, the density Is about 2.05g/cm3 and the saturation concentration of alumina 1s 6%.
Embodiment 14
The components of the electrolyte In this embodiment are as follows: 34% of NaF, 49% of AIF3, 5% of UF, 6% of KF and 6% of AI2O3, wherein the molar ratio of NaF to aluminum fluoride A1F3 Is 1.39.
The performances of the electrolyte In this embodiment are measured and the measurement resuit 25 Is that the liquldus température of the electrolyte in this embodiment is 660* C.
The electrolysis process using the electrolyte in this embodiment Is as follows:
(1) mlxing the aforementioned amounts of NaF, AIF31 UF, KF and AI2O3, and heating the résultant mixture to form a melt; and (2) raislng the température of the melt prepared In the step (1) to 760“C and then carrying out electrolysls, and quantitatlvely supplying A12O3 in the electrolysis process, wherein In the electrolysis process, the electric conductivlty of the electrolyte Is about l.eù'^cm'1, the density Is about 2.05g/cm3 and the saturation concentration of alumlna Is 6%.
The electrolytic cells used In the electrolysls processes in the aforementioned embodiments are continuous pre-baked anode electrolytic cells having an anode current density of 0.8A*crrï2. The electrolyte described In the présent Invention Is applicable to any electrolytic cell In the prior art.
Detailed description has been made to the spécifie contents of the présent Invention In the aforementioned embodiments, and it should be understood by those skilled In this art that Improvements and detail variations in any form based upon the présent invention pertaln to the contents that the présent Invention seeks to protect.
Claims (8)
- Clalms1. An electrolyte for aluminum electrolysls, belng composed of the following components by mass percent: 20-29,9% of NaF, 60.1-66% of AIF31 3-10% of LIF, 4-13.9% of KF and 3-6% of AI2O3, wherein the molar ratio of NaF to AiF31s 0.6-0.995; or being composed of the following components by mass percent: 30-38% of NaF, 49-60% of A1F3, 1-5% of UF, 1-6% of KF and 3-6% of Al2O3, wherein the moiar ratio of NaF to AIF3 is 1.0-1.52.
- 2. The electrolyte according to claim 1, characterized in that the molar ratio of NaF to AIF3 is 0.6-0.7 or 1.12-1.52.
- 3. The electrolyte according to claim 1 or 2, characterized In that the liquldus température of the electrolyte ranges from 620 to 670’C.
- 4. The electrolyte according to daim 3, characterized In that, the liquldus température of the electrolyte ranges from 640 to 670’C.
- 5. The electrolyte according to any of daims 1-4, characterized in that, the electrolysis température of the electrolyte ranges from 720 to 760’C.
- 6. An electrolysis process using the electrolyte for aluminum electrolysis according to any of daims 1-5, comprising the steps of:(1) mixing spedfied amounts of NaF, AIF3, UF, KF and A12O3, and heating the résultant mixture to form a melt; or mixing spedfied amounts of NaF, AIF3, UF and KF, heating the résultant mixture until the mixture Is molten, and then adding Al203to obtain a melt; and (2) ralslng the température of the melt prepared in step (1) to 720-760’C and then carrying out electrolysis.
- 7. The eiectroiysis process using the electrolyte for aluminum eiectrolysis according to daim 6, characterized in that the melt prepared In step (1) is eiectroiyzed at 730-750’C.
- 8. The electrolysis process using the electrolyte for aluminum electrolysis according to daim 6 or 7, characterized in that AI2O3is quantitatively suppiied in the eiectrolysis process.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210188422.7 | 2012-06-11 | ||
| CN201310024018.0 | 2013-01-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| OA17185A true OA17185A (en) | 2016-04-05 |
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| Mean | CURRENT EFFICIENCY |