2017年4月25日星期二

Analysis of low cement castables for cement kilns has a strong shock resistance



Not the same product, will bring a different effect, low cement castable cement kiln to bring what effect. Low cement castables mainly bauxite as raw material, high-performance calcium aluminate cement dosage is only 2 to 6%. The main production of ingredients than: brown steel jade 15-24, silicon carbide 6-15, coke 20, white mud 12-16, tar 18-20. Calcium oxide content is low, can reduce the formation of eutectic phase, improve the refractoriness, high temperature strength and slag resistance, for the cement kiln plays a very important role.

The raw materials were dried for 24 hours and then dried at 110 ℃ for 24 hours, respectively, and heat treated at 300 ℃, 500 ℃, 700 ℃, 900 ℃, 1100 ℃, 1300 ℃ and 1500 ℃ for 3h. (PM), linear change rate (PLC), room temperature flexural strength (MOR), room temperature compressive strength (CCS), room temperature wear resistance and thermal expansion coefficient and heat resistance of the samples were measured. Seismic performance. The results show that with the increase of heat treatment temperature, the volume density of low cement refractory castable in cement kiln decreases first and then increases again. The change rate of line decreases first and then decreases The strength of the room temperature and the compressive strength at room temperature increased first and then increased. Cement kiln with low cement castable after 1500 ℃ heat treatment after the wear less than 1300 ℃ heat treatment after the wear and tear.

So that the use of low cement castables in cement kilns has a strong shock resistance. Cement kiln construction qualified rate increased by 2%, punctuality rate also increased by about 6%, it is important that the cement kiln safety factor and service life has been improved greatly, and fully reduce the cost of secondary construction of cement kiln.

What is the role of refractory cement in refractory castables

Refractory castable is made of refractory cement (10% to 15% by weight) and refractory aggregate. Therefore, refractory cement is also an indispensable part, but it also causes a series of properties of refractory castables The decline.
The main reasons for the following reasons:
1, in order to complete the hydration of cement, stirring too much water (10% to 15%) caused by ceramic refractory castable significantly higher porosity, density decreased.
2, calcium aluminate hydrate in the middle temperature stage has a strong dehydration and recrystallization effect, destroying the hard material in the castable structure, so that refractory castable in the temperature stage of the sharp decline in strength.
3, cement binder will be more calcium into the castable, resulting in ceramic refractory castable load softening temperature drop, thermal shock stability performance deterioration. In view of the problem of poor performance of ordinary refractory castable, low cement refractory castable effectively avoids the regret of high temperature performance. The so-called low-cement refractory castables, which contain less than 8% of the cement content, and less than 4% is called ultra-low cement refractory castable. In contrast, the general Refractory company castable above mentioned deficiencies are converted into low cement refractory castable advantage. Its structure is dense. Low porosity, high refractoriness, high softening temperature, high temperature strength, good thermal shock stability. But because of its low cement content, resulting in a long time of condensation, early strength in the winter and low temperature conditions, construction is particularly unfavorable. So in the masonry, to give full attention.

The difference between refractory castable and refractory cement


Refractory Castable

Refractory castable.
A kind of granular and powdered material made of adding a certain amount of binder by refractory material.It has high fluidity and is suitable for forming  refractory material.
Compared with other unshaped refractories, the binder and moisture content are higher, so the flow is better. Their wide range of applications, according to the conditions of use of the materials used and binder to be selected. Can directly cast into a lining Use, and can be made by pouring or stray method made of prefabricated block.
cement
Cement, powdered hydraulic inorganic cementitious material. After mixing with water into the slurry, can be hardened in the air or better hardening in the water, and sand, stone and other materials can be firmly cemented together. Cement is an important building Materials, made of cement mortar or concrete, durable and durable, widely used in civil engineering, water conservancy, defense and other projects.
In the insulating refractory cement plant, the use of castable material is very wide, preheater, kiln tail, three ducts, grate cooler, etc., have to use, according to working conditions, the use of different types of models, There are high aluminum anti-alkali, anti-crust, wear-resistant, and spray pipe dedicated, many kinds.

2017年4月17日星期一

The function and application of casting powder

Since the beginning of the 60s 20th century, the first time using submerged nozzle and casting powder, casting powder technology has been highly developed. Different casting powder adapted to different slab section, steel and casting process was developed. The surface quality of the billet is greatly improved and the surface of the slab is gradually improved. The basic functions of mold powder are: to protect the mold meniscus molten steel from the secondary oxidation of air; has good spread performance and thermal insulation properties, to prevent the molten steel surface solidification or crust; can absorb the float to Meniscus non-metallic inclusions;   .........................

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2017年4月5日星期三

Analysis of Refractory Sintering Process of Core Furnace

Industrial furnace iron liquid treatment, sensor removal and docking of this work for the sensor replacement of the core part of its quality and progress related to the success of the entire construction. The temperature of the furnace refractory lining can not be reduced to below 80 ℃ during the quick change process, otherwise the lining will be cracked to affect the life of the entire lining. Therefore, in ensuring the quality of construction under the premise of the progress must be. In addition, the throat cleaning is particularly important, the electric furnace throat should be as far as possible to remove the original size; docking surface of the slag must be clean, to ensure that the opposite paste Yan, or easy to lead to the interface of leakage of molten iron. To empty all the molten iron from the throat, you should protect all the hose in the pit to prevent being burned.
When the resumption of transmission for the sensor refractory material sintering, melting solid iron mold temperature reaches the left and right, that is, iron began to melt, should be injected into the furnace iron injection, or there may be broken. So the melting of the 5 - 8t molten iron in addition to the normal process by the cupola to provide, but also should be emergency prepared. If the furnace temperature measurement of the thermocouple accidental damage, should be based on changes in the coil current to determine when the liquid into the liquid, because the melting mold temperature exceeds the magnetic transition point 70 ℃ (Curie point), the cast iron organization Of the ferrite that becomes non-magnetic, the magnetoresistance increase map, according to the transformer principle, will lead to coil current surge, this time can be injected into the molten iron. The site should be prepared enough of the trough, in the new sensor for leakage of molten iron or broken trench accident, the electric furnace filled with molten iron (for 30t with a core furnace, the furnace will be up to 45t molten iron) To save the furnace refractory lining and equipment to prevent accidents to expand and reduce losses.

Characteristic Refractory Material Mud Mixing Method

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