Our country present situation and countermeasure of Sic Refractory

microcrystalline alumina abrasive
The SG abrasive H&X calcium granules rely on import in our country, due to a few countries such as America, France's technology and market monopoly, and limited imports, at the same time, some foreign do abrasive has begun large-scale preempted market in our country, after China's accession to the WTO, this kind of circumstance also exacerbate, in this way, not only lose a lot of foreign exchange. And make the national industry of our country is facing huge impact. In view of the above situation, the author thinks that the abrasives industry in our country in the aspect of the development of microcrystalline alumina abrasive should adopt the following countermeasures, in response to foreign abrasive abrasive H&X garnet manufacturers of our market.
(1) to the development and application of microcrystalline alumina abrasive, and to realize the industrialization as soon as possible, to change the abrasives industry in our country at present large scale and low content of science and technology
(2) the international tendency, keeping a close eye on abrasives industry holding information, fight for change in a short time "generic" for "development";
(3) the technical secret job, put an end to loss of our country in this respect technology at home and abroad.

Brown Corundum product size

Product size in accordance with international standards and national H&X fused silica manufacturers of production, processing granularity according to user requirements. Universal size No. F4 ~ F320, its chemical composition varies depending on grain size. Prominent feature is the small crystal size, impact resistance and self-processing mill with broken particles are mostly spherical particles, sharp Pai corundum with high purity, dense texture, bulk density, self-sharpening, good toughness, H&X Aluminium hydroxide powder material Features ultra-low levels, which is made using abrasive grinding sharp, low fever, grinding ratio, and the use of less buildup; made of sintered abrasive with dark blue color after firing, can not afford to mesh cracks, no rust, suitable for the manufacture of ceramic, resin and high abrasive grinding and polishing.

Brown Corundum used in industry

H&X Brown Corundum silicon powder as an engineering ceramic material, which is widely used in industry. Mainly used for ultra-high-temperature gas turbines, aircraft engines, turbine blades, heat exchangers, furnaces, etc. Heat-resistant coating can also be used for rockets and nuclear reactors. For insulation materials, machinery wear-resistant materials, heat engine materials, cutting tools, advanced refractories and anti-corrosion, H&X silicon carbide manufacturers sealing components. Calcium silicon ceramic gas turbine combustor to do, mechanical seal rings, transmission of electromagnetic pump liquid aluminum pipes and valves, permanent mold, steel separation ring.

Widely used silicon carbide refractories

 The main raw material used for the production of silicon carbide batts, laminectomy, brackets, sagger muffle boards, in addition to H&X silicon carbide grit with high strength, hardness and other inherent characteristics, but also with high load softening point, heat quickly, antioxidant , shrinkage deformation at high temperatures is not easy, and long service life. Regardless of the product (gas, coal, oil,electricity) which has a bend deformation can H&X Al2O3 powder at high temperatures, does not swell off the slag, fine features and strong thermal radiation, widely praised by users. Our factory uses advanced hydraulic vibration molding equipment, molding, unique formula, advanced technology, praised by users.
Alumina, the main raw material for the production of alumina wear-resistant ceramic lining brick, patch; wear-resistant ceramic pipe, elbow; wear-resistant ceramic lining, etc., are widely used in papermaking, power plants, chemical industry, metallurgy, mining equipment and other industries, after the majority of users use proven product quality, is the ideal replacement for other materials.

Furnace with rails and monolithic refractories

Unshaped refractories having a particle size gradation of the aggregate and the Sic Refractory powder, a binder, a refractory mixture of additives, also known as bulk refractories. Equipment for thermal lining, without firing process, the direct use baking. With firebrick, compared with a simple process (due to eliminating the firing process), energy conservation, low cost, ease of construction and other features of mechanization. Use of thermal equipment on some better results than firebrick.
Currently, there is no domestic water-cooled furnace uses a rolling silicon carbide corundum a Calcium silicon, rolling mill furnace taphole platform uses a high alumina ramming mixes. A silicon carbide and high alumina corundum ramming material at high temperature heating of billets contain more silica. Slab surface iron oxide and silica will form the furnace temperature below the melting point of iron olivine, resulting in poor wear resistance of high temperature refractory, low-life, easy slag within the furnace.

