The status of natural refractory mineral raw materials in China
According to relevant data: my country's high-bauxite resource reserves are 2.55.8 billion tons, magnesite reserves are 3.5-6 billion tons, and graphite reserves are 1.2 billion tons (some 2.2 billion tons). The total amount of refractory raw material resources in my country seems to be rich, but it is a resource-poor country based on an average of 1.4 billion people. After more than 70 years of mining, especially the 40 years of reform and opening up, to meet the rapid development of my country's refractory material industry, there are still a large number of exports. Refractory raw material mines use predatory and disorderly mining. Professor Li Zhijian of Liaoning University of Science and Technology predicted 10 years ago: In another 20 years, most of Liaoning's high-quality ore resources will be exhausted.
Refractory raw material resources are also raw material resources for other industries. my country consumes about 100 million tons of high-quality high-alumina bauxite each year, of which 80 million tons are used in the metal aluminum industry, 15 million tons in refractory materials, and about 5 million tons in ceramics and other industries. Due to the rapid development of the aluminum metal industry, my country's high-bauxite resources are becoming increasingly scarce, especially the contradiction between the supply and demand of high-grade ore is prominent. At present, about half of the raw materials used in the aluminum metal industry are imported. Taking the road of beneficiation, synthesis, and homogenization is a way to rationally develop high-bauxite resources. Although 80% of magnesite is used as refractory raw materials, due to serious unauthorized mining and fierce competition, a large number of high-grade ores with limited reserves have been left. In addition, it is also the raw material of metal magnesium, magnesium alloy, chemical raw material, building material cementing material, etc. About 10% of graphite is used as refractory materials, and the rest is mainly used in steel and foundry industries, as well as pencils, sealing, lubricating, and conductive materials. In addition to being used as refractory raw materials, silica is also used in glass and ceramics. Kaolin and refractory clay are used in refractory materials, ceramics, papermaking, enamel, etc.
In summary, in addition to magnesite, other refractory mineral raw materials are not used in the refractory industry in a large proportion, so it cannot be used as a refractory raw material consumption to evaluate its prospects. In addition, resources such as zircon, chromite, and sillimanite group minerals are insufficient and need to be imported.
Beneficiation and homogenization of natural refractory mineral raw materials
China's refractory raw material mines have been in disorderly and extensive mining for a long time, and there are few high-grade ores left. A large amount of fine ore and low-grade ore must be found to be available. The development of high-temperature industrial technology requires high-performance refractory materials. Only high-grade raw materials can produce high-performance refractory materials. Therefore, in order to make full use of the existing refractory raw materials resources, maintain sustainable development, benefit future generations, and treat natural Refractory mineral raw materials should follow the road of mineral processing and purification. In fact, natural mineral raw materials contain various harmful ingredients. Generally, the proportion of high-quality ore is relatively small. For example, the high-quality ore of Yangquan bauxite only accounts for 8-12% of the total reserves. The LMT-47 and LMT-48 grades of magnesite are not only rare, but also easy to be mixed with gangue minerals. Only a small part of them can be selected by hand, and most of them are extracted by thermal separation and flotation. For graphite and other natural refractory mineral raw materials, with the exception of a few rich ores, beneficiation is almost required.
Utilize waste from industrial and agricultural production
With the reduction of human resources and the enhancement of environmental protection awareness, the recycling of waste materials has attracted more and more attention, and people have realized that "garbage is a misplaced resource". The use of renewable resources in China is gradually accepted. In terms of refractories, we discarded all the waste produced and refractory materials remaining after use. Now some steel companies have specialized recycling companies to reprocess and reuse the recycled waste refractories. , To produce the same type of refractory materials, or to synthesize new refractory materials with other materials.
