Improving Mining Mill Efficiency with Premium Cast Balls

Ball mills are key equipment in mineral processing and are widely used in copper, gold, iron and other iron ore mines due to their ability to grind fine particles. An inefficient ball mill results in higher costs and lower product quality; on the other hand, a quality and properly operated mill with optimal energy consumption and low maintenance can achieve the desired fineness faster. Therefore, increasing the efficiency and productivity of ball mills is of great importance in the prosperity of mining production. The quality and specifications of grinding balls (metal alloy balls used for grinding in the mill) directly affect the efficiency of the grinding process and energy consumption. Selecting high-quality cast balls and their appropriate heat treatment can reduce ball wear and ensure improved grinding process stability, playing a key role in Improving Mining Mill Efficiency with Premium Cast Balls.

Improving Mining Mill Efficiency with Premium Cast Balls, Challenges of the Study Mine

In this case study, a large mine in Zarqan, which is active in the extraction of a metal ore, was experiencing several problems in its grinding section. Before the project was implemented, the following problems were observed:

• Decreasing ball mill efficiency: The processing efficiency was low and the ratio of mill output to input was constantly decreasing.
• High ball wear: The wear and tear rate of old balls was very high, so that all balls usually needed to be replaced every few months.
• High energy consumption: The specific energy of the mill (kWh per ton of material) was higher than industry standards.
• Frequent shutdowns and high maintenance costs: Breakdowns and unplanned shutdowns for ball replacement and hall repairs increased the mine’s operating costs.

These challenges caused the overall mill unit productivity to decline and production costs to increase.

Solution Provided

To address the aforementioned problems, the technical team replaced the old balls with high-quality cast iron balls manufactured by Sepahan Foolad Atashgah Company. The manufacturer mainly produced the old balls from low-alloy or medium-quality steel, which quickly wore out under severe grinding conditions. The technical team produces the new Sepahan Foolad Atashgah balls from high-chromium cast iron alloy and applies a special heat treatment after production. The important features of the new balls are: high hardness, uniform martensitic microscopic structure with chromium carbides, and very good abrasion resistance. Customers can order these balls in various sizes (diameters from 15 to 125 mm and cylindrical types), and the production team strictly observes quality control standards (chemical analysis, hardness, porosity) during their manufacturing.

New bullet specifications

The new Sepahan Foolad Atashgah cast bullets have the following chemical composition and technical properties:

• Chemical analysis: Contains high chromium (about 10–15% Cr) and resistant elements such as nickel and silicon in controlled amounts. The carbon percentage is also about 2.5–3.5%.
• Mechanical hardness: After quenching and tempering, technicians measure the surface hardness of these bullets between 58 and 66 HRC. Also, the small difference in hardness (maximum 2 HRC) between their surface and core ensures that the bullets maintain a hard and uniform structure up to the core.
• Abrasion performance: Due to the high chromium percentage and optimal heat treatment, these bullets have very high abrasion resistance and low wear rates. In fact, research shows that high chromium bullets increase mill efficiency and reduce energy consumption due to better spherical shape retention (similar to the results of Sailors 1989) while simultaneously lowering the wear rate.
• Life: The long life of these balls means fewer changes in maintenance and replacement intervals. Controlled wear of the balls means fewer purchases and replacement stops. This economic feature reduces the total cost of processing.

Results Obtained

After replacing and operating the new Sepahan Foolad Atashgah cast iron balls, the following results were achieved tangibly:

• Increased mill efficiency: The mill output increased by about 10%, because the energy input was converted into more efficient material grinding. In other words, the mill reached the desired particle size sooner and the input volume efficiency was higher.
• Reduced energy consumption: The mill specific energy (kWh/ton) decreased by about 5%. This was due to improved impact and optimal energy distribution to the particles. The test results seem to confirm that the use of premium grinding media can reduce energy consumption.
• Reduced ball wear rate: Field tests showed that the ball wear rate reached less than 7 grams per ton of material, which is much better than the global standard. In practice, the maintenance team increased the ball replacement interval by about 50% and significantly reduced the number of stops for repair and replacement. The strong and uniform structure of the cast balls enabled this reduction in wear rate.
• Reduced downtime: Operators reduced the number of emergency stops for ball replacement or repairs caused by ball breakage. As a result, they minimized downtime and increased the mill’s useful operating time.

These results resulted in increased productivity and reduced mine operating costs. According to field evidence and industrial studies, a one-year trial period showed that Premium media increased crushing efficiency by 10% and reduced energy consumption by 5% compared to the standard sample, and improved the quality of the final product.

Improving Mining Mill Efficiency with Premium Cast Balls, Economic analysis and return on investment

The choice of new pellets was justified both technically and economically. The analysts calculated the total cost of ownership (TCO) and showed that decision-makers should not base their choice solely on the initial purchase cost; instead, they should also consider the long-term costs of wear, energy consumption, downtime, and repairs. In this study, considering the increased life of the pellets and the reduced energy consumption significantly lowered the cost per ton of material processed.

For example, if we assume the initial cost of each batch of old pellets to be 500 million Tomans and the new pellets to be 750 million Tomans (at the same tonnage scale), but the useful life of the new pellets is 1.5 times longer and the energy consumption is lower, the ROI analysis based on similar examples shows that the initial additional cost is quickly compensated. Industry studies have shown that even with a higher initial cost, a continuous reduction in energy and maintenance costs leads to a rapid return on investment and improved profitability.

Key points of economic analysis: According to a research model, the most important economic factors include the difference in initial cost, wear rate, impact on grinding efficiency, final product quality and energy consumption. Finally, by considering these factors simultaneously and comparing the overall efficiency, investing in high-chromium cast balls became more economically viable than continuing to use the previous worn balls.

Capabilities of Sepahan Foolad Atashgah

With more than 30 years of brilliant experience in the field of industrial casting, Sepahan Foolad Atashgah Company has high production capacity and quality control. With 7 induction furnaces with a capacity of 20 tons each and a production area of 25,000 square meters, the company produces about 25,000 tons of castings annually. Specialized manpower (more than 250 people) and advanced laboratory equipment guarantee high quality products. Among the honors of this company are cooperation with the steel, copper, mining and cement industries; so that it supplies sensitive parts such as AG/SAG mill liners, pelletizing diaphragms, anti-wear coatings and anti-wear cast balls, contributing to Improving Mining Mill Efficiency with Premium Cast Balls.

In the mill ball section, Sepahan Foolad Atashgah produces various types of high-hardness chromium cast irons according to the standards of various customers, using modern technical knowledge and precise heat treatment. This capability has made the company’s cast balls, with their abrasion resistance and very high useful life, competitive in the country’s mining industries. For example, Sepahan Foolad Atashgah has a history of providing casting solutions to large copper and steel mines, and its export resume indicates the market’s trust in the quality of its products, further emphasizing their role in Improving Mining Mill Efficiency with Premium Cast Balls.

Conclusion and invitation to cooperation

The above case study showed that the use of quality cast balls produced by Sepahan Foolad Atashgah has significantly increased the efficiency of the mine ball mill, reduced energy consumption, reduced the ball wear rate, and as a result, improved the economy of the crushing process. These results are in line with scientific and industrial studies that indicate that high chromium grinding media has a longer life and better efficiency. Sepahan Foolad Atashgah is ready to provide a sustainable solution to increase your productivity and reduce your costs by supplying high-quality grinding balls for copper, gold, iron, lead, zinc and other mines. For more information and to order high-quality cast balls, you can contact the company’s technical team and benefit from the specialized advice of the Commercial Manager.