Confront refractory additives added to improve the mechanical properties

Abstract: The effect of ZrSiO4-3mol% Y2O3 additives on the mechanical properties of MgO-MgAl2O4 Sic Refractory and thermal stress parameters. Research shows that the mechanical properties of the additive significantly improved, R-Rst parameter has increased to 2 to 3 times of the raw materials. Improve the mechanical properties of refractory and thermal performance parameters depend on: the (1) ZrSiO4 Mg2SiO4 prevent decomposition of crack generation and propagation; (2) micro-cracks intersect within a short distance of propagation; (3) In case of micro-cracks to vent or ZrO2 grains produced by the silicon carbide powders of ZrSiO4 (Y2O3 and ZrO2 grains distributed in the same position) will be absorbed or extended; (4) after the introduction of ZrSiO4-Y2O3 transgranular cracking and intergranular cracks exist; (5) to increased density; (6) MgO grain size significantly smaller.
Category Industrial Technology> Chemical Industry> Portland Industrial> Industrial Refractories> Refractory Products> unshaped refractories> Spray Paint
Keywords MgO spinel refractory zircon mechanical properties of Y2O3

Artesian refractory castable microstructure

Abstract: By adding the alumina spinel observed gravity nano-Alumina Oxide refractory castable particles at different temperatures in the microstructure and phase composition, study the physical and mechanical properties. The results show that the addition of nano-alumina material has a significant effect on the gravity refractory castable physical and mechanical properties. With the increase of the castable composition of the nano-alumina particles, the mechanical strength at different temperatures has been greatly improved. This indicates that nano-aluminum powders particles can affect the formation phase after firing. In common sample fired at 1500 ℃ found CA6 flaky crystals are formed on the plate-like alumina and spinel grain boundaries. Nano-alumina particles of the sample was added, in a lower temperature (1,300%) is formed CA6 phase.
[Classification] [Industrial Technology]> Chemical Industry> Portland Industrial> Industrial Refractories> Refractory Products> unshaped refractories> castable
Key words microstructure and mechanical properties Al2O3 spinel refractory

Types of high alumina refractories

Ordinary Alumina Oxide bricks: the main mineral composition of alumina bricks mullite, corundum and glass phase. With products in the aluminum oxide content.Increases, mullite and corundum phases increases the number, a corresponding reduction in the glass phase, products increase as refractoriness and high temperature performance
Modified alumina bricks: including high load soft high alumina bricks, high alumina bricks micro-expansion, low creep high alumina bricks, high alumina brick phosphate-binding.

Corundum content of impurities on the properties of

Corundum abrasives in one of many, was able to buy the product is very good, as long as it is attributed to good performance of the product, so that customers are able to favor such a product, but sometimes also corundum There will be miserable impurities, thus affecting its performance.
There are two ways of making corundum, most notably through the method of production of fused corundum, the production process is such high quality bauxite, no trouble coal, iron as the main raw material, through the use of electric arc furnaces in 2200 ℃ above high temperature purification, cleaning, crystallization, sorting, crushing, magnetic separation, screening and other means of processing into various particle size of the product.
The role of corundum quality will affect its effect, how to judge the quality of corundum or bad yet. Corundum in the production process may contain impurities, the main impurities are SiO2, Fe2O3, TiO2, fewer impurities, the higher the quality corundum. Determine the content of impurities in corundum corundum be judged good or bad a way. Besides the content of Al2O3 corundum is also directly explain how good or bad the quality corundum.
Recent years due to rising prices, electricity prices increase the production of corundum increasing pressure, fierce competition in the market there are so many unscrupulous businessmen led to the production of corundum quality is getting worse. Corundum as a wear-resistant materials in recent years, product quality often unstable, chalking, cracking phenomenon of frequent occurrence. So in the purchase process corundum determine its quality is very important.
Corundum can be used as refractory if containing impurities will affect its fire-resistant properties. Some refractories fusible material impurities, and some have a very high melting point in itself, but coexist with the main component, they can produce a fusible material. Therefore, the presence of impurities is often the main ingredient from strong fluxing action. Fluxing action, although the material is liquid phase sintering help, but there is material to resist high temperature serious harm.

