Metallurgy refers to the extraction of metals from minerals orMetal compoundThe process and technology of making metal materials with certain properties by various processing methods.
Metallurgy has a long history of development, from the Stone Age to the subsequent Bronze Age, to the large-scale development of modern steel smelting.The history of human development integrates the development history of metallurgy.
Metallurgical technology mainly includesPyrometallurgy, hydrometallurgy andElectrometallurgy。With the successful application of physical chemistry in metallurgy, metallurgy has moved from technology to scienceMetallurgical Engineering。
The Earth was born in the vast universe 3 to 4 billion years ago.The universe is like a high-temperature smelting furnace, which gathers the reduced metal to the center and sinks it in the center of the earthearth 's core（Fe、Ni metal melt), and then sulfide layer (matte) is formed on the surface of the metal, and then oxide layer (slag) is formed on the surface. Finally, an atmosphere (equivalent to temperature and pressure atmosphere) is surrounded on the surface of the metal melt and slag, so the earth on which human beings live is formed.
Metallurgy is developed from ancient pottery.The first is copper smelting.The melting point of copper is relatively low. With the development of pottery, the working temperature required by pottery is getting higher and higher, reaching the melting point temperature of copper.In the process of pottery making, pottery was made in some places with copper, and copper naturally became an epiphyte and was found.With the gradual accumulation of experience, the ancients also gradually mastered the coppersmeltmethod.
Main technologies
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Pyrometallurgy
metallurgy
PyrometallurgyIt is a metallurgical process under high temperature.Ore orconcentrateSome or all of the minerals in are subjected to a series of physical and chemical changes under high temperature to generate compounds or simple substances of another form, which are enriched in gas, liquid or solid products respectively, so as to achieve the desired metal andgangueAnd other impurities.The heat energy required to realize pyrometallurgical process is usually supplied by fuel combustion, and also by chemical reaction in the process, such as sulfide oreOxidizing roastingAnd smelting without heating by fuel;The metal thermal reduction process is also self heating.Pyro metallurgy includes: dryingCalcination、roasting , smelting, refining,distillationAnd so on.
Hydrometallurgy
metallurgy
HydrometallurgyIt is a metallurgical process carried out in solution.The temperature of hydrometallurgy is not high, generally lower than 100 ℃. The temperature of high-temperature and high-pressure process in modern hydrometallurgy is only about 200 ℃, and the temperature can reach 300 ℃ in rare cases.Hydrometallurgy includes:leach, purification, metal preparation, etc.
1. Leaching The ore or concentrate is treated with appropriate solvent to make the metal to be extracted enter the solution in a certain ion (cation or complex anion) form, while gangue and other impurities are insoluble. This process is called leaching.After leaching, the leaching solution containing metals (ions) is obtained by precipitation and filtrationGangue mineralInsoluble residue (leached residue) made of silk.For some ores or concentrates that are difficult to leach, preparation treatment is often required before leaching, so that the extracted metal can be transformed into a compound or salt that is easy to leach.For example, conversion to soluble sulfateSulfation roastingEtc,
These are commonly used preparation methods.
1. Purification In the leaching process, some metal or non-metallic impurities often enter the solution together with the extracted metal. The process of removing these impurities from the solution is called purification.
2. Preparation of metal The process of extracting metal from purified solution by replacement, reduction, electrowinning, etc.
Electrometallurgy
Electrometallurgy is a method of extracting metal by using electric energy.According to the different effects of using electric energy, electrometallurgy can be divided into electrothermal metallurgy and electrochemical metallurgy.
metallurgy
1、electrothermalMetallurgy is a method of converting electric energy into heat energy for smelting.In the process of electrothermal metallurgy, according to the essence of its physical and chemical changes, there is little difference from the pyrometallurgical process. The main difference between the two is the source of heat energy during smelting.
2. Electrochemical metallurgy（electrolysisAnd electrowinning)electrochemical reactionTo separate metal from solution or melt containing metal salts.The former is called solution electrolysis, such as actiniumElectrolytic refiningElectrowinning with zinc can be classified as hydrometallurgy;The latter is calledMolten salt electrolysisIt not only uses the chemical effect of electric energy, but also uses electric energy to transform into heat energy, so as to heat metal salts into melts, so it can also be listedPyrometallurgyClass I.The production process of extracting metal from ore or concentrate usually includes both pyro process and wet process, even if the process is mainly pyro process, such asPyrometallurgyFinally, wet electrolytic refining process is required;In zinc hydrometallurgy, sulfurationZinc concentrateHigh temperature oxidation is also requiredroasting Pretreatment of raw materials before refining.
