Challenge: How can I upgrade the performance of existing refractories to meet the more demanding requirements of today's steel and non-ferrous industries?

Solution: Although the raw materials used to formulate today?s refractory linings are numerous, choosing the right combination of raw materials can optimize the performance of refractory formulations. Synthetic minerals may be required substitutions for natural minerals.

The synthetic minerals of choice for dense refractories are tabular alumina, magnesia-rich and alumina-rich spinels, calcium aluminate cements, calcium hexaluminate bonite, calcined and reactive alumina, and silicon carbide. The specific mineral needs are defined by service temperature, frequency of thermal cycling, strength or loading requirements and service environment such as corrosive liquid or gas vapors. These synthetic minerals are available in different particle size distributions as this is a requirement for building the optimum formulation.

Almatis provides the premium aluminas necessary to enhance the overall performance formulations and meet the demands placed on today?s high performance refractories. High quality tabular and spinel aggregates offered by Almatis in the coarse and fine fractions are instrumental in achieving the ultimate chemical and thermal shock resistance due to their dense structure, closed porosity and consistent particle size distribution.

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Sag test of castables at 1,550?C / 5 hours. Tabular/Spinel castable shows no deformation versus bauxite castable which forms liquid phases and shows deformation. Pure tabular alumina lies next to brown fused alumina.

When the need is to improve the mineralogy or rheology of the matrix, the options and the opportunities are very broad. Well controlled, low water demand calcined aluminas are available to replace loosely controlled commodity aluminas. Fully ground reactive aluminas and ground aggregate minerals can replace partially ground calcined aluminas to dramatically lower the mixing water requirement, the in-service porosity, the molten metal and slag penetration, the in-service strength, and the ease of placement even in difficult installation conditions.

When pre-formed alumina-rich sintered spinel is utilized in severe service applications, such as steel ladles at 15% to 30% of a low or ultra low cement castable, slag and metal penetration is practically eliminated and erosion wear due to low strength is greatly reduced.

Almatis premium aluminas play an ever-increasing role in refractory requirements for modern steelmaking processes. Product consistency and chemical purity are critical to the successful performance of refractory formulations.

If technical assistance is required to upgrade a refractory formulation, Almatis' experienced technical support is available in each global region. Request Technical Assistance