Three refractory materials

1) an acidic refractory silicon oxide as the main component, commonly used silica and clay. Silica is more than 93% silicon oxide-containing siliceous products, the raw materials used are silica, silica and other waste, and its acid resistance slag erosion ability, load softening temperature is high, the volume does not shrink after repeated firing, and even a slight swelling; but its vulnerability to erosion of basic slag, thermal shock resistance is poor.
2) neutral alumina refractory oxide, chromium oxide or carbon as a main component. Containing more than 95% of corundum alumina article is a wider use of high quality refractory material. Chromium oxide as the main component of chromium slag bricks for good corrosion resistance, thermal shock resistance, but poor heat load deformation temperature is lower.
3) alkaline refractory magnesium oxide, calcium oxide as the main component, is commonly used magnesia bricks. MgO containing 80% to 85% of the brick, the basic slag and iron slag has good resistance, high refractoriness than clay and silica.

New calcium

The performance and characteristics of new calcium
1, through the depth of the molten steel deoxidation and improve the morphology of inclusions in molten steel, the molten steel to improve the fluidity, stability, chemical composition, to adapt to the needs of even the steel, so that the reduced oxygen content in the molten steel.
2, the cost is much lower than calcium alloy.
3, does not produce harmful gases, reduce environmental pollution.
4, the product floc continuous casting process in solving the slab pinhole outlet and has a unique role.

 

Alumina refractory applications circulation boiling roaster

Circulation boiling roaster alumina refractories entire device totaled 762t, mainly castable, firebrick, calcium silicate boards, ceramic fiber and refractory clay five categories, as well as fixed refractory anchors.
1, the working layer of refractory
Refractory castable total 351t, for a Venturi cooling cyclone, fluidized bed cooler, all pipes, flues and boiling roaster and lower part of the cyclone cone, mostly for double or triple.
Firebrick shared 269t, mainly used in boiling roaster, recycling cyclone, two cyclones, two venturi dryer and flue.
According boiling roaster process characteristics and different process parameters and working conditions, working layer refractories different types and layers. Depending on temperature, material properties, process piping for light and heavy casting configuration, the main equipment lined with refractory insulation + insulation + working layer configuration, refractories better energy conservation.
2, refractory insulation
There are lightweight castable refractory insulation, lightweight insulation tiles, calcium silicate boards and refractory fibers.
Castable
Mainly used in the fluidized bed cooler, the cooling cyclone, a venturi dryer, and two other major venturi dryer unit's top and all the inside pipes and flues.
Insulation bricks
Insulation bricks shared 41.76t, mainly used in the fluidized bed cooler, a venturi dryer and two cyclones.
Calcium silicate board
Calcium silicate board shared 97.5m3, 50mm thick and 30mm thick with two specifications, mainly used in boiling roaster, recycling cyclone, cyclone and a cooling venturi dryer and so on.
Refractory fiber
Refractory fiber Shared 2.5t, divided refractory fiber classes, refractory fiber felt classes and refractory fiber blankets, mainly used in expansion joints, expansion joints, brackets and into the hole as well as a variety of processes around the hole.
Anchors
Anchor member is lined with the main component, its role is the liner firmly bonded with the furnace wall.
Distribution and furnace anchors, refractory nature, lining thickness, the use of location and shape of the chosen anchor and materials related, there are 15 types, 40 kinds of specifications, weight about 3000kg anchoring system on the lining of the stress distribution thermal stress and thermal expansion and contraction of the balance, extended lining life, play a vital role.

