SPECIALIST EQUIPMENT
LEFT: Refbond nano-gel on a brick This image shows a fired test cube ABOVE: Crushed test cube - with the bond still intact
WHY CHOOSE GEL-BONDED LININGS?
Fondu”. Conventional castable mixes were made by adding CAS to a crushed refractory aggregate keeping the particle size distribution in mind to balance different fractions of aggregates and fines. Since then, constant improvements and developments have targeted the improvement of performance of castable to match the performance of refractory bricks. Te fundamental development aim was to reduce the porosity of the castable to match the porosity of bricks. As a rule of thumb, we can conclude that the mixing water multiplied with the density of the aggregate results in the porosity. For example, a conventional castable uses 10%
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efractory castable has been around since the invention of calcium- aluminate cement (CAS) in 1908 by Lafarge, also known as “Ciment
fumed silica and reactive and calcined alumina to build up the matrix from the finest commercially available particles. Today’s low cement and ultra-low cement castable use between 4-6% water, which brings them in line to perform equally to refractory bricks.
Manfred Rösch details the technology that reduces cost of ownership of refractory lined vessels
water multiplied with 2.5Kg/m3 equals
25% porosity. Compared with a refractory brick of 12-14% it is easily understood why conventional castable cannot match the performance of bricks. When this was understood by developers, a constant drive led to mixes with a reduced CAS and with the addition of finer micro particles of
GEL-BONDED CASTABLE Gel-bonded castable has been around since the turn of the century. Tis relatively new bonding technology brings many advantages. Te gel- bonding is a no-cement, no-hydration technology to set castable with ultra-fine nanoparticles. With these nanoparticles, we can
now build the particle size distribution of a mix from a smaller base and therefore build much denser castable. Another great benefit in the use of nano particles is that these ultra-fine particles can act as anchors into the micro porosity of an existing refractory lining
Case study of a endless lining system in a ladle for ferro-manganes New
Performance campaign \Cost of lining per heat Duration of reline
Production gain/performance
Lining 100% 100%
12 days 100%
Gunning Repair
70%
115% 3 days 50%
Refbond nano-gel
100% 80%
3 days 125%
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