What Is Silicon Carbide 88/90?
Silicon Carbide 88/90 is a metallurgical-grade material with a silicon carbide content of 88 to 90 percent, the balance being silicon dioxide, free carbon, iron oxide, alumina and other minor constituents. It is produced in electric resistance furnaces and then crushed and screened into the particle fractions used by steel plants, foundries and refractory producers. Its value in metallurgy comes from the combination of high silicon carbide content, a predictable carbon contribution and stable reaction behavior in the furnace, which makes it a reliable and cost-efficient additive wherever chemical consistency matters.
Steelmaking Applications
In steel production, Silicon Carbide 88/90 is used as a reactive additive that participates in deoxidation while supplying both silicon and carbon. The dual function replaces separate additions of ferrosilicon and carburizer, which lowers operational cost and simplifies furnace management. Typical uses include electric arc furnaces, where it is fed in bulk or controlled doses for deoxidation and silicon supplementation; induction furnaces, where it supports precise chemical adjustment and heat stabilization; and ladle refining, where it tops up silicon and carbon during secondary metallurgy. Consistent silicon recovery and an improved carbon balance help the melt hit its target chemistry, reduce oxidation losses and improve final steel quality.
Foundry and Cast Iron Applications
Iron foundries use Silicon Carbide 88/90 for silicon correction, carbon adjustment and melt stabilization. Its predictable chemical contribution keeps iron chemistry uniform from heat to heat and reduces variability between castings. Practical benefits include predictable melt behavior for iron casting, improved pourability and surface finish of cast components, and a reduced requirement for additional carburizers or ferrosilicon. For high-specification cast iron grades, some foundries prefer a higher-purity silicon carbide grade such as 90/92, but 88/90 remains the most cost-effective solution for general foundry work where the small impurity difference does not affect the casting specification.
Refractory Applications
In refractory manufacturing, Silicon Carbide 88/90 is added to bricks, castables and furnace linings to improve thermal resistance and mechanical stability. The silicon carbide content raises high-temperature performance, while the carbon component provides oxidation resistance during furnace operation. Typical uses include industrial furnace linings, heat-resistant layers in steel and foundry furnaces, and general refractory castables and bricks. Higher-purity grades such as 90/92 may be chosen for premium refractory products, but 88/90 is widely used for cost-sensitive, large-volume refractory production where its performance is fully adequate.
Typical Specifications and Particle Sizes
Buyers specify Silicon Carbide 88/90 by silicon carbide content, impurity limits, moisture and particle size. The table below shows typical specification ranges for metallurgical use.
| Parameter | Typical Range |
|---|---|
| Silicon carbide content | 88 to 90 percent |
| Fixed carbon | 1 to 3 percent |
| Silicon dioxide | 5 to 8 percent |
| Iron oxide | 0.5 to 1.5 percent |
| Alumina | 0.5 to 2.0 percent |
| Moisture | 0.5 percent maximum |
| Common size fractions | 0 to 1 mm, 1 to 3 mm, 3 to 8 mm, 0 to 10 mm, 10 to 50 mm lumps |
Coarse lumps suit bulk furnace feeding, while finer granules dissolve faster and suit small heats and automated dosing. The particle size distribution should be matched to the feeding system to avoid segregation and dust loss.
Selection and Purchasing Considerations
Choosing the right grade and size requires defining the furnace type and process conditions, the heat size and reaction speed, and the alloy substitution goal. Larger heats tolerate slower-dissolving coarse material, while small heats benefit from fast-reacting granules. When sourcing, buyers should verify the silicon carbide content and batch consistency, the particle size distribution, the impurity levels of silicon dioxide, iron oxide and alumina, and the moisture content for storage and feeding stability. Certified batch chemistry and packaging suitable for automated feeding or bulk addition reduce operational risk and keep the supply chain smooth.
Frequently Asked Questions
Can Silicon Carbide 88/90 be used in both steel and iron foundries?
Yes. It suits a wide range of metallurgical processes that need a combined silicon and carbon contribution, including electric arc and induction steelmaking, ladle refining and iron foundry melts.
Does particle size influence furnace performance?
Yes. Correct sizing determines dissolution speed and reaction efficiency, so coarse lumps are used for bulk feeding and finer granules for rapid reaction in small heats.
Is 90/92 a better alternative to 88/90?
It depends on the purity requirement. 90/92 offers higher silicon carbide content at a higher cost, while 88/90 is the cost-efficient choice for general metallurgical use.
What impurities matter in Silicon Carbide 88/90?
Silicon dioxide, iron oxide and alumina are the main impurities to check, together with moisture, because they affect slag volume, steel cleanliness and storage stability.
How much ferrosilicon can SiC 88/90 replace?
The substitution ratio depends on the silicon content of the ferrosilicon being replaced, the target chemistry and the process yield. Silicon carbide typically delivers comparable silicon recovery with an added carbon credit, so a trial on the specific furnace is recommended to set the ratio.
What packaging is suitable for SiC 88/90?
Jumbo bags and bulk options suit automated feeding systems, while smaller bags are used for manual dosing, and the packaging should protect against moisture pickup during storage.