Elektrolytisk aluminium
Elektrolytisk aluminium er aluminium oppnådd ved elektrolyse. Moderne industriell produksjon av elektrolytisk aluminium tar i bruk kryolitt-elektrolysemetoden for smeltet alumina. Smeltet kryolitt er løsningsmidlet, alumina brukes som oppløst stoff, karbonlegemet brukes som anode, og aluminiumsvæsken brukes som katode. Både elektrolyse.
Kinesisk navn Elektrolytisk aluminium
Hovedsakelig aluminium oppnådd ved elektrolyse
Metode Kryolitt-elektrolyse av smeltet aluminiumoksyd
Temperaturkrav 950grad-970grad
Moderne industri
Alumina brukes som oppløst stoff, karbonlegemet brukes som anode, og aluminiumsvæsken brukes som katode. Etter at en sterk likestrøm er påført, utføres den elektrokjemiske reaksjonen på de to polene i elektrolysecellen ved 950grad-970graddet vil si elektrolyse.
Aluminiumelektrolyseproduksjon kan deles inn i tre kategorier: side-innsatt anodestang selv-baketank, topp-innsatt anodestang selv-baketank og pre{{4 }}bakt anodetank.
Elektrolytisk aluminiumteknologi for selvbakende tankproduksjon har egenskapene til enkelt utstyr, kort byggeperiode og lav investering, men det er vanskelig å håndtere røykgass, alvorlig miljøforurensning, vanskelig mekanisering, høy arbeidsintensitet, ikke lett til stor-skala, lav produksjon per tank osv. Manglene som er overvunnet er i hovedsak eliminert i dag.
For tiden bruker de fleste land og produksjonsbedrifter i verden store-forstekte tanker. Strømintensiteten til tanken er veldig stor, som ikke bare har høy grad av automatisering, lavt energiforbruk og høy effekt per tank, men oppfyller også kravene i miljøvernforskrifter.
landet mitt har fullført den industrielle testen og industrialiseringen av 180kA, 280kA og 320kA moderne pre-tanker. Teknologisk forbedring og transformasjon sentrert om energisparing, produksjonsøkning og overholdelse av miljøvern har fremmet transformasjonen av produksjonsteknologi for selv-baketank til for-baketank, og oppnådd stor suksess.
I henhold til produksjonsprosessen for elektrolytisk aluminium er produksjonskostnaden for elektrolytisk aluminium grovt sett sammensatt av følgende deler:
(1) Råvarer: alumina, kryolitt, aluminiumfluorid, tilsetningsstoffer (kalsiumfluorid, magnesiumfluorid, etc.), anodematerialer;
(2) Energikostnader: elektrisitet (likestrøm og vekselstrøm), fyringsolje;
(3) Arbeidskostnader: lønn og andre administrasjonskostnader;
(4) Andre utgifter: tap av utstyr og avskrivninger, finanskostnader, transportutgifter, skatter osv.
Prosessflyt
Aluminiumelektrolyseprosess: Moderne produksjon av aluminiumsindustri tar i bruk kryolitt-aluminiumoksydsmeltet saltelektrolysemetode. Smeltet kryolitt er løsningsmidlet, alumina brukes som oppløst stoff, karbonlegemet brukes som anode, og aluminiumsvæsken brukes som katode. Det er elektrolyse. Den kjemiske reaksjonen utføres hovedsakelig av denne ligningen: 2Al2O3 pluss 3C==4Al pluss 3CO2. Anode: 2O2ˉpluss C-4eˉ=CO2↑Katode: Al3 pluss 3eˉ=Al. Anodeproduktene er hovedsakelig karbondioksid og karbonmonoksidgass, som inneholder en viss mengde skadelige gasser som hydrogenfluorid og fast støv. For å beskytte miljøet og menneskers helse, må anodegassen renses og slippes ut i atmosfæren etter fjerning av skadelige gasser og støv. Katodeproduktet er smeltet aluminium, som trekkes ut av tanken med en vakuumøse og sendes til støperiet. Etter rensing og klaring i oppbevaringsovnen støpes den inn i aluminiumsblokker eller direkte bearbeides til trådblokker og profiler.
