Microsilica: a key raw material for prefabricated parts in refractories

Refractories: meeting complex requirements using different materials and formats

Refractory materials are used to provide linings in a great variety of high-temperature processing units: from 600 °C degrees in cooking ovens to over 1700 °C in hot metal treatment, via 1100 °C in petrochemical processing, 1450 °C in cement clinker sintering, etc. Refractory materials are designed and delivered based on diverse mineral and chemical characteristics and in different formats: castables, shaped products and prefabricated parts. The latter, which is the subject of this article, describe refractory materials delivered in prefabricated parts or precast components for direct installation in functional parts of furnaces and kilns. One of the main advantages in using prefabricated parts is significant reduction in installation time and therefore lower downtime in existing systems, as well as streamlining maintenance and repair of damaged parts.

Microsilica: enabling the manufacturing of versatile and sophisticated precast parts

Modular prefabricated parts provide specific thermal and mechanical features, which can be pre-tested off-site to ensure they meet customer applications before installation. This allows manufacturers to make very sophisticated forms for refractory linings outside of the burner unit, allowing kilns and furnaces to keep functioning. This also enables refractory parts manufacturers to line existing critical parts with higher-grade materials, improving physical performance and chemical resistance in the refractory shell, including:

• Protecting the integrity of critical parts from elevated temperatures, while maintaining continuous high temperature and reducing heat loss and resisting chemical attacks, as well as mechanical stress due to extreme heat or periodical heating/cooling cycles in all parts
• Preventing unwanted reactions, such as abrasion or chemical reactions, between the shell, the raw material and the end-product in all parts of the refractory

Elkem, the global leader in microsilica technology, provides several advantages for precast parts, because it enables the fabrication of more flexible parts that are easier to install and fit perfectly into existing structures. ELKEM MICROSILICA® products for prefabricated parts are customized co-products of silicon or ferrosilicon manufacturing, composed of ultrafine, amorphous spheres of silicon dioxide (SiO₂). They feature high-purity properties, which can have a strong impact on the specific characteristics needed in various applications, at high temperatures.

Typical parts made with prefabricated shapes include calciners, inlet chambers, nose rings, ear roofs, kiln hoods and slot coverings, dams and weirs in reheating furnaces, pouring tips, taphole blocks, cooler inlet throats and benches, bullnoses, insulation for roller hearth furnaces, etc.

They are also used for burner blocks and inner and bottom ceramic air and gas nozzles, as well as ladle lining (for the aluminium industry).

Here is a non-exhaustive list of our product offering for the making of prefabricated parts, many of which are also appropriate for shaped and unshaped products. Elkem experts, technicians and sales staff are available to explore the right solutions for your specific applications:

 

Discover the different silicon based materials for refractory applications, each with unique properties that are specifically crafted to meet the demands of high-temperature environments.