The extracting method of rafifinal and equipment
Technical field
The invention belongs to aluminum smelting technology purification techniques, particularly a kind of method of producing the refined aluminium product of purity more than 3N.
Background technology
China Shi Yige Aluminum big country, the output position of electrolytic aluminum is at the forefront in the world, but the most of dependence on import of rafifinal (the aluminium product of purity more than 3N), although in the 2O century 8O age, the domestic research that starts to carry out this respect, but the improvement of production technique only applicable purity is lower than the aluminium products production of 3N, slower to the research of 3N rafifinal production technique.As everyone knows, rafifinal is applied widely in industry such as low temperature electrotechnology, electronic industry and robot calculator, astronomical telescope, petrochemical complex, nuclear power, radar, aerospace, electromobile and semi-conductors, and its consumption increases year by year.But the present domestic enterprise that can produce the 3N ultra-pure aluminum of meeting consumers' demand is very few, and research and development unit is also very few, it is reported by 2010, to only have only a few producer production purity to reach 99.9% rafifinal.In the international market, also only virtuous, Mei,Fa, E,Deng state possesses throughput, therefore domestic required rafifinal major part needs import, although domestic, there is enterprise at trial production ultra-pure aluminum, but with external similar enterprise and domestic next than there being larger gap to ultra-pure aluminum requirement, exist in many ways not enough.First be equipment, technique relative complex, it utilizes multidisciplinary art, makes cost of investment excessive, and inconvenience grasp is controlled; Next is to discharge in impurity efficiency, unsatisfactory, can not produce qualified product; It three is that energy consumption is higher, more than reaching 15000KWH/ ton, disagrees with national energy-saving reduction of discharging policy, although decrease at present, also has ten thousand degree left and right; Its four, although produce product, quality is still unstable, and demestic user cannot be used.Specifically, existing conventional ultra-pure aluminum is produced heating and is all electromagnetic induction heating stirring synchronously, adopt low-voltage and high-current, electrical equipment power factor is less than O.3 left and right, and cannot compensate by super-capacitor, a large amount of power consumptions, because the latent heat of fusion of aluminium is greater than more than 400 times of specific heat, make more than 80% power consumption for melting aluminum.How solving an above-mentioned difficult problem, is the domestic needs task of top priority.
Report and patent about rafifinal also have, and below with regard to us, retrieve some and comment:
1, " mechanical engineering journal " fourth phase in April, 2006, " novel 5N high-purity aluminum purification device principle and control ", summary: have purifying technique and equipment by comparative analysis, in conjunction with the coagulating property of pure metal, independent development has gone out a set of equipment and corresponding technique that is applicable to suitability for industrialized production 5N rafifinal.Equipment adopts twin coil two-region Frequency Induction Heating, has obtained higher and adjustable thermograde, by the speed of growth of computer controlled automatic crystal, controls the grain form in directional freeze, has obtained the uniform born of the same parents' shape crystalline substance of growth and monocrystalline.Composition detection demonstration, the aluminium ingot purity of preparation reaches more than 99.9993%, and impurity element axial distribution is reasonable.By cutting head and end, can obtain the finished ingot that massfraction is qualified.The method of document report is to adopt twin coil two-region Frequency Induction Heating, belongs to method of purification and the device of high energy consumption.
2, " foundry engieering " 2008 third phases, investment 100Wan Yuanyu Shanghai Communications University of Nantong Tai Erde clothes company limited Materials Academy is carried out the pure purification techniques tackling key problem of aluminium.Through the research trial more than 4 years, by controlling the growthhabit of the brilliant material of aluminium, improve the impurity element segregation efficiency in vertical orientation process of setting, thereby carry the cleanliness factor of High-Alumina, successfully develop the ultra-pure aluminum that purity reaches 5N5.Through Shanghai Inst. of Silicate, Chinese Academy of Sciences, detecting. product meets international standards completely.It is reported, the method is to adopt segregation method to purify, the shortcomings such as lifetime length.