Produksjonsprosessflyten er som følger:
Alumina Fluor Salt Karbon Anode DC
↓ ↓ ↓ ↓↓
Eksosanodegass------elektrolysator
↑ ↓ ↓
Eksosgass←Gassrensende flytende aluminium
↓ ↓
Gjenvinning av fluor, rensing og klaring
↓ ↓ ↓
Gå tilbake til elektrolysatoren
Helling Rulling eller støping
↓ ↓
Aluminiumsblokker Trådblokker eller profiler
Ligning:
Elektrolytisk aluminium er aluminium oppnådd ved elektrolyse.
Det er viktig å gå gjennom denne ligningen: 2Al2O3 pluss 3C-energisert→4Al pluss 3CO2.
Anode: 2O2ˉpluss C-4eˉ=CO2↑
Katode: Al3 pluss pluss 3eˉ=Al
The latest technology
Den nye-energisparende teknologien til elektrolytisk aluminium kommer ut, og industrien sparer 27,5 milliarder kWh strøm årlig.
On March 17, 2012, China's electrolytic aluminum industry made a new breakthrough in energy saving and emission reduction. "Low-temperature and low-voltage aluminum electrolysis new technology" successfully passed the acceptance of the Ministry of Science and Technology in China Aluminum and Power Company on the same day. It has dropped to 11819 degrees, a drop of 10.7 percent , and many technologies have reached the international leading level. If the whole industry is promoted, the annual electricity saving of my country's electrolytic aluminum industry will be 27.5 billion kwh.
After more than 30 years of development, the electrolytic aluminum industry has gradually become an important basic industry in China. However, due to the high power consumption in the production process, it has always been called a "high energy-consuming industry" and is also one of the key industries controlled by the state. The research and development of low-temperature and low-voltage new technologies is the development direction of energy saving and consumption reduction in the electrolytic aluminum industry, and it is also a major technical problem faced by the world aluminum industry.
In 2009, "low temperature and low voltage aluminum electrolysis new technology" was included in the national science and technology support plan project. Project leader Liang Xuemin and other experts in the project team made unremitting efforts to successfully develop electromagnetic and magnetic fluid stabilization technology, low-temperature and low-voltage electrolytic cell structure, and low-temperature and low-voltage process operation technology for the first time in the world. The world's leading 400KA "static flow" aluminum electrolytic cell has realized large-scale industrial production and a series of high-efficiency and stable operation at low temperature, low voltage and long cycle under high current density.
According to reports, according to the estimated domestic production of electrolytic aluminum in 2012 of 20 million tons, after the promotion of this technology in the whole industry, the annual electricity saving of my country's electrolytic aluminum industry can achieve 27.5 billion kWh, which is equivalent to 265.9 billion kWh of electricity consumption in Henan Province in 2011. More than 10 percent of the time, calculated at 0.53 yuan per kWh, directly creating economic benefits of 14.575 billion yuan, equivalent to 8.8 million tons of standard coal, and reducing carbon dioxide and other greenhouse gas emissions by 15.66 million tons, which will promote the aluminum industry and my country's energy saving and reduction. The platoon work has played a good exemplary and leading role.
Bransjeegenskaper
Alt aluminium i verden produseres ved elektrolyse. Den industrielle produksjonen av aluminiumelektrolyse tar i bruk Hall-Elu cryolite-alumina smeltet saltelektrolysemetoden, det vil si at det kryolittbaserte-fluoridsaltet brukes som fluss, og aluminaen er brukes som smelte for å danne et multi-elektrolyttsystem. Blant dem er Na2AlF6-Al2O3 binærsystemet og det ternære Na3AlF6-AlF3-Al2O3 systemet grunnlaget for industrielle elektrolytter. Den elektrolytiske aluminiumsindustrien har stor innvirkning på miljøet og er en industri med høyt energiforbruk og høy forurensning. Avgassen som slippes ut fra elektrolytisk aluminiumproduksjon er hovedsakelig CO2, og gass-fast fluorid hovedsakelig sammensatt av HF-gass. CO2 er en drivhusgass og er hovedårsaken til global oppvarming. Drivhuseffekten av CF4 og C2F6 i fluor er 6500-10,000 ganger den for karbondioksid, og vil ha varierende grad av innvirkning på ozonlaget. HF er en svært giftig gass som kommer inn i menneskekroppen gjennom huden eller luftveiene, og bare 1,5 g kan være dødelig.
