Metallic Silicon 553 (also named Si553 industrial silicon) is one of the most mainstream general-grade industrial silicon products. The grade code "553" stands for Fe ≤0.5%, Al ≤0.5%, Ca ≤0.3%, with the minimum silicon content reaching 98.5%.

Produced via high-temperature smelting of silica and carbon-based reducing agents in submerged arc furnaces, it features balanced purity and cost performance. Compared with ultra-high purity grades like Silicon3303 and Silicon2202, Silicon metal 553 has obvious price advantages while meeting the requirements of most conventional industrial scenarios. It is widely applied in aluminum alloy manufacturing, organosilicon synthesis, steelmaking deoxidation and refractory production, becoming a cost-effective basic raw material for global industrial manufacturing.

metallic si 553

chemical composition

Silicon Metal	Grade	Chemical Composition
		Si(%)	Impurity Content
		Si(%)	Fe(%)	Al(%)	Ca(%)	P(PPM)
	97	>97.0%	≤1.5	≤0.5	≤0.3
	553	>98.5%	≤0.5	≤0.5	≤0.3	-
	441	>99.0%	≤0.4	≤0.4	≤0.1
	3303	>99.3%	≤0.3	≤0.3	≤0.03	≤50
	2502	>99.5%	≤0.25	≤0.25	≤0.02	≤40
	2202	>99.5%	≤0.2	≤0.2	≤0.02	≤40
	421	>99.2%	≤0.4	≤0.2	≤0.1	-
	411	>99.2%	≤0.4	≤0.1	≤0.1	-

Available Sizes: 0~1mm, 1~3mm, 10mm~50mm, 10~60mm, 10~100mm, customized particle sizes are supported.

Standard Packaging: 1-ton moisture-proof woven bag with pallet loading; customized sealed bags and drums for export orders.

Storage Requirements: Store in dry and ventilated warehouse. Keep away from rain, moisture and corrosive gas to prevent surface oxidation and performance decline.

Application field

Aluminum alloy production

Si553 is the primary additive for ordinary cast aluminum and architectural aluminum profiles. It can improve the fluidity of molten aluminum, enhance the hardness, wear resistance and corrosion resistance of finished products. Widely used in building profiles, daily hardware, and ordinary automotive aluminum parts.

Polysilicon production

As the basic raw material for silicone oil, silicone rubber, sealants and other organosilicon products. It reacts with methyl chloride and other reagents under catalysts. Suitable for conventional civil and industrial organosilicon production, with qualified impurity content that will not cause catalyst poisoning.

Organosilicon synthesis

Used as deoxidizer and alloy additive in carbon steel and low-alloy steel production. It removes dissolved oxygen in molten steel, reduces pores and oxide inclusions, and improves the tensile strength and yield strength of steel products. Also used for manufacturing silicon steel sheets.

Refractory manufacturing

With a high melting point and excellent thermal stability, it is added to high-temperature refractory bricks and kiln linings to improve slag corrosion resistance and prolong the service life of industrial kilns.

Steel industry

After primary purification treatment, it can be used as the raw material for conventional polysilicon, matching the production needs of ordinary solar cell components.

Core Physical Properties & Advantages

Stable Composition: Strict furnace smelting control, small batch-to-batch fluctuation, stable reaction effect in continuous production.

Moderate Impurity Matching: Fe/Al/Ca indicators are tailored for conventional industries, avoiding excessive slag in aluminum alloy and steelmaking processes.

Excellent Dissolution Performance: Regular lump/particle structure, fast melting speed and high absorption rate in molten metal.

High Cost Performance: Balanced purity and price, the preferred choice for large-volume procurement of general industrial projects.

Diversified Specifications: Multiple particle sizes adapt to different furnace types and automatic batching systems.

FAQ

Q1: What does the grade 553 mean for metallic silicon?

A: The code 553 represents Fe ≤0.5%, Al ≤0.5%, Ca ≤0.3%, and the silicon content is no less than 98.5%.

Q2: What is the main difference between Si553 and Si441?

A: Si441 has lower Ca and Fe content, suitable for high-end aluminum alloy and high-purity organosilicon. Si553 has higher cost performance and is more suitable for mass production of conventional industries.

Q3: What industries is Si553 mainly used for?

A: It is widely used in ordinary aluminum alloy, organosilicon synthesis, steelmaking deoxidation and refractory material production.

Q4: Can you provide samples and customized sizes? What is the delivery time?

A: Free test samples are available. Standard in-stock goods are delivered within 7–15 working days; customized products take 20–30 working days.

Q5: What is the MOQ and payment term?

A: The minimum order quantity is 25 tons or one full container. We support T/T and L/C payment terms.

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