Technical Principles
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Metallurgy is to remove impurities (non intentional elements) in the metal solution by melting (heating to above the melting point), slag forming and deslagging, and some chemical components by deslaggingdecarbonization , deoxidation, etc. to obtain relatively pure alloy composition.The refined refining process generally belongs to the metal foundry.
Involved in metal forming industry, such as rough refining of ore processing and smelting (ferrous metal, non-ferrous metal) blanks;Reworking of blankssteel plant, ironworks, nonferrous metal purification (generally reflected in the majority of foundries)
Industry classification
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Metallurgical industry can be divided intoFerrous metallurgy industryAs well as non-ferrous metallurgy industry, ferrous metallurgy mainly refers to the production of pig iron, steel and ferroalloys (such as ferrochrome, ferromanganese, etc.), and non-ferrous metallurgy refers to the production of all kinds of metals except the former.
In addition, metallurgy can be divided intoRare metalsMetallurgical industry and powder metallurgy industry.
Development history
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In 2007, ChinaSteel industryRemarkable achievements have been made in rapid growth, structural optimization, efficiency improvement, and energy conservation in the international steel industry.The production of crude steel was 489.2408 million tons, an increase of 66.2522 million tons or 15.66% over the previous year;The production of pig iron was 469.4463 million tons, an increase of 6189.22 over the previous year, showing a relatively rapid growth trend.In the first quarter of 2008, China's steel product exports fell by 19.3% year on year, but the export amount rose by 7.6% year on year.
The scientific and technological level of China's metallurgical industry is strengthening, and the voice of "big but weak" has dropped.China should further improve the scientific and technological level of metallurgical industry.
matters needing attention
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iron making production
The ironmaking production process equipment is complex, there are many kinds of operations, the operating environment is poor, and the labor intensity is high.The main hazard sources existing in the ironmaking production process are: smoke, noise, high temperature radiation, hot metal and slag splashing and explosionBlast furnace gasPoisoning, blast furnace gas combustion and explosion, pulverized coal explosion, machine and vehicle injuries, high altitude operation hazards, etc.According to the statistics of accident data over the years, the main types of accidents in ironmaking production are sorted according to the number of accidents:scald, machine injury, vehicle injury, object strike, gas poisoning and various explosions.In addition, electric shockFalling accidentAnd pneumoconiosis, silicosis and chroniccarbon monoxide poisoningAnd other occupational diseases often occur.
The main causes of accidents are: human factors, management reasons and material reasons.The main human reason is illegal operation, followed by misoperation and physical fatigue.The main reason of management is that they do not understand or are not familiar with the operation technology, and the labor organization is unreasonable;The second is the lack of on-site inspection guidance, incomplete safety regulations, and defects in technology and design.The material causes are mainly the defects of facilities (equipment) and tools, and the lack or defects of personal protective equipment;Secondly, the protective safety device is defective andOperating environmental conditionsPoor.
steel making production
The line of high-temperature operation in steelmaking production is long, there are many kinds of equipment and operations, and the lifting operation and transportation operation are frequent. The main hazard sources are: high-temperature radiation, splashing and explosion of molten steel and slag, oxygen gun backfire combustion explosion, gas poisoning, vehicle injury, lifting injury, machine injury, falling injury, etc.The main types of accidents in steelmaking production are:oxygenTempering, molten steel and slag splashingscaldAnd explosion, lifting injury, vehicle injury, machine injury, object strike, falling from height, electric shock and gas poisoning accidents.
Statistics show that the main causes of safety accidents in steelmaking production are: man-made illegal operation and misoperation, poor working environment conditions, defective equipment, unfamiliar operation technology, lack of supervision, inspection and guidance at the operation site, incomplete or lax safety regulations, unfamiliar operation technology, defective or lack of personal protective measures and supplies, etc.
Steel rolling production
Steel rolling production is mainly composed of three main processes: heating, rolling and finishing. In the production process, the process and equipment are complex, the operation is frequent, the operating environment temperature is high, and the noise and smoke are large.Main hazard sources include: high-temperature heating equipment, high-temperature logistics, high-speed mechanical equipment, gasoxygenSuch as inflammable, explosive andToxic and harmful gases, toxic and harmfulChemicals, electrical and hydraulic facilities, energy, lifting and transportation equipment, as well as the impact of operation, high temperature, noise and smoke.