Det er et problem
The actual operating index is poor. Due to the short development time, the in-depth development of China's large-scale aluminum electrolytic cells in the production field is obviously insufficient, resulting in a large gap between the production indicators of actual operation indicators and the international advanced level. Most of them operate in a large load and small grid environment, and there are many hidden dangers. The joint operation of aluminum and electricity is one of the development trends of electrolytic aluminum enterprises in China, but at the same time, there are corresponding problems in technology. Since large-capacity electrolyzers are generally large in scale (one series can produce more than 200,000 tons), and the huge electricity load is concentrated on one production series (generally more than 400,000 KW), any fluctuation in the production of electrolysis series will cause The power grid or self-provided power plants have a greater impact, and even threaten the security of power supply.
Lack of "fine design" technology and comprehensive technical measures to improve the life of the cell based on a thorough grasp of the mechanism and laws of cathode damage, it is difficult for the electrolytic cell to reach the design life and the early damage rate is high. Problems Affecting the Life of Large-scale Electric Cells in China In addition to the quality of cathode carbon materials generally considered in China, there are also some problems in the design of electrolytic cells, furnace construction materials, furnace construction quality, roasting start-up, normal production operations and production management. . The deep-seated reason for these problems is that China still lacks in-depth understanding of the mechanism and laws of aluminum electrolytic cell damage (often called cathode damage), as well as the "fine design" technology and comprehensive technical measures to improve the life of the cell based on this. With the continuous expansion of electrolytic cell capacity, the problem of cell life becomes more prominent.
Lack of advanced production operation technology, high operating costs. China's 300KA class super-large pre-baked aluminum electrolytic cells have been put into industrial application for a short time. And can not completely copy the previous experience in large pre-bake tanks (these experiences also have great limitations). The problem of uneven current distribution during the roasting start-up process is more prominent and the energy consumption during the roasting start-up process is large; the physical field (electric field, magnetic field, flow field) of the electrolytic cell after being put into operation is easy to fluctuate, and it is difficult to maintain thermal balance; It is easy to fluctuate due to external interference, and it is difficult to extinguish after the anode effect occurs, and due to the large inertia of the electrolytic cell, once the cell condition fluctuates or the cell condition is abnormal, it is difficult to quickly return to normal. As far as the overall production status of electrolytic aluminum in China is concerned, the comprehensive energy utilization efficiency is about 15 percent lower than the international advanced level, mainly as follows: the difference in current efficiency is 2-3 percentage points; The difference in energy consumption in the production process is about 3Gj/t; the difference in the consumption of electrolytic aluminum anode is 30-60Kg (equivalent to about 75-150Kg of standard coal); the difference in the life of the cell is about 1000 days; the international advanced anode effect coefficient is 0.1 times/day. Below the cell, The best level in China is around 0.3 times/day.
Overkapasitet
Since 2002, China's electrolytic aluminum industry has had a surplus of electrolytic aluminum production. Affected by the decline in demand from downstream industries, China's electrolytic aluminum surplus in 2008 is expected to reach 500,000 tons. The growth rate of electrolytic aluminum demand has slowed down. Affected by the economic crisis, the growth rate of demand from the real estate and automobile industries has dropped sharply, while the demand from the power equipment industry has maintained rapid growth. The demand for electrolytic aluminum in the packaging industry has remained stable. In 2008 The growth rate of electrolytic aluminum demand is around 10 percent . China's bauxite resources are scarce, and the bauxite resources can only be maintained for another 10 years, and it is impossible to support the average annual expansion rate of the electrolytic aluminum industry by about 20 percent . The production cost of electrolytic aluminum is between 15,000 yuan / ton and 17,500 yuan / ton, while the price of electrolytic aluminum is only 13,400 yuan / ton, and the industry has suffered serious losses. Raw materials have fallen further, and the average production cost of Chinese electrolytic aluminum enterprises is also around 15,000 yuan, so the possibility of a sharp drop in aluminum prices is very small. Around June 2009, the aluminum price may return to 15,000 yuan/ton.
