Specific materials for specific application and challenges in refractories
Microsilica: a raw material of choice for shaped products in refractories
Refractory materials are designed and delivered with diverse mineral and chemical characteristics and in different formats: castables, prefabricated pieces and shaped products. The latter, which this article examines, are refractory materials delivered as pieces of different sizes and shapes.
Microsilica: a key raw material for prefabricated parts in refractories
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.
Microsilica: a key raw material for castable products in refractories
Refractory materials are designed and delivered with various mineral and chemical characteristics and in different formats: prefabricated parts, shaped products and castables (also referred to as monolithics).
Materials for Refractories App
Find all you need to know about microsilica and other Elkem products for refractories in this app.
Our complete product range for refractories is composed of several material families
Silica fume / microsilica
Silica fume, also known as condensed silica fume or microsilica, is a spherical sub-micron amorphous silicon dioxide used in many applications.
Silica fume is a co-product of silicon or ferrosilicon production, consisting of ultrafine (sub-micron), amorphous, non-porous, perfectly spherical silicon dioxide (SiO2) particles, with purity levels of 85 to 99 %. The main effect of these ultra-fine particles is to greatly improve particle packing and produce a highly pozzolanic reaction in concrete and other cementitious bond systems where the silicon dioxide reacts with calcium hydroxide, improving the strength development and durability of these materials.
Silicon powder / micronized silicon
Silicon powder, also known as micronized silicon, is used for many different applications.
Metallurgical silicon is typically produced in a size of 0-100 mm, but for most applications further size reduction is required. The optimum particle size depends strongly on the final application. This means that, in many cases, some optimization work is required to find the most cost competitive solution.
Specialties for refractories
Our strategy is to develop specialty products and offer complementary products that will further advance the refractories technology and create value for our customers. These products include SIOXX™ Specialties, EMSIL-DRY™ and ALOXX™-Spheres.
Boron carbide (B4C) plays a crucial role in the production of refractory items.
Boron carbide (B4C) serves as an anti-oxidant in the formulation process. Additionally, in the realm of high-performance ceramics and abrasives, boron carbide is utilized to enhance wear-resistance. At Elkem, we meticulously select our boron carbide to guarantee uniform quality, and our team of experts is readily available to offer guidance for your specific application.
Silicon carbide provides benefits for high-temperature, high-voltage and high-power applications
Silicon carbide is used for applications that require:
- Great mechanical strength, including high levels of hardness
- Great high-temperature resistance, combined to low thermal expansion and high thermal consistency
- Chemical inertness at all temperatures
- Variable electrical conductivity, including semi-conductor properties and non-linear electrical resistance
Our fused silica is mainly used in refractory, ceramic & glass manufacturing, investment casting and in other special applications.
Here are the characteristics of our fused silica:
- Uniform chemical composition with minimal impurities, resulting in exceptional high-temperature strength
- Outstanding dimensional stability, guaranteeing nearly exact castings
- Reduced thermal conductivity
- Complete absence of cristobalite
- Exceptionally low coefficient of thermal expansion
- Regulated particle size distribution
Ferrosilicon nitride (FeSi3N4) is a refractory additive used in silicon-carbide and alumina-based refractories, such as taphole mixes for blast furnaces.
Ferrosilicon nitride (FeSi3N4 or FeSiN), also recognized as silicon iron nitride or nitrided ferrosilicon, is a remarkably heat-resistant compound formed through the reaction of nitrogen with ferrosilicon under elevated temperatures.
It offers protection against chemical corrosion, physical wear, and thermal stress, thereby extending the furnace's operational lifespan. Elkem's ferrosilicon nitride undergoes meticulous quality assurance, and expert application assistance is readily available.
Sustainability at Elkem
To learn more about our sustainability initiatives, check our webpage.