3, Chinese patent title: a kind of purification method of ultra-pure aluminum, the patent No.: 200910309668 patentees: open day: 04 month 21 Granted publication day in 2010: on 05 11st, 2011, invention designer: base, Changhai, Changsha City High & New Technology Industry Development District, Hunan Province North Floor 4, summary, a kind of purification method of ultra-pure aluminum, it comprises: select refined aluminium purity to be at least 4N6, and Mg < 6ppm wherein, Ti < 0.2ppm, the raw material refined aluminium of Zr < 0.2ppm, and cleaning and drying; The raw material refined aluminium of selection is packed in purification furnace, and this purification furnace is airtight, vacuumize, and be heated to 680 ℃-750 ℃ with gas furnace, make raw material refined aluminium be molten into liquid by solid; Again the purification furnace that is heated to 680 ℃-750 ℃ is moved in crystal growing furnace, this crystal growing furnace heater heats makes constant temperature in crystal growing furnace keep 660 ℃, in purification furnace, aluminium liquid rotatablely moves in crystal growing furnace well heater, by the heat dissipation capacity of crystallization control stove, make the aluminium liquid in purification furnace certainly maintain crystallization velocity 5-10cm/h, through 4-6 hour post crystallization, finish; Purification furnace after crystallization is cooling, take out crystallization ingot, from the afterbody of crystallization ingot, remove the 25%-35% of crystallization ingot weight, the aluminium ingot that obtains purifying for the first time; The aluminium ingot of purifying is for the first time put into purification furnace again, repeat to purify, until obtain the aluminium ingot that meets purity requirement.
4, Chinese patent title: method and the smelting furnace thereof of directional freeze purification rafifinal; application (patent) number: CN201110224938.8; open (bulletin) number: CN102277505A; application (patent right) people: Xinjiang Zhonghe Co. Ltd.; address: No. 18, East Road, Keshen, Urumqi City, Xinjiang Uygur Autonomous Regions scientific and technological management portion of Xinjiang Zhonghe Co. Ltd., invention (design) people: turbulent waves; Make great efforts Gu Yiming, summary: a kind of method and smelting furnace thereof of directional freeze purification rafifinal, the method of this directional freeze purification rafifinal by selecting materials with the first step, second step melting, the 3rd step solidify purification, the 4th step and obtain finished product and carry out, this smelting furnace comprises furnace shell, heating unit, container, whipping appts and refrigerating unit; In furnace shell, be installed with container, between furnace shell and container, interval is installed with the heating unit of many from top to bottom; Furnace bottom place below container is provided with refrigerating unit, and furnace bottom temperature measuring equipment is installed between refrigerating unit and furnace shell.The inventive method has advantages of that energy consumption is low, treatment capacity is large, efficiency is high, product purity is high, can be used for producing in enormous quantities the rafifinal of 5N to 6N.Smelting furnace reasonable and compact in structure of the present invention, easy to use, it is used in conjunction with by heating unit, bottom cooler, furnace bottom temperature measuring equipment, can greatly increase work efficiency, thereby improve the quality of the rafifinal out of purifying.Principal claim: a kind of method of directional freeze purification rafifinal, is characterized in that carrying out according to the following steps: the first step, select materials, select the aluminum feedstock of purity 4N to 5N, and physics is carried out in the surface of above-mentioned aluminum feedstock and clean; Second step, melting, puts into smelting furnace purification container by ready aluminum feedstock in the first step, and aluminum feedstock is heated to 670 ℃ to 730 ℃, makes aluminum feedstock get whole fusings, obtains aluminium liquid; The 3rd step, solidified purification, by the aluminium liquid of second step gained at 670 ℃ to 730 ℃ standing 7 minutes to 80 minutes; Then cooling to implementing at the bottom of smelting furnace, aluminium liquid is implemented to heating, the temperature of aluminium liquid is upwards controlled within the scope of 660 ℃ to 700 ℃ from low to high from crystal plane, from the furnace bottom crystallization that makes progress, within 1 hour to 8 hours, obtain crystallization ingot, in crystallisation process, stirring rake pre-heating drying is placed in aluminium liquid and implements Stirring or/and implement induction stirring; The 4th step, obtains finished product, according to the difference of purity demand, removes 15% to 70% part of thickness from the afterbody of crystallization ingot, obtains the rafifinal of required purity.The method exists can only obtain a crystallization ingot at every turn, and energy consumption is high.
