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Silicon slag is a valuable industrial by-product generated during the smelting of metallic silicon. Primarily composed of silicon dioxide (SiO₂) and carbon (C), with minimal metallic impurities, it has become a widely adopted, economical material across multiple sectors—especially in metallurgical applications where cost efficiency is key.
Silicon slag is characterised by its significant residual silicon and high carbon content. While specific compositions can vary based on the source smelting process, it generally contains usable silicon content along with carbon, making them suitable for certain alloying and reducing agent roles where pure metallic silicon is not required.
Important Note: Silicon slag is not a direct substitute for metallic silicon in precision applications. A practical foundry test demonstrated that replacing 30% of metallic silicon with silicon slag in aluminium alloy production led to increased porosity in castings, causing an approximate 18% drop in product yield. This is largely due to the high carbon content and gaseous impurities in the slag, which can adversely affect metal quality in sensitive processes.
High Carbon Content: Results from excess coke used during the original smelting process, where unreacted carbon combines with silicon oxides.
Porous Structure: The material forms loose, granular particles upon cooling, which makes it prone to absorbing moisture from the air.
Combustion Risk: The carbon content can undergo slow oxidation when stored in bulk, potentially leading to heat accumulation and a risk of spontaneous combustion in large, unventilated piles. Proper storage in dry, cool, and well-ventilated areas is essential.
Due to its composition, silicon slag is effectively used as:
A cost-effective additive in steelmaking for minor silicon recovery and as a reducing agent.
A substitute for more expensive ferrosilicon in certain foundry and ferroalloy production processes where exact silicon specifications are less critical.
A raw material in the manufacturing of silicon briquettes and other aggregated alloys.
Silicon slag is collected from metallic silicon furnaces, where unreacted silica and carbon residues are separated. It is then processed—crushed, screened, and sometimes briquetted—into specified sizes (powder, granules, or balls) as required by end-users.
As an economical alternative, it is priced significantly lower than ferrosilicon or metallic silicon. In markets like Tianjin, China, the average price is approximately $500 per ton, fluctuating based on the precise silicon and iron content.
Quality-Assured Supply: We provide consistent silicon slag, with products backed by SGS certification for transparent composition analysis.
Factory-Direct Pricing: Eliminating intermediaries allows us to offer you the most competitive prices directly from our production line.
Sample Policy: We offer free samples (approx. 1kg) for quality verification (customer covers shipping).
Efficient Logistics: With extensive export experience, we ensure production and preparation are typically completed within 7 to 15 working days.
Flexible Commerce: We accept secure payment methods including T/T (Telegraphic Transfer) and L/C (Letter of Credit).
For industries where cost-saving is prioritised without compromising on basic metallurgical function, Hongshun Ferroalloy’s silicon slag offers a reliable and economical solution. Contact us today for specifications, pricing, or to request your sample.