According to the comprehensive statistics of the metallurgical industry, the safety accidents during steel rolling production are relatively serious in the whole metallurgical industry, higher than the average level of the whole industry. The main types of accidents are: mechanical injury, object strike, lifting injuryscaldFalling, electric shock, explosion, etc.The main causes of the accident are: illegal operation and misoperation, technical equipment defects and protective device defects, unfamiliar safety technology and operating technology, defects in operating environment conditions, and lax implementation of safety rules and regulations.
Metallurgical production
1. Main hazards and accident categories and causes in gas production
In metallurgical production, a large amount of gas is produced and used: blast furnace gas,Coke oven gas，Converter gas，Producer gasAnd ferroalloy gas.The composition and percentage of various gases are different, and the main components arecarbon monoxide, hydrogen, methanenitrogen、carbon dioxideEtc.Gas is one of the main hazards in metallurgical production. Its main hazards are corrosion, toxicity, combustion and explosion.The main categories of gas accidents include: acute poisoning and suffocation accidents, fires caused by combustion andscaldAccident, explosion injury and destruction caused by explosion.The main reasons for gas accidents in metallurgical production are: illegal operation or misoperation, defects of equipment (facilities) and protective devices, lack of safety technology knowledge, lack of inspection guidance and monitoring measures on site, lack of or defects in monitoring devices and personal protective equipment, and incomplete accident prevention and rescue measures.
2. Main hazard sources, accident types and causes in oxygen production
Extensive use in metallurgical productionoxygen。Oxygen is easy to support combustion, and can burn with almost all combustiblescombustible gas It is very easy to explode after mixing in a certain proportion, and the main danger is easy to burn and explode.When oxygen burns, the temperature is usually very high, the fire is very fierce, and the disaster is seriousscaldAnd burn accidents are often large and deep burns, which are difficult to cure.When oxygen explodes, it is usually very strong and violent, with strong impact, destructiveness and destructiveness.Oxygen accidents in metallurgical production are mainly caused by fire, burn and explosion caused by oxygen combustion or combustion support, and the degree of damage and destruction is very serious.Analysis and statistics show thatoxygenThe main causes of the accident are: artificial illegal operation and misoperation, defects of equipment, facilities and devices, lack of safety technical knowledge and unskilled operation, etc.
Non ferrous metals
The smelting and production of non-ferrous metals includes the smelting and processing of copper, lead, zinc, aluminum and other rare metals and precious metals. The production process is characterized by complex equipment and processes, a wide range of equipment, facilities, processes and work types, cross operations, frequent operations, and many risk factors.The main hazard sources include: high temperature, noise, smoke and dust hazards, toxic and harmful, flammable and explosive gases and other substances poisoning, combustion and explosion hazards, various furnace operation and operation hazards, falling accidents, etc.
According to the statistical analysis of previous accidents, the main causes of safety accidents in non-ferrous metal smelting production are: illegal operation, unfamiliar with and ignorance of safe operation technology, defects in process equipment and technical design, failure or defect of protective devices, lack of inspection and guidance on site, incomplete or lax implementation of safety rules and regulations, and poor working environment conditions.
gold smelting
The main hazard sources in the gold smelting process are:high temperature, noise, smoke and dust hazards, cyanide and mercury poisoning, flammable and explosive gas and other substances poisoning, combustion and explosion hazards, and falling accidents.
According to the statistical analysis of previous accidents, illegal operation or misoperation, equipment (construction) and protective device defects, lack of safety technical knowledge, lack of on-site inspection guidance, lack or defects of monitoring measures, monitoring devices and personal protective equipment, and incomplete accident prevention and rescue measures.
Non-ferrous metallurgy
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The production of non-ferrous metals includes geological exploration, mining, processing, smelting and processing.With the development of science and technology, advanced physical and chemical technologies are constantly applied to the innovation of nonferrous metal metallurgy technology, making new progress in nonferrous metallurgy technology.Pyrometallurgy has been gradually eliminated due to its many shortcomings;At present, most non-ferrous metallurgical enterprises and research teams mainly focus on hydrometallurgy and electrometallurgy for production and research.
The continuous innovation of nonferrous metallurgy technology is facing many challenges, and nonferrous metallurgy is developing towards the direction of green environmental protection, marine resources utilization and the development of metal substitutes;However, the contradiction between industrial development and environmental protection, the difficulty of marine resource utilization technology, and the high cost of research, development and production of metal substitutes have not been effectively solved.
Considering many influencing factors, compared with the above research directions, the research prospect of secondary resource recovery and reuse is relatively broad;It will be another major breakthrough in nonferrous metallurgy technology if the research and development achievements of the laboratory in the early stage are applied to the production line in the later stage[1]。
