Nickel Slag Powder Production Line Process and Equipment Configuration

Introduction

The comprehensive utilization of nickel slag, a by-product of nickel smelting, has gained significant attention in the industrial sector due to its potential as a supplementary cementitious material and for other value-added applications. Processing this hard, abrasive material into fine powder requires a robust, efficient, and well-configured production line. This article details the complete process flow and optimal equipment configuration for a modern nickel slag powder production line, highlighting key technological considerations and equipment selection to maximize productivity and product quality.

Characteristics of Nickel Slag and Processing Challenges

Nickel slag possesses several inherent properties that present challenges for grinding:

• High Hardness and Abrasiveness: Nickel slag typically has a Mohs hardness between 6-8, leading to rapid wear on grinding components.
• Variable Composition: Its chemical and mineralogical composition can vary, affecting grindability.
• Moisture Content: Slag from certain processes may contain moisture, requiring pre-drying.
• Target Fineness: For use in cement and concrete, a high Blaine fineness (e.g., ≥420 m²/kg) is often required, demanding precise grinding and classification.

These challenges necessitate the selection of equipment specifically designed for durability, high efficiency, and precise particle size control.

Nickel Slag Powder Production Line Process Flow

A standard production line can be broken down into several key stages:

1. Raw Material Pre-Treatment and Feeding

Nickel slag is first transported from the stockpile. If the moisture content is high (>1%), a dryer (e.g., a rotary dryer) may be integrated into the line. A vibrating feeder, such as the GZ series mentioned in our equipment specs, ensures a steady and controlled feed rate to the subsequent crushing stage.

2. Primary and Secondary Crushing

The slag, often with a feed size up to 50mm, must be reduced to a finer granularity suitable for the grinding mill. A two-stage crushing system is common:

• Primary Crushing: A jaw crusher (e.g., PE series) reduces the slag to below 100mm.
• Secondary Crushing: For further size reduction to below 30-50mm, a hammer crusher or impact crusher is highly effective. Our PC Series Hammer Crusher is an excellent choice for this duty. Its high-speed rotating hammers and robust, high-manganese steel liners are designed to handle abrasive materials efficiently, producing a consistent output of 0-3mm to 0-8mm, which is ideal for feed to grinding mills.

3. Grinding and Classification: The Core of the Process

This is the most critical stage, determining the final product’s quality and energy consumption. Vertical roller mills (VRMs) have become the industry standard for slag grinding due to their superior energy efficiency compared to traditional ball mills.

Our LM Vertical Slag Mill Series (e.g., LM130N to LM370N) is specifically engineered for this application. The process within the mill involves:

• Feed Introduction: Pre-crushed slag is fed onto the center of the rotating grinding table.
• Grinding: Hydraulically loaded grinding rollers exert pressure on the material bed, causing inter-particle comminution.
• Drying: Hot gas (from a hot air generator) introduced under the table dries the material while carrying the fines upward.
• Classification: An integrated dynamic classifier immediately above the grinding zone separates the fine product from coarse particles. The coarse material falls back onto the table for further grinding.

The key advantages of the LM Slag Mill for nickel slag include:

• High Efficiency & Low Energy Consumption: Utilizes the efficient bed-breaking principle, reducing energy use by 30-40% versus ball mills.
• Integrated Drying and Grinding: Handles slag with moisture content up to 15%.
• Precise Particle Size Control: The dynamic classifier ensures a consistent product with the required specific surface area (≥420 m²/kg).
• High Availability and Low Wear: Modular design allows for quick roller replacement, and wear parts are made from highly abrasion-resistant materials.

4. Product Collection and Storage

The fine powder leaving the classifier is transported by air to the product collection system. This typically consists of a high-efficiency baghouse dust collector (pulse jet type). Our mills are equipped with advanced pulse-jet bag filters that ensure dust emissions are kept well below international standards (<20 mg/m³). The collected nickel slag powder is then conveyed via screw conveyors and bucket elevators to large storage silos, ready for packaging or bulk shipment.

5. Auxiliary Systems

A complete line also relies on several auxiliary systems:

• Hot Air Generation: A gas, oil, or coal-fired hot air generator provides the necessary heat for drying.
• Electrical and Automation Control: A central PLC-based control system monitors and optimizes the entire process, from feed rate to mill load and product fineness, ensuring stable and unmanned operation.

Equipment Configuration Recommendations

Selecting the right model depends on the required production capacity. Here are two typical configurations based on our equipment:

Configuration for Medium Capacity (e.g., 10-12 t/h)

• Secondary Crushing: PC4012-90 Hammer Crusher (15-40 t/h capacity)
• Grinding Mill: LM190N Vertical Slag Mill (10-12 t/h capacity, 500-560 kW main motor)
• Dust Collection: Pulse Baghouse Dust Collector
• Feeding & Conveying: GZ4F Vibrating Feeder, Belt Conveyors, Bucket Elevators

Configuration for High Capacity (e.g., 50-60 t/h)

• Secondary Crushing: Two units of PC4015-132 Hammer Crusher or a larger impact crusher.
• Grinding Mill: LM280N Vertical Slag Mill (50-60 t/h capacity, 1800-2000 kW main motor)
• Dust Collection: Large central Pulse Baghouse Dust Collector
• Feeding & Conveying: High-capacity feeders and conveyors.

Conclusion

Establishing an efficient and profitable nickel slag powder production line hinges on a deep understanding of the material’s properties and the selection of robust, energy-efficient equipment. The process flow from crushing to grinding and collection must be seamlessly integrated. The use of specialized technology, such as our LM Vertical Slag Mill series, is critical to achieving the desired product quality with minimal operational costs. By leveraging advanced grinding principles, intelligent control systems, and durable component design, producers can successfully transform nickel slag from an industrial waste into a valuable commodity, contributing to both economic and environmental sustainability.