Refractory castable using validity period and size selection

一、Using effective period

Need watering tie with monolithic refractories, such as high temperature cement, refractory plastic, refractory castable, etc., must be checked before use its expiry date. Exceeds the material period, its performance will decline.

Unpacking refractory castable pocket, be sure to carefully view the manufacture date on the bag. Such as alumina cement shelf life of 3 to 6 months, cement vulnerable to air humidity during storage and transport and curdle, must be strictly checked.

Refractory soft plastic blank group, due to solidification into lumps, you can not using.

二、Granularity refractory castable

Refractory castable granularity shape, strength, size and composition, the quality of the masonry has a very important influence.

Check granularity shape, generally use visual methods. Such as knotted crucible induction furnace lining was prismatic granularity best with sharp corners. Check granularity intensity can be struck with a wooden hammer, watching the situation to determine its smash.

Check the size and composition of the particle size, the use of screening method. Sieving is carried out in the test chamber, which can be measured by the percentage of various particle size of the composition.

First check pattern according to the technical requirements of the stove on, pay attention to the size of the maximum size limits, and secondly to fire clay should be careful not lost too many fine parts, so as not to reduce its masonry performance.

Reason of casting refractory material for high temperature resistance

Casting refractory material, its main characteristic is high early strength, 3-7 days maximum compressive strength can reach more than 30MPa, and the disadvantage is the volume stability of temperature difference, the intensity decrease, the maximum fall by up to 40%, so the requirements for compressive strength must meet the design requirements and national standards.

The temperature reduces the strength of the main factors are: Casting reaches a certain temperature with low calcium and high alumina cement fireproof material in the heating furnace heating process (350 DEG C), dehydration, transformation of the hydrate started hydrate of cement stone structure, compactness and strength decreased, the volume of pouring material change, this time to the strength of castable the lowest point, after stabilizing. With the heating temperature up to 1100 DEG C, cement stone gradually sintering, casting crystalline refractory mullite crystal transformation. With the temperature rising, mullite crystal growing, a glass matrix liquid phase pouring material, forming a high temperature sintering shape, strength increase. At about 1300 DEG C, casting refractory material strength can reach more than 60MPa, a remarkable characteristic of refractory materials under high temperature condition for this is pouring.

Several suggestions of refractories in China exported to Japan

As people’s awareness of environmental protection and the implementation, some new environmental regulations in the future, not only the requirements of zero discharge of waste refractory material itself, but also the requirements of the refractory material used in the process, give full play to the refractory effect at the same time, produces no environmental pollution and harm to human health of hazardous substances. For example, some Japanese well-known large companies (including Mitsui shipbuilding and Nippon Steel etc.) are actively involved in the development of the manufacturing technology of waste incineration furnace. In order to reduce the dioxin content in garbage incineration furnace gas by discharge of, is now generally by increasing furnace burning temperature method to solve the. Because the furnace burning temperature increase, erosion rate of refractory materials to accelerate, make the refractory shorten service life. The best way to increase the burning furnace refractory life, aluminum chrome refractories is the use of high chromium content. But the use of aluminum chrome refractories will remain six chromium harmful in the slag and waste refractory material, resulting in the pollution of the environment. Therefore, at present Japan are developing new refractories for furnace burning.

Add a few suggestions of refractories in China export to Japan, because Japan’s sustained economic recession since 1995 and the appreciation of the yen, the Japanese iron and steel enterprises to reduce production costs, improve the competitiveness of steel products in the international market, the major steel companies have increased the volume of imports of refractories, refractories so Japanese imports surge. 1997 has reached 167204t, which imports from China accounted for the total amount of 72322t, the import of refractory 43.3% in Japan

The reasons of refractory brick collapse in the process of use

For refractory brick, we should not feel strange. With the progress of society, the application of refractory brick is more and more widely. Refractory brick appear collapse phenomenon, in the actual use so, what causes it; following the Xinmi Changxing refractory material factory is simple to give you introduced the refractory brick collapse reason

Refractory brick 1, red hot suddenly quenched with water to produce rupture and fall.

The 2 stage, oven heating rate master is not strict, temperature rise too fast, causing severe dehydration, masonry and damage due to expansion and shrinkage.

3 build stove masonry to expand stay insufficient, cracked and falling temperature after expansion.

4, the ash accumulation system, most of the metal salt corrosion of the refractory brick, embitterment of vanadium and nickel will penetrate into the refractory brick falling off caused by.

5 when the liquefied gas, heating, air flow ratio is undeserved, cause furnace blasting and vibration split off.