5, Chinese patent title: a kind of efficient high-purity aluminum purification device; application (patent) number: CN201110264876.3; open (bulletin) number: CN102321811A; application (patent right) people: clothing celebrating ripple; address: No. 301,9-2 building, acrobatic skill street, Xinfu District, Fushun City, Liaoning Province unit 8, invention (design) people: clothing celebrating ripple; Liu Peng; Clothing Na; Sun Yufei; Yi Qing army; Jiang Jie; Former Jianchang; Wang Jingsong; Zhao Zhihao; Wang Shulei; Zhang Ying, summary: a kind of efficient high-purity aluminum purification device, comprise the furnace shell that is supported on support, the electromagnetic resistance boiler clothing in furnace shell and by electromagnetic resistance boiler clothing around cylindrical pot body; Electromagnetic resistance boiler clothing is that blade end vertical, that the columnar structured ,Qi of 12 blade top outwards turns down is power connection end; Described cylindrical pot body consists of folded top purification compound pot and the bottom purification ingot casting compound pot dropping on together; The feed inlet and outlet of purification compound pot is sealed by blind flange, and its upper outside is provided with supporting cup; The lower end of purification ingot casting compound pot is supported in Tuo Sheng mechanism.The upper and lower alternate repetition heating of two pot bodies of this invention is purified, and working efficiency has obtained great lifting.Pot body promote or decline process in, all the time another pot of body wherein carried out to preheating, not only avoided the waste of electric energy, waste electric energy and obtained great reduction, but also increased substantially the Quality and yield of rafifinal product, reduced running cost.Principal claim: a kind of efficient high-purity aluminum purification device, comprise electromagnetic resistance boiler clothing (1) in the furnace shell (20) that is supported on support (6), furnace shell (20) and by electromagnetic resistance boiler clothing (1) around cylindrical pot body; Electromagnetic resistance boiler clothing (1) is that the blade end that the columnar structured ,Qi of vertical blade top outwards turns down is power connection end (15); It is characterized in that: described cylindrical pot body consists of folded top purification compound pot (2) and the bottom purification ingot casting compound pot (3) dropping on together; The feed inlet and outlet of purification compound pot is sealed by blind flange, and its upper outside is provided with supporting cup; The lower end of purification ingot casting compound pot is supported in Tuo Sheng mechanism.The device for extracting high pure aluminum of the document belongs to the purifying plant of high energy consumption.
Except the disclosed rafifinal electromagnetic resistance of above-mentioned document stove smelting process, general rafifinal preparation technology also has condensation method, three layers of liquid electrolytic process, segregation method, unidirectional solidification method, zone melting method and Steppecd crystallization both at home and abroad now.In order to compare several method, we list following technique contrast:
1, condensation method
Aluminium liquid remains on certain temperature, and the cooling crystallizer with water-cooled is inserted in aluminium liquid, will go out the crystal that purity is high in crystallizer crystallization around, by rotation xln, increases flowing of solid-liquid interface, improves the diffusion effect of solute.The refining effect of this technique is general, but production efficiency is higher.
2, three layers of liquid electrolytic process
By Hoopes, in 1901, invented, so far have the history of more than 100 year, three layers of liquid electrolytic process purification precision and production efficiency are higher, the purification precision of three layers of liquid electrolytic process can reach 4~5N, but its energy consumption is large, meanwhile, in electrolytic process, produce obnoxious flavour and the waste electrolyte serious environment pollutions such as hydrogen fluoride, carbon monoxide, sulfurous gas;
3, segregation method
Segregation method is the method that while utilizing alloy graining, segregation phenomena is purified, and main method has (1) crystal refining method respectively, (2) directional freeze method for refining.This method can not be produced continuously, and production efficiency is low, and residual aluminum liquid exists secondary pollution to the aluminium of having purified.France Pu Ji company of packet header Aluminum group company (Pechiney) now belongs to the rafifinal project of the throughput 10 k t/a of Nowe power (Novelis) Chinalco introduction, in December, 2007, goes into operation.
4, unidirectional solidification method
By forcing cooling or heating, control the direction of growth of crystal, make to solidify direction and deviate from hot-fluid direction of transfer with a kind of method of continuous unidirectional crystallization despumation element, utilize the technology of induction stirring, the liquid phase in solid/liquid interfaces forward position is carried out to enforceable stirring, can reduce the thickness of solute enriched layer in the liquid phase of forward position, interface, be conducive to the diffusion of solute, improve the efficiency of purifying.
