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refractories

High Alumina Refractory Mortar

Composition of high alumina refractory mortar, High alumina refractory mortar is made from high alumina clinker, binder and admixture. It is commonly delivered as dry bulk and needed to mix with water when used.

Admixture of high alumina refractory mortar, In high alumina refractory mortar, soft clay is added to improve its workability, such as spreadability and adhesivity. The application of fume silica powder instead of soft clay is able to reduce sintering temperature. Admixture mainly involves water-reducing admixture, stabilizer, plasticizer and anti-shrinking agent. Water-reducing admixture is able to decrease water addition; The stabilizer can prevent solid-liquid separation from adjusted refractory slurry during static process. Adding plasticizer is able to improve the spreadability of mud and prevent flowing; Anti-shrinking agent has ability to prevent cracking or peeling generated by volume shrinkage of clay joints after sintering.

High Alumina Refractory Mortar
High Alumina Refractory Mortar

Physical and Chemical Indicators

High Alumina Refractory Mortar

Item

Indicator

LN-55A

LN-55B

LN-65A

LN-65B

LN-75A

LN-75B

LN-85B

GN-85B

Refractoriness (℃) ≥

1770

1770

1790

1790

1790

1790

1790

1790

Al2O3(%)≥

55

55

65

65

75

75

85

85

Cold bending、bonding strength MPa ≥

110℃ after drying

1

2

1

2

1

2

2

2

1400℃×3h
after sintering

4

6

4

6

4

6

1500℃×3h
after sintering

6

6

0.2MPa RUL,℃ T2.0 ≥

1300

1400

1400

1650

 

Linear change %

1400℃×3h
after sintering

+1 ~-5

1500℃×3h
after sintering

+1 ~-5

Bonding time

1~3

Particle size %

-1.0 mm

100

+0.5mm  ≤

2

-0.074mm ≥

50

40

Advantages

Refractory mortar used for refractory bricks is adjusted and made from powdery refractory materials. It shall own abilities of good masonry performance and high temperature performance to bond refractory bricks into a dense integral furnace lining.

Masonry performance of slurry is that, in masonry process, refractory slurry is able to guarantee working performance of masonry quality, such as good liquidity and plasticity, and a certain performance of water retention, more specifically, it is capable of maintaining uniform state without segregation and precipitation, keeping appropriate consistency and viscidity in masonry process, and guaranteeing its certain humidity within the time of masoning bricks to achieve requirements of brick seam thickness and with full of mortar in brick seam.

The high-temperature performance of slurry is to ensure working performance of refractory bricks under high temperature. The main indexes are as follows

(1) Sufficient refractoriness;
(2) Sufficient bonding strength to combine the masonry into a solid whole under working temperature;
(3) Smaller value of dry shrinkage and residual shrinkage at high temperature, and no crack expectantly occured in brick joints after using at high temperature;
(4) Small apparent porosity and permeability, good air tightness;
(5) Good erosion resistance of coal gas, slag and molten iron;
(6) The coefficient of thermal expansion is consistent with that of firebrick. As working temperature and operating conditions of each part in blast furnace and its auxiliary equipment are different, different types and compositions of slurry shall be selected for different masonry.

Similar chemical composition to refractory bricks shall be considered in selection of refractory mortar to make thermal expansion of slurry correspond to that of slurry-bonded refractory bricks and the masonry can be guaranteed and reliably bonded.

Characteristics

(1) Good plasticity, construction convenience
(2) Good bonding strength, strong corrosion resistance
(3) High refractoriness, up to 1750℃
(4) Slag invasion resistance
(5) Good thermal exfoliation

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