6, poor air flow furnace, flame directly flush furnace brick, the furnace brick thinning after a serious fall.

7, the operation too, lifting furnace temperature pressure to balance, it is strictly prohibited to excessive temperature and pressure, avoid the sharp rise in the drop, because the temperature of each layer of brick always lags behind the furnace temperature, the more rely on the outer temperature changes more slowly, if drastic changes in a short time the temperature of the furnace, brick layer between refractory brick and brick joints rupture is caused due to temperature difference is too large to generate huge internal stress. Furnace pressure will cause the sudden change, refractory brick for each layer of gas pressure can’t balance, pressure increasing and destroyed, may cause the whole refractory lining of furnace temperature fluctuation pressure serious collapse.

The role of boron carbide in castable refractory

Boron carbide refractory castable is very important to a substance; it can play a role in anti-compounds. Today, we look at the technical level to explain the important role of boron in castable.

Carbonation can make refractory castable product densification, suppression of carbonaceous refractory castable carbon compounds, but at the time of 1000 ℃ ~ 1250 ℃, Al2O3 and B2O3 reacts 9Al2O3 • columnar crystals 2B2O3, located in refractory castable the cracks in the matrix and thus decrease the porosity, temperature mobilize intensity, and the resulting 9Al2O3 • 2B2O3 crystals, volume expansion, can heal the volume is reduced, diminishing cracks.

Castable field of application of different specifications are not the same. We have to consider many factors, general used in firing big skateboard, Al2O3-SiC-C iron trough castable, as well as some high-speed non-burning carbonaceous refractory castable and Al2O3-C refractory castable, MgO-Crefractory interstitial castable general do not, due to the intervention of the elements boron affect the refractory castable using the furnace.

You can use Sic powder, metallic Al powder, metallic Si powder, ZrB6 from anti compounds such as replacing utility, aluminum casting material can be a little boric acid substitution, but pay special attention to the amount of manipulation.

These are our content up today. For more, please continue to focus on this site!

The main problems of new dry process kiln refractory materials

(1) Refractory material inner quality is not stable and the size of irregularity is a serious problem in the whole industry. The main reason is that the level of equipment for producing refractory material is too low, the management problems of the production is also more. Neither series manufacturing refractory equipment factory supply meet the transformation requirements of fixed-point production equipment, refractories enterprises benefit and decreased year by year, outdated equipment, the lack of its own functional improvements, unable to carry out technical transformation.

(2) The cement factory on refractory material selection and storage also has many problems, some kiln equipment and process many problems, even frequent stop kiln. Therefore, only a handful of kiln, the world’s advanced level of refractory material unit consumption reached 0.6-0.8kg / T, generally deviate a lot.

(3) The new dry process kiln refractory materials production capacity at present more than 10000 tons, but cannot satisfy the kiln; needs development, must have the correspondingexpansion.

(4) in recent years abroad new dry process kiln lining tends to be light, is light and ultra light materials to improve the quality, the use of an increase in the proportion of the kiln lining, the total weight of about minus 20%, further open the gap between us and them.

(5) In foreign countries are promoting the use of low chromium (Cr2O3 < 4%)magnesia chrome brick, and on the development of chrome free basic bricks of high quality. China is lack of chrome ore resources of the country, to high quality alkaline brick rapid development and production of low chromium or chromium free, can also help to reduce the chromium pollution on the environment.

Corundum products introduction

Corundum refractory materials refer to the Al2O3 content is more than products more than 90%, also known as alumina refractory products. Corundum has good stability, resistance to acid alkaline slag, glass and metal solution effect. It is in high temperature oxidizing atmosphere or use in a reducing atmosphere, can receive the good effect.

The physicochemical index of high purity corundum brick:

Al2O3 content≥99%, volume density≥3.2, apparent porosity≤18%, pressure temperature at normal temperature MPa ≥90,

Load softening temperature (0.2MPa, 0.6%) 1740℃.

Product characteristics and application:

Products with high refractoriness, good thermal stability, high temperature strength, corrosion resistance, excellent high slag resistance, small coefficient of expansion, the creep characteristics of low, spalling resistance, high temperature furnace is suitable for various conditions of use.

Widely used in zirconia ceramics fiber, fluorescent materials, electronic ceramics, magnetic materials, ceramic powder with high temperature sintering and gasifier, synthetic ammonia two reformer, carbon black reactor and glass industrial high temperature furnace and other equipment. Size, products, service life of physicochemical indexes have reached or exceeded the level of similar products at home and abroad.