**Editor's Note**: In China, where the mechanical processing, defense, and metallurgical industries are growing rapidly, corundum and silicon carbide play an irreplaceable role as abrasives and refractories, holding significant strategic value. However, with today’s severe overcapacity, the industry is facing a critical choice between survival and development. The three major challenges—energy consumption (comprehensive utilization), raw material supply, and environmental protection—are key to breaking through the current difficulties. Among these, environmental protection has become the top priority.
In the 1960s, most abrasive enterprises were small or micro-scale, operated under local industrial bureaus, and enjoyed good economic performance. As the national economy developed and the economic system evolved, the industry underwent major changes. Production capacity and output increased dramatically, but production methods, techniques, and equipment have seen little advancement. Corundum and silicon carbide are still smelted in traditional furnaces such as dump, fixed, and resistance types. Domestic grinding wheels cannot yet match high-speed, high-efficiency foreign alternatives, and most production remains semi-mechanized. Now, rising labor costs and declining profits in large-scale workshop-style operations have led to serious issues. Severe pollution not only makes it hard to attract workers, but also causes public concern due to smog and dust emissions. Therefore, the abrasive (refractory) industry must prioritize technological innovation and environmental protection.
Based on long-term experience in the abrasive industry, several views are proposed:
**1. Environmental regulations for the abrasive industry should be reasonable and not too strict or too lenient.**
The national standard for indoor emissions is 10mg/m³, which allows workers to leave the workshop without soiling their clothes or shoes after an 8-hour shift. The outdoor emission standard of 30mg/m³ is commonly used in the metallurgical industry, making chimney emissions invisible to the naked eye. While this standard is not overly strict, achieving it requires significant investment, sometimes even exceeding the cost of major equipment. This standard is merely the minimum for human survival. As living standards improve, stricter regulations are inevitable. The World Health Organization currently sets air dust emission limits at 50μg/m³, which is 1/600th of the current outdoor standard. Since the sky is a shared resource, emissions will inevitably be further tightened. If the abrasive industry faces stricter environmental rules, companies must balance the feasibility of technical solutions with their ability to invest.
**2. Boldly eliminate outdated granulation methods and adopt advanced technologies like clear-blowing.**
Traditional pickling and washing methods, which rely on source-side dust removal, are being replaced by clear-blowing technology—a method first introduced in China and widely used in advanced countries like the U.S. Many design institutes have stopped working on pickling and washing lines, signaling progress. With the government pushing for dust control at the source, dust is removed during its generation rather than later. For example, dust from crushing is captured immediately, preventing it from spreading during screening. This approach significantly improves environmental conditions.
**3. Reassess traditional dust removal methods based on current needs.**
Water curtains and electrostatic precipitators were once effective for enterprises without dust control systems, but they now lack efficiency and cannot meet modern emission standards. To achieve 10mg/m³, purification efficiency must exceed 95%. Bag filters and cartridge dust collectors are the current options. While bag filters work well at around 250°C, cartridge dust collectors function best below 110°C and require cooling for higher temperatures. Despite this, cartridge dust collectors are gaining popularity globally due to their compact design, long lifespan, and ease of maintenance.
**4. Dust-free systems must be carefully designed to ensure practicality.**
From initial inspection to real-world application, proper system design is essential. Dust removal is a complete system, influenced not just by the equipment itself, but also by pipeline resistance and the placement of collection hoods. Without careful on-site planning, even the best equipment may fail. High-temperature dust removal, for instance, requires reducing flue gas temperature from around 500°C to below 120°C, often using natural or forced cooling. These processes can impact the dust removal system’s performance. Unfortunately, many companies cut costs by building inadequate systems, leading to failure down the line.
**5. Comprehensive utilization of waste materials is crucial.**
Many enterprises have already started recovering carbon monoxide from silicon carbide smelting waste gas. Corundum smelting waste heat is also being utilized. The recovery of dust collected during smelting and granulation is still under study, but promising results are expected.
**6. Industry-wide environmental challenges remain.**
The loading and unloading of silicon carbide smelting involves poor environmental conditions. Achieving clean production is a common concern, and solutions must be economically feasible.
**Conclusion**: The abrasive industry is currently undergoing a tough test in the broader context of national environmental reforms. Entrepreneurs now recognize its importance, and environmental compliance has become a prerequisite for survival and growth. The only way forward is to apply existing mature technologies while continuously innovating and improving processes, ensuring that abrasive production becomes truly clean, efficient, and intelligent.
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