5, zone melting method
Be the main method of purification rafifinal, be mainly used to produce the ultra-pure aluminum of 5N5~6N5.The investigator of Japan has carried out dark people's research to this technique, finally obtained the fine aluminium of 7N.
In above-mentioned several technique, because 3 layers of liquid electrolytic process production rafifinal energy consumption are large, the U.S., Canada, Germany, Japan, France and the state such as Russian, most rafifinal product more and more trends towards utilizing the segregation legal systems such as unidirectional solidification or fractional crystallization standby, with billet supply market.
Described Steppecd crystallization is a kind of novel method that fine aluminium is smelted always, it is that molten aluminium temperature in crucible is remained near fusing point, in melt, insert the crystallizer of water-cooled, impel crystal to grow on crystallizer, when crystal grows into a certain degree, adopt scrape division by the solids accumulation of crystallization to crucible bottom, then by insulation, squeeze the liquid that the low melting point of wrapping up between crystal is rich in to impurity and extrude, this kind of method can make 80 of primary aluminum amount obtain refining, and purity can be brought up to 4 N5 by 3 N5.It is as follows that the 8th phase of " light metal " nineteen ninety is introduced Steppecd crystallization working method in detail.Electrolysis primary aluminum liquid as raw material is packed into plumbago crucible, and the gas cooling aluminium liquid in graphite cooling tube, goes out primary crystal in cooling tube crystallization around.Then, ring-type plunger is pumped, cooling tube primary crystal is around scraped to below, and with plunger to scrape below crystallizing cycle apply little force of compression.In this technological process, little crystallization sintering becomes large crystallization.The large crystallization of part melts again, and is compressed by plunger, and the mother that the contaminated liquids that lattice is asked is pressed against top steeps part.Owing to repeatedly carrying out this operation, make highly purified solid layer separated with the liquid level that contains impurity.The primary aluminum dropping into approximately has 80% can be by refining, and refining process finishes can adopt a refining unit that fascinates to discharge containing the assorted liquid level certainly of matter, or after whole metal freezings, the impure part on excision refining ingot casting top, just obtains rafifinal.
But the Steppecd crystallization of above-mentioned introduction is because needs are used ring-type plunger, operating process more complicated, and be not easy to control the crystallization of fine aluminium.
Summary of the invention
The object of this invention is to provide a kind of method and apparatus that improved Steppecd crystallization is carried out to aluminium purifying, by present method and device, can access the above fine aluminium product of 99.9% (3N), present method energy consumption is low, easily operation.
To achieve these goals, the present invention has adopted the method for improved fractional crystallization, it is the aluminium liquid of melting (aluminium water) to be injected to the middle part of one-level crystallizer, at suitable temperature, fine aluminium starts crystallization (not arriving zero pour), density diminishes, rising (floating) is to top of crystallizer, and the metal of impurity does not arrive Tc, be deposited to the middle and lower part of crystallizer, aluminium liquid from crystallizer under stirring condition exports inclined tube, under the effect of gravity, enter the middle part of secondary crystallization device, the temperature of crystallization control device, proceed secondary crystal, carry out three grades always, level Four or multistage crystallization, just can obtain rafifinal more than 99.9%-99.99%, deliver to follow-up production line and manufacture high-end aluminum products, for example do the anode foils that electrolytic condenser is used, capacitor lead wire, unicircuit wire, vacuum-evaporation material, the stable conductor of superconductor, the matrix metal of disk alloy and high-fracture toughness aluminium alloy etc., in the whipping process of secondary crystallization device, three grades of crystallizers or the above crystallizer of level Four, except fine aluminium can move forward, the impure aluminium liquid of part can return to previous stage crystallizer from aluminium liquid outlet inclined tube, re-starts purification, the impure aluminium liquid of part also can be discharged from the impurity aluminum outlet pipe of rear one-level crystallizer bottom, by control valve, return to previous stage crystallizer and continue operation, through multi-stage mold, the impurity of last step concentration in reach process increases, and makes the purification that fine aluminium can be continuous, there is more polymictic aluminium liquid to deliver to impurity aluminum container, can regularly deliver to impurity aluminum container by control valve, for example, as producing common aluminium, the raw material of door and window aluminium section bar, aluminum pot, bike aluminium section bar or general industry aluminum products,
In order to preserve fine aluminium crystal, the temperature of second crystallizer need be close with the temperature of first crystallizer, by well heater and the temperature sensor of crystallizer inside, controls.
