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Construction of castable refractory

July 06, 2018

1.Castable Refractory Preparation

Before construction, need check mixer equipment, transportation,vibrating tools and the pouring parts intact,clean; Check the mould,the refractory brick around and insulating layer’s waterproof measures. Check the derusting,anchorage,anchorage brick form, size, layout,welding quality and expansion compensation measures for metal anchors. Check whether the quality of castables and construction water meet the requirements. In addition, during the construction time, ensure the power and uninterrupted during construction.

The formwork of the castable construction is made from non absorbent material. If use wood formwork,it needs to be coated water proof layer in order to prevent losing water. After loss water,the fluidity of the castable is reduced,hardly to remove the bubbles and vibrate to compact. The steel formwork should be coated mould release,prevent mould stick to the castable. When reuse, the formwork need to be cleaned first, then oil and use again.

2.Castable Refractory Mixing

a.It should be used compulsory mixer to mix.The mixer need to be cleaned by water before using, do not mix with lime,silt,Portland cement etc. If mixed with phosphate materials,the mixer must be cleaned totally before mixing the cement castable.

b.According to the mixer size and construction situation,the mixing capacity should not exceed 200kg. In the case of water using,must be sufficient mix to reach the fluidity.

c.Put the castable materials pour into mixer, dry mix for 3 min, then add the clean water. When add water, add 90% water volume of the reference water first to castable,then add the remaining water slowly and make slurry fluidity meet the requirement,wet mixing not less than 5 min.

d.The castable must be used in whole bag. The stirred castable should be pour quickly,from the time of adding water,it must be finished in 30 min. The initial set of wet materials,can’t be grudgingly formed, can’t use it again after water,must be abandoned.

3.Castable Refractory Vibrate

a.The mold should be compacted,prevent leakage of pulp.The pouring castable should be vibrated layer by layer by vibrator asap,the thickness can’t exceed 300mm,the vibrating distance is about 250mm.Do not vibrate repeatedly, in case segregation.

b.When vibrating,avoid touching anchors parts,and do not damage the insulation layer, after the castable surface bleeding and most of bubbles are discharged,pull out the vibrator slowly.

c.Pouring should be carried out continuously. Before the last layer of castable is set,the next layer castable construction should be carried out in time. If the construction interval exceeds the initial setting time, the construction joint will be treated as requires.

4.Castable Refractory Maintenance

a.To the cement bonded castables, after surface dried, the part which in the exposed air, cover tightly with the plastic or bags. However, the chemically bonded castables do not need cover the surface.

b.After final set,the mold of castable can be dismantled,but the bearing plant can be removed after the strength up to 70%.

c.The curing temperature of the castable refractory should be 10~35℃ .When the temperature is too high, the hydration products will be change to C3AH6,which may lead to the strength decrease. The hardening will be delayed by the low temperature.

castable refractory