Vertical roller mill

The particle size distribution of the nickel slag vertical mill's product is relatively concentrated, with a typical D90/D10 ratio ranging from 2.5 to 3.5. For example, when the target fineness of the product is 200 mesh, approximately 80% of the product particles are between 45-75 microns, with 10% smaller than 45 microns and 10% larger than 75 microns.

The efficient classification system of the vertical mill ensures the uniformity of product particle size, which is beneficial for the stability of subsequent processing. Compared to ball mills, the vertical mill has a narrower product particle size distribution, which helps improve product quality.

The nickel slag vertical mill can adapt to various nickel slags with a Mohs hardness of 2-7. For example, for ordinary nickel slag with a hardness of 4-5, the grinding roller pressure is set at 800-1000 kN; whereas for high-hardness nickel slag with a hardness of 6-7, the pressure can be increased to 1200-1500 kN.

The vertical mill can flexibly respond to different hardness levels of nickel slag by adjusting the grinding roller pressure and speed, maintaining a stable capacity of 80-100 tons per hour. The adaptability of the vertical mill to hardness variations is stronger, keeping production capacity fluctuations within ±10%.

When processing high magnesium nickel slag (with MgO content >25%), the following points should be noted:
1) Control the feed particle size to be below 10-15 mm to prevent roller clogging;
2) Increase the roller pressure to 1000-1200 kN to overcome the toughness of magnesium silicate minerals;
3) Properly increase the classifier speed, typically to 150-180 rpm, to ensure sufficient grinding fineness;
4) Control the internal temperature of the mill to 90-110°C to prevent the softening of magnesium silicate minerals.
By taking these measures, the processing capacity of high magnesium nickel slag can be maintained at 80-85% of normal levels.

Clay minerals in nickel slag can affect the performance of the vertical mill, requiring corresponding measures. For instance, when the clay content in nickel slag reaches 15-20%, the internal temperature of the mill should be controlled at 100-120°C to reduce the viscosity of the clay.

At the same time, adding 1-2% of a dispersant, such as water glass, can help prevent material agglomeration. Additionally, it is recommended to increase the classifier speed by 10-15%, typically to 170-190 rpm, to improve classification efficiency.

These measures can help control the impact of clay on production capacity to within 10%, ensuring stable production.

Nickel slag is a byproduct generated during the nickel smelting process. During high-temperature smelting and complex chemical reactions, nickel is extracted from the ore, leaving behind waste residue known as nickel slag.

The composition of nickel slag mainly includes silicates (40-60%), iron oxides (20-40%), aluminum oxides (5-10%), and small amounts of other metal oxides. Physically, nickel slag typically appears as dark gray or black bulk or granular material, characterized by high hardness and wear resistance, with a density generally ranging from 2.5 to 3.5 g/cm³.

Unprocessed nickel slag can cause serious environmental pollution, such as occupying large land resources and posing potential heavy metal contamination to water sources. Therefore, the effective treatment and reuse of nickel slag are not only necessary for resource recovery but also an essential requirement for environmental protection.

Building Materials: Ground nickel slag powder can be used as an additive in cement and concrete, significantly improving the strength and durability of building materials. For example, adding 10-20% nickel slag powder can increase the compressive strength of concrete by 15-20%.

Road Construction: Nickel slag powder can be used as a base material and filling material in road construction, providing good stability and durability. Using nickel slag as a filler can reduce subsidence in the roadbed and extend the lifespan of the road.

Soil Improvement: A small amount of nickel slag powder can be used to improve soil structure, enhancing soil aeration and water retention. For instance, adding 5-10% nickel slag powder to poor soil can significantly improve its physical properties.

Eco-Friendly Materials: Nickel slag can be used to manufacture eco-friendly bricks and other building products, replacing some natural materials, thereby reducing resource consumption and environmental damage. Bricks made from nickel slag exhibit better compressive strength and durability compared to traditional bricks.