In continuous purification fine aluminium process, aluminium liquid analytical sampling mouth or automatic metal analysis of components sensor can be established in the top of every one-level crystallizer, middle part or bottom, control at any time the molten metal aluminium content of every one-level crystallizer.
The extracting method of rafifinal of the present invention can adopt vacuum operating, or drops into nitrogen or argon gas enters crystallizer operation.
The fusing point of fine aluminium is 660 ℃ in theory, so injecting the aluminium liquid of one-level crystallizer can be in heater heats to 690-700 ℃, at the temperature of 670 ℃-680 ℃, produce crystallization, after fine aluminium crystallization, density diminishes, under stirring condition, from aluminium liquid, export inclined tube, under the effect of gravity, enter the middle part of secondary crystallization device, there is the temperature of aluminum liquid of impurity crystallizer below also more than fusing point, the fine aluminium content of secondary crystallization device may be than one-level crystallizer low, can return to process furnace by control valve A, again enter one-level crystallizer recrystallization.
The equipment that the extracting method of rafifinal of the present invention adopts comprises process furnace, aluminium liquid storage tank, 2 or 2 above crystallizers, fine aluminium container and impurity aluminum container, process furnace is delivered to one-level crystallizer by the heating of aluminium liquid, there is aluminium liquid inlet tube at one-level crystallizer middle part, aluminium liquid outlet inclined tube is arranged at every grade of crystallizer top, lead to the middle part of next stage crystallizer, impurity aluminum outlet pipe and control valve are arranged at crystallizer bottom, each crystallizer bottom impurity aluminum can pool together, by control valve, return to process furnace, again enter one-level crystallizer recrystallization, or connect impurity aluminum container and connect common aluminum production line.
In the extraction equipment of rafifinal of the present invention, each crystallizer is installed agitator, and described agitator can adopt mechanical stirrer and magnetic stirrer.
For crystallizer fine aluminium crystallization outlet can be flowed, can establish in crystallizer bottom heating unit, temperature sensor and chemical composition detecting sensor, to the heating of crystalline aluminium liquid, make temperature and the composition of its smooth crystallization control device, and grasp the time of crystallization.
The extraction equipment of rafifinal of the present invention can adopt vacuum operating, or drops into nitrogen or argon gas operation, and it is identical that the non-oxygen that concrete equipment adopts with other Metal smelting is smelted structural principle, is not described in detail herein.
The principle of work of the extraction equipment of rafifinal of the present invention:
Material is from centre enters crystallizer, at crystallized region, produce crystal, under stirring condition, the fine aluminium of part crystallization is from outlet inclined tube, flow to next stage crystallizer, impurity aluminum can be by outlet inclined tube along with rising is back to the crystallizer of previous stage, or discharge from the impurity aluminum outlet pipe of rear one-level crystallizer bottom, returns to previous stage crystallizer continue operation by control valve.
The relation of continuous multi-stage fractional crystallization and single-stage crystallization, is similar to the relation that chemical substance rectifying and single-stage are distilled.
Utilize method of the present invention, the aluminium ingot that contains the multiple elements such as Si, Fe, Cu, Pb, Zn, Ca, Ti, Cd, Ag, In can be isolated after fractional crystallization to the above fine aluminium product of 99.9%-99.999% (5N), good separating effect, do not need the heating of melting again aluminium bar, process has been saved mass energy.
Beneficial effect of the present invention:
1, the extracting method of rafifinal of the present invention is actually improved Steppecd crystallization, existing Steppecd crystallization is fine aluminium cooling taking-up at once after crystallizer crystallization, obtain aluminium bar, by analysis, obtain the chemical content data of each portion of aluminium bar, then use mechanically cutting impurity aluminum, so both wasted the energy, the aluminium bar obtaining is also irregular, and what have is short, some length, produce refined aluminium product composition inconsistent, sometimes also melting heating again.