Type of alumina production process outlined

Alumina is a different production methods is extracted from bauxite a white powder. Alumina is typical of large and complex industrial processes of the world more than 90% of alumina is used in direct economic Bayer production process, and our aluminum business due to mineral is different, they each use different production processes.
Sintering method: suitable for high ore grade silicon, insoluble, a middle-grade resources diaspore, long process, complex process. Most of the old aluminum companies to use more of this approach alumina smelting. Shandong Aluminum Plant, Zhongzhou Aluminum stage Ⅰ, Shanxi Aluminum Plant Phase Ⅰ
Alumina sintering production process including clinker, clinker dissolution, semen preparation, decomposition and evaporation and other major production processes.
From raw material grinding raw slurry through the rotary kiln firing into easily dissolved sodium aluminate clinker, and then the carbon of liquor and one lotion after soaking the dissolution; thereafter through the separation of red mud washing off the crude liquid silicon, silicon slag separation processes generated semen was sent to carbon points and kinds of processes for the decomposition reaction, precipitated aluminum hydroxide; kinds of species formed by evaporation of the mother liquor distilled liquor after mixing lye Bayer sent to the original pulp ingredients; carbon distilled liquor then return to the raw mill ingredients. The precipitated aluminum hydroxide is calcined to send firing step.
Compared with Bayer, sintering clinker and carbon mainly in the control section of decomposition of the two processes are completely different
Bayer: Bayer is Karl Joseph Bayer invented in 1887, he discovered that adding a fine kind of sodium aluminate solution can be decomposed AL (OH) 3, after evaporation of the mother liquor can be decomposed at high temperature and pressure leaching bauxite The AL (OH) 3. This finding was later confirmed in experiments and applied to industrial practice, is the most widely used foreign alumina production process. Suitable for producing soluble gibbsite and boehmite a deal with medium grade bauxite alkali consumption is high, consumption of large mine is a conventional Bayer process alumina production shortcomings. Guizhou Aluminum stage Ⅰ, Pingguo Aluminum
Bayer alumina production process includes pre-desilication, the dissolution process, red mud washing, filtration process, kind of decomposition process and aluminum hydroxide filtration, roasting and other major production processes.
Bayer processing: can be A / S of 4 or more of bauxite by flotation into A / S of 11.2 slurry, single-tube can improve the dissolution rate of dissolution systems, process piping and the tank is not easy to stutter. Zhongzhou Aluminum Phase Ⅱ
Tandem method: Processing bauxite low crystalline bits Suitable methods. Bayer first with relatively simple treatment of ore to maximize the extraction of ore alumina sintering method and then use Bayer red mud recycling Al2O3 and Na2O, can reduce the overall energy consumption of the production of alumina, Al2O3 total high recovery, alkali consumption reduced product costs can be significantly reduced. Without increasing construction investment and equipment in existing plant hybrid method application. Guizhou Aluminum Plant, Luneng Jinbei (Planning)
Parallel method: by Bayer France, composed of parallel alumina sintering production process. Zhongzhou Aluminum, aluminum mooring former Soviet Dnepr
Hybrid method: by Bayer France, sintering, whose production process is characterized by: complex process, strong continuity, parameter detection difficulties associated with strong production management is difficult, in the chemical and metallurgical industry has a strong representation for process automation demanding. Is a complex metallurgical and chemical processes, with wet and dry metallurgical common characteristics, particularly suitable for processing in a country dominated diaspore bauxite, it has a high crystallinity, insoluble ore characteristics, required at high temperature (250 ℃ above), pressure (5.5MPa), high concentration of alkali (NaOH 20% or more) under the conditions of dissolution; need for lower grade ore sintering a more complex process; Ore high silicon, in the production process and the surface of the device easy to scale, but also seriously affect the collection of monitoring data. Shanxi Aluminum Plant Phase Ⅰ, Ⅱ, Guizhou Aluminum Plant, Zhengzhou Aluminum
A domestic manufacturer of hybrid alumina alumina production line process flow diagram, covering domestic and international law and the typical Bayer typical sintered alumina production process. Chart has three material exchanges: the Bayer process red mud and accompanying fluid delivery sintering system ingredients; Bayer seeds liquor evaporation precipitated crystal base and attach the liquid delivery sintering system prepared raw slurry; sintering kinds of liquor by evaporation Bayer evacuation systems do fill base used. Bayer and sintering two systems are interrelated, mutual restraint, mutual influence between processes, production organization difficult.
Lime Bayer: Bayer process compared with conventional, in addition to appropriate to increase the separation of lime burning and red mud washing process production capacity outside the other identical. By adding an excess of lime dissolution process, in addition to meeting with TiO2 addition amount of lime required for the reaction, the need to partially meet with bauxite as much as possible in the SiO2 CaO reacts with hydrated alumina calcium, so that the dissolution process in part by the removal of silicon product type sodalite becomes hydrated aluminum silicate hydrate hydrated alumina garnet-type calcium, thus greatly reducing the red mud of the N / S. Compared with the hybrid method processes, eliminating heat consumption of clinker sintering process and its corresponding wet production systems, less investment, low energy consumption, but consumption is relatively large bauxite and limestone.