QHow to choose firebricks?
There are many factors to be considered when you choose the firebricks for your kiln, the most suitable bricks not only can improve the kiln service life but also save your money.
1. It depends on your kiln. The kiln can be divided into new masonry kiln and old kiln maintenance masonry. If the new one, we should know which parts,using temperature, special environment (acid alkali, high pressure,impact, wear and so on) of the firebricks to be used? Then choose the most suitable firebricks. If maintenance for old kiln , it can be based on experiences use of firebricks before, considering whether to use another materials instead, or improving and enhance the firebricks index.
2. According to the use part and working temperature or other speciications such as the cold crushing strength, the porosity, the creep rate, the linear change etc to choose and produce the firebricks to saticefy the production requirements.
QWhy do castable precast blocks have construction advantages?
The compressive strength of castable precast blocks is high.
This performance is about 2 times higher than that of the conventional product.
(2) The thermal shock resistance is good.
The thermal shock resistance of castable precast blocks can be improved by 8 to 10 times.
(3) Excellent wear resistance.
QWhat factors should be considered in the selection of lining materials for circulating fluidized bed boiler (CFB boiler)?
The performance of CFB lining materials should have the following requirements:
1. The inner circulation vortex type turbulent bed lining requires high wear resistance, high temperature resistance and erosion resistance;
2. The lining of the inlet section of the high temperature external circulation separator requires high wear resistance and high temperature resistance;
3. The inlet of the medium temperature external circulation separator requires high wear resistance and high temperature resistance;
4. Medium and high temperature external circulation separator cylinders require heat resistance, heat insulation and low thermal inertia;
5. Ignition combustor flue requires high heat resistance;
6. The suspension chamber requires high heat resistance, wear resistance and low thermal inertia.
QWhat are the advantages of refractory plastic?
1. High refractoriness, the refractoriness of aluminium silicate refractory plastic can reach to 1750~1850℃ ,exceed the clay bricks which can be used directly in contact with the flame.
2. Good resistance to shock cold and heat, it won’t be peel when the temperature changes dramatically. The service life of refractory plastic is longer for half year than refractory bricks.
3. Good insulating performance. The thermal conductivity of refractory plastic is smaller than brick, therefore, less heat loss, it can reduce fuel consumption.
QWhat are the causes of wear and peeling of refractory bricks in steel blast furnace lining and how to repair it?
Causes of damage to refractory bricks used in blast furnace lining:
1. Mechanical reasons in the blast furnace smelting process.
2. Chemical corrosion such as the reaction between the alkali metal oxide and the refractory brick.
3. High temperature action of the blast furnace itself.
4. In addition, due to the unreasonable design and construction of the furnace wall of the blast furnace itself, for example, poor quality refractory materials, unreasonable operation during the production process etc.
Methods for repairing blast furnace lining
QHow to set the most reasonable proportion of the aggregate when make castable?
There is a great relationship between the fluidity of the unshaped castable and the proportion of the castable trace agent and the material selection, it’s not significant with the ratio of the aggregate. In general, the fluidity of the castable should be considered from the properties of itself first, which is divided into acid, neutral ,alkaline, weak acid, weak alkali and so on. It can greatly improved the fluidity of the castable if add a certain amount of silica fume reduce using amount of the cement and greatly increase strength of the castable, but we all know that most of the silica fume is used as industrial secondary product, because of the quality stablity is not good,it may affect the overall usability of the castable.
QHow to select the heat-resisting steel fibers used for steel fiber refractory castables?
Firstly weigh the refractory aggregates, powders, binders and admixtures, and dry-mix for one minute;
Secondly add water and wet mixing, and evenly spread the steel fibers into the material, and do not clump;
Finally mix for one minute can be discharged.
The total mixing time must not be less than 5 minutes. When the vibrating rod is used for molding, the vibration direction should be staggered to make the distribution of the steel fiber reasonable, which can improve the performance.