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