When energy prices continue to rise, the world's major aluminum companies began to reduce the cost of electrolytic aluminum production in all aspects to ensure the price competitiveness of aluminum production. From the perspective of domestic policies, the national industrial policy positions the aluminum industry to meet domestic demand, and there will be differences in policies for high-precision products and low-tech products. Therefore, grasping the development trends of transportation, electric power, packaging, household appliances and other industries, and actively introducing advanced equipment, improving technical capabilities and reducing production costs have become the main development direction of the current aluminum company.
Hvordan løse overkapasiteten til elektrolytisk aluminium ytterligere
On the basis of the just promulgated "Guiding Opinions of the State Council on Resolving Serious Overcapacity Contradictions" hereinafter referred to as "Guiding Opinions", researchers from China Industry Insight Network believe that policy implementation and support should be strengthened to further suppress supply and expand demand, and improve both supply and demand. policy, and strive to resolve the overcapacity of electrolytic aluminum. Specific suggestions are as follows.
På tilbudssiden foreslås det at flere strategier bør tas for å strengt redusere produksjonskapasiteten til elektrolytisk aluminium. Spesielt bør reformen av strømprisene fremskyndes for å fjerne impulsen til raskt å utvide produksjonskapasiteten.
First, the "Guiding Opinions" should be strictly implemented, "it is strictly forbidden to build new production capacity projects", "categorically and properly handle illegal projects under construction", "clean up and rectify the construction of illegal production capacity", "eliminate and withdraw outdated production capacity", and suggest that violations can be dealt with. Fines are charged for building production capacity to establish a fund for eliminating outdated production capacity, and specific support policies have been introduced for the elimination and withdrawal of production capacity in terms of financial subsidies, enterprise conversion, and employee placement.
Second, effectively eliminate policy obstacles, implement the "integration of a group", and promote the merger and reorganization of enterprises. On the basis of entering the fast exemption/fast review channel for key industries, further study and reduce the cost of mergers and acquisitions of listed companies in the same industry; it is recommended to adjust the power policy to allow leading enterprises to build or absorb existing power generation enterprises to provide cheap electricity for their electrolytic aluminum production Supply; it is recommended to increase support in finance, taxation and other aspects, encourage leading enterprises as the main body of integration, and effectively promote cross-regional, cross-industry, and cross-ownership corporate restructuring.
For det tredje, balanser den regionale elektrisitetsprisen, fremskynd reformen av elektrisitetssystemet, og eliminer forventningen om store fortjenester. Selv om industrier som forbruker mye-energi på lang sikt har en tendens og behov for å overføres til de energirike-vestlige regionene som Xinjiang, men på kort og mellomlang sikt fullstendig overføring av produksjonskapasitet mellom regioner krever en gradvis prosess, og med tanke på transportkapasitet og ressurs- og miljøfaktorer, bør produksjonskapasitetsutvidelsen i Xinjiang og andre vestlige regioner bare på grunn av fortrinnsvise elektrisitetspriser ikke gjøres med store sprang. Derfor anbefales det å sette i verk tiltak for å balansere den regionale strømprisen og fremskynde reformen av nasjonalnettet. For eksempel kan det være det første som piloterer den elektrolytiske aluminiumsindustrien i landet, og nettilknytningsavgiften kan forenes til 1 cent til 3 cent på landsbasis, eller tillate byggebransjen på forskjellige steder. Det regionale kraftoverføringsnettverket kan eliminere ulikheten i elektrisitetsprisene forårsaket av politiske årsaker, og fjerne forventningene til relevante foretak om å oppnå overfortjeneste i vestlige regioner som Xinjiang, og dermed begrense impulsen til å investere i produksjonskapasitet, og få bedriftene til å stoppe frivillig. bygge ny produksjonskapasitet.
