The cement industry is continuously evolving, driven by the dual demands of increasing production efficiency and reducing environmental impact. One of the most significant advancements in this field has been the adoption of co-grinding systems for clinker and slag. This process involves grinding granulated blast furnace slag (GBFS) together with Portland cement clinker, resulting in a superior blended cement product. At the heart of these modern co-grinding systems lies the Vertical Roller Mill (VRM), a technology that has revolutionized grinding operations with its exceptional efficiency and performance. Shanghai Zenith Machinery Co., Ltd., a leader in the field of industrial grinding equipment, has made remarkable contributions to this technology.
Co-grinding clinker and slag offers numerous technical, economic, and environmental benefits. Slag, a by-product of the steel industry, possesses latent hydraulic properties. When finely ground and in the presence of activators like clinker, it develops excellent cementitious properties. Blended cements produced through co-grinding exhibit enhanced durability, lower heat of hydration, and superior resistance to chemical attacks compared to ordinary Portland cement.
From an environmental perspective, utilizing slag reduces the clinker factor—the proportion of clinker in cement. Since clinker production is the most energy-intensive and CO2-emitting part of cement manufacturing, reducing its use directly lowers the carbon footprint of the final product. This makes co-grinding a cornerstone of sustainable cement production.
Traditional ball mills have been the workhorses of the cement industry for decades. However, for co-grinding applications, Vertical Roller Mills offer distinct advantages that make them the preferred choice:
Successfully operating a co-grinding system requires careful attention to several factors. The differing grindability of clinker (harder) and slag (less hard but tougher) must be managed to achieve a homogeneous blend. The feed ratio of clinker to slag is critical and must be controlled precisely. Furthermore, the moisture content of the slag dictates the required drying capacity of the mill system. Modern VRMs from manufacturers like Shanghai Zenith are equipped with sophisticated control systems that automatically adjust operational parameters to maintain consistent product quality despite variations in feed material.
Shanghai Zenith Machinery Co., Ltd. has established itself as an excellent manufacturer of ore and mineral grinding equipment, with extensive expertise in ultra-fine powder grinding. Their research and development focus on creating robust, efficient, and intelligent grinding solutions tailored to the specific needs of the cement and mining industries. For clinker and slag co-grinding applications, two of their flagship products stand out: the LM Vertical Grinding Mill and the LUM Ultrafine Vertical Mill.
The LM Vertical Grinding Mill is a highly integrated machine that combines crushing, grinding, powder selection, drying, and material conveying into a single unit. Its design philosophy emphasizes high output, low energy consumption, and long-term reliability, making it perfectly suited for large-scale cement plants engaged in co-grinding.
For co-grinding clinker and slag, the LM Vertical Slag Mill series is particularly relevant. These mills are engineered to handle the abrasive nature of slag while maintaining high grinding efficiency. The robust construction of the grinding rollers and table, along with advanced material technology, ensures extended service life and reduced maintenance downtime.
The following table details the technical parameters of the LM Vertical Slag Mill series, which is highly recommended for dedicated or co-grinding slag applications:
| Model | Capacity (t/h) | Main Motor (kW) |
|---|---|---|
| LM130N | 4-6 | 200-250 |
| LM220N | 20-26 | 900-1000 |
| LM370N | 90-110 | 3150-3300 |
When the production target is ultra-fine blended cement with superior early and late-age strength, the LUM Ultrafine Vertical Mill is the ideal solution. This mill represents the cutting edge of grinding technology, integrating ultra-fine grinding, classification, and transportation with minimal space requirements.
The LUM series features a unique roller and ring design that creates a higher pressure grinding zone, enabling it to achieve fineness levels up to 5-30 microns (D97). Its intelligent control system allows for precise adjustment of grinding force and classifier speed, ensuring a consistent and optimal product quality for high-value cement blends. This mill is perfect for producers aiming to maximize the reactivity of slag in their final product.
| Model | Main Machine Power (kW) | Capacity (t/h) | Size Distribution D97 (μm) |
|---|---|---|---|
| LUM1525 | 220-250 | 1.6-11.5 | 5-30 |
| LUM1632 | 280-315 | 2.0-13.5 | 5-30 |
| LUM1836 | 355-400 | 2.3-15 | 5-30 |
The shift towards clinker and slag co-grinding is a definitive trend in the global cement industry, aligning economic goals with environmental responsibility. The Vertical Roller Mill has proven to be the most capable technology for this demanding application, offering unparalleled efficiency, flexibility, and control. Shanghai Zenith Machinery Co., Ltd., with its comprehensive portfolio of advanced grinding mills like the LM and LUM series, provides reliable and high-performance solutions tailored to the specific needs of modern co-grinding systems. By partnering with an experienced manufacturer like Zenith, cement producers can optimize their operations, reduce their environmental impact, and produce high-quality blended cements for the future.