In fact, the waste that can be used as refractory raw materials is not limited to discarded refractory materials, and there are also many other industries. Because there are many types of refractory materials, they contain a variety of chemical components, and their manufacturing methods are diverse. There is space for all kinds of waste. For example, the paper pulp waste liquid produced in the paper industry, refractory materials are used as a large amount of binder; the silicon powder used in a large number of amorphous refractory materials is originally the product of air oxidation and condensation of SiO gas produced during the production of ferrosilicon alloy and industrial silicon; continuous casting The raw material of the fused silica shroud used for pouring steel is the discarded translucent quartz glass cuts, fragments and various waste products from the quartz glass factory; the aluminum chrome slag discharged from the production of ferroalloy is used to produce aluminum chrome bricks. The service life of Matt smelting furnace is 6 times that of magnesia chrome brick, which is an excellent refractory raw material. There are also chromium iron slag, vanadium iron slag, titanium iron slag, aluminum slag, etc. as examples of refractory raw materials; coal gangue is the general term for waste discharged during coal mine construction, coal mining and washing. Its mineral composition is basically kaolinite, and its chemical composition is mainly Al₂O₃ and SiO₂. The chemical mineral composition of coal gangue in different regions is different, and can be divided into high alumina, clay, and sandstone. It can be used for different kinds of refractory materials, such as coal gangue in Shuozhou, Datong and Inner Mongolia, containing w(Al₂O₃) 43-45%, w(SiO₂) 52-53%, and the total impurity content is less than 2%. It is synthetic Mullite, the raw material for the production of aluminum silicate fiber and high-quality clay bricks; fly ash is the waste discharged from the power generation boiler, which can be used to produce light-weight thermal insulation refractory materials, and it can also be used to make gun mud and ceramsite , Extraction of alumina, etc.; in addition, there are waste ceramics, red mud produced by alumina production, sludge produced by aluminum production, various dust removal powders, some beneficiation tailings, sawdust, waste paper, waste hemp and agriculture Produced straw, rice husk, etc. The use of waste not only reduces costs, reduces floor space, but also saves energy and reduces emissions and reduces environmental pollution. From the perspective of the quantity of these wastes: about 5.52 million tons of refractory materials remain after use, more than 5 billion tons of coal gangue piled up, about 500 million tons of fly ash discharged annually, and more than 3 billion tons of annual inventory, and annual aluminum production 100,000 tons of chromium slag, 200,000 tons of ferrochromium slag, 50,000 tons of vanadium-iron slag, 1.10-118 million tons of aluminum ash slag, etc. If these wastes, the refractory raw materials of the Al₂O₃—SiO₂ system are carefully developed and utilized, these wastes are sufficient to meet the needs of refractory materials in our country, but the basic refractory raw materials may be insufficient, and more dolomite raw materials can be considered.
Synthetic refractory raw materials
The so-called synthetic refractory raw materials are two or more natural mineral raw materials or chemical raw materials or wastes, through batching, pulverization, grinding, mixing, forming, calcination or electric melting, etc., to prepare a certain chemical mineral composition And physical properties of refractory raw materials. There are many kinds of synthetic refractory raw materials, and the synthesis methods are various. A brief introduction:
(1) It can be synthesized with the grade difference between the natural mineral raw materials themselves, such as mullite, or it can be synthesized with different natural mineral raw materials, such as the synthesis of zircon mullite with high alumina and zircon concentrate; high alumina Synthetic alumina-magnesia spinel from alumina and magnesite; synthesize magnesia calcium sand from magnesite and dolomite; synthesize magnesium-iron calcium sand from high-calcium magnesite and iron concentrate; synthesize magnesium from magnesite and zircon Zircon sand; pyrophyllite and talc to synthesize cordierite; use magnesite and secondary high-bauxite clinker as ingredients, coke as a reducing agent, synthesize Sialon-spinel composite material by carbothermal reduction and nitridation; blue crystal Stone and graphite ingredients, in-situ synthesis of AlN-SiC composite materials, etc.
(2) Synthesis of natural mineral raw materials and purified industrial raw materials, such as quartz sand and silica fume ingredients, calcined in a nitrogen furnace to synthesize silicon oxynitride; pyrophyllite and nitrogen to synthesize Sialon (Sialon); use magnesia and oxidation MgAION (MgAION) synthesized from aluminum powder and metal aluminum powder; using natural quartz plus coke or carbon black reducing agent, carbothermal reduction and nitridation synthesis of Si3N4 (silicon nitride) in a high-purity nitrogen furnace; super high alumina bauxite Iron scales are calcined in a reducing atmosphere to synthesize iron-aluminum spinel; use desilication zirconium, light burnt magnesite powder and dolomite ingredients to synthesize magnesia calcium zircon sand; use dolomite and industrial alumina ingredients to synthesize calcium hexaaluminate-tip Spar composite material; zircon reacts with alumina in situ to prepare ZrO₂---mullite composite material; dolomite and industrial alumina are used as ingredients to synthesize calcium hexaaluminate-spinel composite material Wait.