On the demand side, based on the current situation of sluggish external demand and escalating trade frictions, it is suggested to increase domestic demand for aluminum by means of purchasing and storing, expanding the scope of application, etc., effectively "digesting a batch", and improving the processing level of aluminum materials through technological innovation , to obtain higher returns. One is to appropriately increase the country's reserves of aluminum. The country's expansion of the scale of purchase and storage when the current aluminum price has hit a new low in two years is not only conducive to digesting part of the production capacity, promoting the preservation and appreciation of assets, but also building market confidence. The second is to increase RD and financial and taxation support, and actively expand the application scope of aluminum. The third is to actively strive to improve the processing level of my country's aluminum materials and obtain higher profits through technical research and innovation.
Tilbuds- og etterspørselssituasjon
The global production of electrolytic aluminum has grown steadily, and the driving force for the increase in production still comes from China. In 2005, the world's electrolytic aluminum output was 31.91 million tons, an increase of 6.45 percent year-on-year, of which China's output was 7.67 million tons, a year-on-year increase of 15.07 percent . In 2006, the global production of electrolytic aluminum reached 33.8 million tons. In June 2006, the global average daily output (excluding China) was 82,200 tons, an increase of 700 tons compared with the average daily output in May, and a month-on-month increase of 0.09 percent . The domestic output of electrolytic aluminum in June was 780,300 tons, and the average daily output of electrolytic aluminum was 26,000 tons, an increase of 1,975 tons compared with the average daily output in May, a month-on-month increase of 7.59 percent . China is still the main driving force for the increase in global electrolytic aluminum production. Since China's production accounts for 24.9 percent of global production, the changing trend of China's production has played a decisive role in global electrolytic aluminum supply. The development of China's electrolytic aluminum industry has determined that China's domestic electrolytic aluminum supply has always been relatively abundant. In 2005, the average production capacity of electrolytic aluminum was 10.7 million tons, and the capacity utilization rate was 75 percent . From the domestic data in June, China's production capacity has been released to a certain extent. . China has built 11 electrolytic aluminum projects with a total construction capacity of 1.12 million tons, and there are still 10 proposed electrolytic aluminum projects with a total capacity of 1.4 million tons. The production capacity of electrolytic aluminum reached 11.6 million tons in 2006 and 12.5 million tons in 2007. The electrolytic aluminum construction process is simple, the technical content is low, the construction period is short, and there is sufficient capital investment. It only takes 9 months from the start of construction to the completion and production.
The alumina production capacity of the upstream industry of electrolytic aluminum has rapidly expanded, and the industrial chain has been extended to the electrolytic aluminum industry, which has become the main driving force for the growth of electrolytic aluminum production capacity. The growth and development stage of the electrolytic aluminum industry determines that production growth is the main keynote. The competition, restructuring and mergers and acquisitions of electrolytic aluminum enterprises, continuous expansion, and increased industry concentration will also promote the growth of production capacity. The buyers of the electrolytic aluminum industry are aluminum consumers. The rapid development of China's economy and the urbanization process of China's infrastructure, public utilities, housing and automobiles and other consumer goods have greatly boosted China's electrolytic aluminum consumption demand. The electrolytic aluminum industry is in the stage of rapid development and growth, the industry survives the fittest, and the industry concentration continues to increase. From 2003 to 2005, the total output of electrolytic aluminum increased from 5.54 million tons to 7.67 million tons, an increase of 2.13 million tons, of which only the top ten electrolytic aluminum plants in China achieved an increase of 910,000 tons. The number of manufacturers decreased from 141 to 95, and the average production scale of a single manufacturer increased from 39,000 tons in 2003 to 80,000 tons in 2005.
Bransjeanalyse
From January to November 2012, China's primary aluminum output was 18.15 million tons, showing a slight downward trend year-on-year. The serious overcapacity situation has eased. By the end of October, the industry's goal of eliminating outdated production capacity of 270,000 tons has been more than half completed.
På dette stadiet bør elektrolytiske aluminiumsbedrifter unngå blindt å utvide produksjonskapasiteten, forvandle de opprinnelige industrielle fordelene til lønnsomhet og bruke eksisterende ressurser til å kombinere kullkraft, smelting og prosessering i form av originale fordeler for å danne en komplett industriell kjede og utvide skalaen. av bedriften. Det har blitt et viktig mål for elektrolytiske aluminiumbedrifter å bli større, styrke produksjonskapasiteten og foredle prosessteknologi.
