What unique impacts does the hard physical property of industrial silicon have on the production process of silicon-aluminum alloys?
Publish Time: 2025-12-05
As a key raw material with a silicon content of no less than 98%, industrial silicon is widely used in the production of silicon-aluminum alloys, organosilicon, and new energy materials. One of its significant physical properties—its hardness—while not directly participating in chemical reactions during the smelting of silicon-aluminum alloys, has a profound and unique impact on the entire production process. This impact extends to multiple stages, including raw material pretreatment, smelting, equipment maintenance, and even final product quality control.1. Challenges of Raw Material Crushing and Particle Size ControlIndustrial silicon is usually shipped in lumps, but due to its extremely high hardness, conventional crushing equipment is difficult to process efficiently and easily causes equipment wear. If the crushed particles are too large, they are difficult to dissolve quickly when fed into the aluminum molten furnace, easily settling to form unmelted particles, leading to uneven composition. If the particles are too fine, the specific surface area increases, making it easy to oxidize at high temperatures, generating silica dust, which not only causes silicon loss but may also pollute the environment and affect alloy purity. Therefore, precise control of the particle size distribution of industrial silicon is essential before smelting. This places higher demands on crushing processes and screening systems, and increases pretreatment costs.2. Slow Melting Rate and Increased Energy ConsumptionAlthough the melting temperature of silicon-aluminum alloys is typically maintained between 700–800℃, pure silicon has a melting point as high as 1414℃. This means that industrial silicon does not "melt" in molten aluminum, but rather gradually "dissolves" and diffuses in the form of solid particles. Its hard and dense crystal structure results in low thermal conductivity, leading to a slow and uneven dissolution process, especially pronounced in high-silicon content alloys (such as Al-12Si or Al-20Si). To accelerate dissolution, factories often adopt measures such as increasing furnace temperature, extending holding time, or strengthening stirring. While these methods are effective, they significantly increase energy consumption and may exacerbate metal burn-off, affecting the overall economic efficiency of smelting.3. Increased Equipment Wear and Maintenance CostsDuring smelting and stirring, undissolved industrial silicon particles act like high-hardness abrasives, continuously eroding critical components such as the furnace lining, stirring paddle, and discharge port under the influence of flowing aluminum liquid or mechanical/electromagnetic stirring. Over long-term operation, refractory materials or metal parts are prone to scratches, peeling, and even perforation, not only shortening equipment lifespan but also potentially introducing impurities such as iron and chromium, reducing alloy quality. Therefore, high-end production lines generally employ ceramic linings, silicon carbide coatings, or special wear-resistant alloy components, significantly increasing equipment investment and maintenance costs.4. Dual Impact on Alloy QualityIt is worth noting that the hardness of industrial silicon is not entirely negative. Its dense structure means lower porosity and specific surface area, helping to reduce oxidation loss at high temperatures, thereby improving the actual yield of silicon. Simultaneously, the high hardness of bulk silicon makes it less prone to pulverization during transportation and storage, ensuring the stability of the raw material composition and providing a reliable basis for the precise proportioning of subsequent alloy components.The hardness of industrial silicon is a double-edged sword: on the one hand, it presents technological challenges such as difficulty in crushing, slow melting, high energy consumption, and significant equipment wear; on the other hand, its stable structure facilitates composition control and improved yield. Modern silicon-aluminum alloy smelting technology is cleverly mitigating its negative impacts and fully leveraging its value as a core raw material by optimizing particle size distribution, developing efficient stirring systems, applying intelligent temperature control strategies, and upgrading wear-resistant materials. A deep understanding and adaptation to the physical properties of industrial silicon is key to achieving efficient, energy-saving, and high-quality silicon-aluminum alloy production.