(3) Synthesize refractory raw materials between purified industrial raw materials, such as using industrial alumina and titanium dioxide to synthesize aluminum titanate; aluminum powder and nitrogen to synthesize AIN (aluminum nitride); industrial alumina and high-purity ultra-fine aluminum nitride powder Alon (Aron); use light calcium carbonate and industrial alumina, according to the stoichiometric ratio of CA6 CaO and Al₂O₃, to synthesize calcium hexaaluminate; use titanium dioxide and metal aluminum powder under the action of flowing ammonia, in situ Generate Al₂O₃-TiN composite materials, etc.
(4) Especially waste and natural mineral raw materials or chemical raw materials are used to synthesize refractory raw materials, such as the use of sludge and pyrophyllite, kaolin on the surface of aluminum profiles to synthesize mullite, and talc and pyrophyllite to synthesize cordierite; High-bauxite tailings high and low-grade ore ingredients to synthesize mullite; iron tailings and light burnt magnesia powder ingredients to synthesize forsterite; fly ash and carbon black synthesis (O+β)—sialon-mullite complex Phase materials; fly ash and industrial alumina or high alumina bauxite ingredients to synthesize mullite; fly ash, aluminum ash, carbon black ingredients, use carbothermic thermite composite reduction nitridation process to prepare Sialon powder; Panzhihua High The slag contains 22-25% w(TiO₂), which is mixed with carbon black to prepare Ti(C,N) advanced refractory raw materials by carbothermal reduction and nitridation method; the ferro-titanium slag is ground to 35μm and added with 0,9% silicon powder, After mixing, briquetting and sintering to prepare calcium titanoaluminate multiphase refractory raw materials; aluminum chromium slag and magnesia synthetic magnesia aluminum chromium spinel refractory raw materials; aluminum ash and high alumina bauxite, magnesia ingredients, iron filings as precipitant , Coke is the reducing agent, and the electrofusion method is used to synthesize aluminum-magnesium spinel; using aluminum ash and rutile as raw materials, and the metal aluminum in the aluminum ash as the reducing agent, the TiN—Al₂O₃ composite refractory raw material is synthesized by thermite reduction and nitridation method; Use sandstone coal gangue containing SiO2 and C (carbonaceous matter) to synthesize silicon carbide, also use coal gangue and coal to synthesize B-SiC; coal gangue and ceramic polishing waste slag to synthesize B-Sialon multiphase refractory raw materials; use coal gangue and waste Synthetic cordierite-mullite refractory materials, such as magnesia-carbon bricks, waste skateboards, etc.
There are many synthetic refractory raw materials, so I won't describe them more due to space problems. The concentrate or tailings after beneficiation can be synthesized directly without grinding fine ore, simplifying the production process.
Concluding remarks
Although China’s refractory raw materials resources are abundant, after more than 70 years, especially the rapid and disorderly mining of more than 40 years of reform and opening up, there are not many natural non-renewable refractory raw materials resources, especially high-quality ore. Low-grade ore, so-called "unqualified ore", crushed ore, and fine ore pile up like mountains. China is a large country producing refractory materials. The output of refractory materials accounts for 65% to 69% of the world's total output. A large number of various refractory raw materials are needed every year. If the refractory industry is to continue to develop, the current raw material resources must be integrated. Use scientific methods to carry out geological exploration, mechanized mining, beneficiation and purification, homogenization, etc. At the same time, consider the use of industrial and agricultural wastes, develop and expand on the basis of existing wastes, and conduct in-depth investigations on the chemical and mineral composition of wastes in various fields, their possible use value, treatment methods, etc., and the use of waste The direct use and synthesis of refractory raw materials with other substances, the research results of waste utilization, and the utilization of large-scale industrial production. The use of waste not only reduces costs, but also protects the environment, which is of great significance.
