Lightweight Insulation Castables for Acid Furnaces

There are many types of lightweight refractory aggregates for lightweight thermal insulation castables. The choice of lightweight aggregate to prepare lightweight castables mainly depends on the use temperature of the castables. Generally, when used at temperatures below 800-1000℃, expanded vermiculite, expanded perlite or diatomaceous earth are used; when used at temperatures within the range of 1000-1400℃, lightweight clay aggregate, ceramsite, lightweight high-alumina aggregate, lightweight mullite aggregate are used; when used at higher temperatures, oxide hollow ball high-grade thermal insulation aggregate is used.

The ceramsite used in lightweight thermal insulation castables is water-selected shale ceramsite with a refractoriness of 1300℃ and a bulk density of 890kg/m3. Particles smaller than 5mm are generally crushed from large-particle ceramsite and screened. During preparation, the amount of ceramsite and binder should be matched, and the amount of water should be reduced as much as possible, so that a lightweight thermal insulation castable with excellent performance can be prepared. In order to adjust the performance, the lightweight thermal insulation castable with low bulk density uses high-quality shale ceramsite, high-alumina and mullite heat-resistant brick particles, ceramsite powder or high-alumina bauxite fine powder and binder for particle grading. The sintering agent is soft clay, the refractory powder is alumina clinker powder, the binder is aluminate cement, and the admixture is MF dispersant water reducer. In order to reduce the bulk density and thermal conductivity, some expanded perlite and floating beads are added. At the same time, the addition of admixtures and additives has greatly improved the performance. The characteristics of lightweight thermal insulation castables are low bulk density, high refractoriness, high strength, low thermal conductivity, etc., which can reduce the thermal energy consumption of industrial kilns and furnaces, and also reduce the weight of furnace linings. It is a good lining material for medium and low temperature thermal equipment such as kilns.