2, the extraction equipment of rafifinal of the present invention can utilize existing aluminium melting equipment to improve, as long as crystallizer insulation is good, easily, by-pass valve control can adopt computer control mode in operation, completes automatization and controls.
Accompanying drawing explanation
Fig. 1 is the technical process of extracting method and the annexation figure of equipment of rafifinal of the present invention;
Fig. 2 is the phasor containing the aluminum silicon alloy Purification of Aluminum of 3.0% silicon.
Sequence number and component names in figure: 1, process furnace, 2, aluminium liquid storage tank, 3, aluminium liquid inlet tube, 4, one-level crystallizer, 5, aluminium liquid outlet inclined tube, 6, secondary crystallization device, 7, three grades of crystallizers, 8, level Four crystallizer, 9, refined aluminium product line, 10, control valve, 11, well heater, 12, temperature sensor, 13, agitator; 14, impurity aluminum outlet pipe; 15, impurity aluminum container; 16, common aluminum production line; 17, impurity aluminum recycle control valve.
As shown in Figure 1, extraction equipment comprises process furnace 1, aluminium liquid storage tank 2, four crystallizers respectively, one- level crystallizer 4,6, three grades of crystallizers 7 of secondary crystallization device, level Four crystallizer 8, aluminium liquid inlet tube 3 is located at crystallizer middle part, and previous stage crystallizer has aluminium liquid outlet inclined tube 5 to be connected with rear class; Impurity aluminum outlet pipe 14 is arranged at crystallizer bottom, and impurity aluminum outlet pipe 14 is provided with impurity aluminum recycle control valve 17, connects refined aluminium product line 9 after level Four crystallizer 8, and impurity aluminum outlet pipe is arranged at every grade of crystallizer bottom; Can take back process furnace 1 by impurity aluminum recycle control valve 17 and control valve 10, or connect impurity aluminum container 15 and then connect common aluminum production line 16; Also impurity aluminum can be returned to prime crystallizer from the aluminium liquid outlet inclined tube 5 of crystallizer.
Crystallizer inside is provided with well heater 11, temperature sensor 12 and agitator 13.
Embodiment
Embodiment 1
By the Si that contains of melting, Fe, Cu, Pb, Zn, Ca, Ti, Cd, Ag, the aluminium ingot of the multiple elements such as In is put into vacuum heater and is heated to 690-700 ℃, obtain aluminium liquid, contain the middle part of injecting one-level crystallizer, at the temperature of 670 ℃-680 ℃, produce crystallization, after crystallization, fine aluminium is because density is larger, be deposited in the bottom of one-level crystallizer, there is the temperature of aluminum liquid of impurity crystallizer top also more than fusing point, float over the top of one-level crystallizer, and deliver to secondary crystallization device, proceed crystallization, fine aluminium after same crystallization is deposited in secondary crystallization Qi bottom, the aluminium liquid that contains impurity floats over the top of secondary crystallization device, and deliver to three grades of crystallizers, by three grades or level Four crystallizer, to contain more polymictic aluminium liquid and deliver to impurity aluminum container, as the raw material of production general industry aluminum products, be deposited in the fine aluminium of crystallizers at different levels bottom, can further by control valve A, return to process furnace, again enter crystallizer recrystallization, through recrystallization several times, finally obtain more than 99.99% fine aluminium product, by control valve B, deliver to refined aluminium product line, manufacture high-end aluminum products.Can to each element of one-level crystallizer bottom different heights, analyze by GDMS method.
Shown in Fig. 2, in the phasor containing the aluminum silicon alloy of 3.0% silicon, vertical arrows shows and forms.Along with alloy graining, it resolves into two parts: solids component moves to phasor by aluminium direction, and impure integral part moves to right-hand.This process be physically commonly known 634 ℃ all reach the balance of temperature.Then on the pure one side of figure, have about 30% material, its Si content is 0.5%; At the other side, have 70% material, its Si content is 4.0%.This is the typical case who occurs in a batch of process, and impure is higher than pure mark far away, and degree of purification is relatively little.Through four crystallizations, can obtain more than 99.99% fine aluminium product.