Etter mer enn 70 år med utvikling har den elektrolytiske aluminiumsindustrien i New China oppnådd store prestasjoner i alle aspekter, men den står også overfor mange utfordringer og problemer som må løses ordentlig, ellers vil det være ugunstig for neste utvikling.
overkapasitet
As of the end of 2013, China's primary aluminum production capacity has exceeded 32,000kt/a, and it is necessary to develop to foreign countries to mine bauxite, extract alumina and produce aluminum ingots for remelting in places with relatively rich resources and energy. Joint venture or sole proprietorship to ship the obtained products back to the country. The amount of aluminum and aluminum products to be exported by 2020 is processed with imported aluminum ingots for remelting, not equivalent to imported aluminum resources (bauxite, alumina, scrap aluminum). By 2030, about 50 percent of the remelting aluminum ingots for domestic apparent consumption will be imported. The ideas of Japan, South Korea and Taiwan region to develop the primary aluminum electrolysis industry are worth learning from, as well as the practices of the United States and some European countries.
Going out to develop aluminum resources is risky. In some places, the risk is still very high. It may be necessary to "pay a certain amount of tuition fees". Tuition fees may be unavoidable, and strive to pay less. At present, Japan and other countries have all shut down domestic primary aluminum production (Japan also retains a Urahara aluminum plant with a production capacity of 15kt/a, which uses the power of a small hydropower station on Mount Fuji. The power station was built by an aluminum plant. The aluminum plant will then use the segregation method to extract high-purity aluminum to reduce environmental pollution), and in the past 30 years, the production of primary aluminum in industrially developed countries such as the United States and Germany has decreased. The output of primary aluminum in China has declined somewhat, while the output of enterprises abroad has risen by more than 35 percent .
In 2021, the world's per capita aluminum consumption (calculated by 7 billion people, primary aluminum consumption of 51,400kt) is 7.34 kg/person, and China's per capita aluminum consumption (calculated by 1.35 billion people, primary aluminum consumption of 25,500kt) is 18.89 kg/person , has far exceeded the world average consumption, which is 2.57 times, and is close to 21.4 kg/person of industrially developed countries. Our main task now is to improve the quality of raw material consumption and to do as much as possible with as little raw material consumption as possible. The domestic scale should no longer be expanded, and the measures of "reducing the east and increasing the west, and reducing the fire and increasing the water" can be adopted.
Tekniske utfordringer
Although the tank capacity of some electrolytic aluminum plants in China has caught up with or exceeded the world's leading level, the technical and economic indicators of similar tank types still need to be improved compared with the advanced level abroad.
At present, the anode effect coefficient of electrolytic cells of electrolytic aluminum plants in my country is relatively high; the power consumption per ton of aluminum is higher than that of the European leading level; the average cell life is generally shorter; the current efficiency of the foreign leading level has reached 96 percent , while more than 75 percent of China's The current efficiency of the enterprise is only 92.5 percent -93.5 percent , and the calculation of the rectification efficiency of a considerable number of factories is low; under the same power consumption conditions, the anode current density of Chinese electrolyzers is designed to be only 0.7-0.735A/cm2. This means that the output per unit area of the same electrolytic cell is low. Therefore, in the future, one of the main tasks of China Aluminum Electrolysis is to maximize the output per unit area of the electrolytic cell.
China's current development of electrolytic aluminum industry also has many advantages, such as the low investment per unit product of electrolytic aluminum plants, which is about 1/3 of that of industrially developed countries; the low labor cost, which is 1/5-1/2 of the corresponding labor costs in the primary aluminum cost of industrially developed countries. 4. The environmental protection requirements are low, so the investment in environmental protection facilities is also low, which should not be the case. Now is the time to increase investment in environmental protection. Thousands of saving, environmental protection cannot be saved, environmental protection standards should be raised, and those that do not meet the standards should be shut down, and environmental protection standards should become high-voltage lines.
