The global mining industry is at a crucial crossroads. As concerns about climate change grow and regulatory pressures increase, miners are now evaluated not just by production volumes or profit margins—sustainability has become a core measure of success. China’s “dual - carbon” targets (carbon peaking by 2030, carbon neutrality by 2060) and global ESG (Environmental, Social, Governance) frameworks such as the UN Global Compact and GRI Standards have shifted the focus from “how much can we extract” to “how responsibly can we extract.”
Comminution—the process of reducing ore size through crushing and grinding—is at the heart of this transition. It is the single largest energy consumer in mining operations, and within comminution, grinding circuits are dominant: ball mills alone can account for 40–50% of a concentrator’s total energy use, and in some high - complexity operations, this figure reaches 60%. For reference, a mid - sized copper concentrator processing 50,000 tons of ore per day can consume over 100,000 kWh of electricity daily—with half of that power used for ball mills.
In this context, “sustainable comminution” is no longer a buzzword but a business necessity. Miners face dual pressures: to cut operational costs (energy is often the second - largest expense after labor) and to meet emissions targets. The solution? Reimagining every component of the grinding circuit—starting with the most unremarkable yet critical one: grinding media.
For over a century, steel balls have been the default choice for grinding. Their dominance comes from two key properties: high density (7.8 g/cm³) and impact strength, which make them effective at breaking down hard ores. But in an era of sustainability, their drawbacks can no longer be ignored. Let’s break down the comparison.
Steel balls are typically made from forged or cast steel, with varying carbon contents to adjust hardness. While they work, their lifecycle is full of inefficiencies:
High Energy Consumption
Steel’s high density means ball mills must work harder to rotate them. A 1 - meter - diameter ball mill filled with steel balls requires significantly more motor power than one filled with lighter media. Over time, this leads to higher electricity bills and a larger carbon footprint.
Rapid Wear and Tear
Steel balls wear down through abrasion and impact. In a typical ball mill, steel balls can lose 1–3% of their weight monthly, depending on ore hardness. This wear causes two problems:
Frequent replacements: Mills must be shut down regularly to add new balls, disrupting production.
Contamination: Wear particles (iron oxides) mix with the ore, which can interfere with downstream processes like flotation (e.g., iron contaminants can adsorb onto valuable minerals, reducing recovery rates).
Environmental Costs of Steel Production
Steel manufacturing is energy - intensive. Producing one ton of steel emits 1.8–2.2 tons of CO₂, according to the World Steel Association. For a mine using 1,000 tons of steel balls annually, the embodied carbon from those balls alone is 1,800–2,200 tons of CO₂—before considering the energy used to rotate them.
Contamination Risks
In sensitive applications—such as processing gold ores (where iron can interfere with cyanidation) or battery - grade minerals (like lithium, which requires ultra - pure concentrates)—steel contamination is a major issue. Even trace iron can make a concentrate unmarketable.
Ceramic grinding media is not new, but recent advances in nano - composite technology have transformed its performance. Modern ceramic balls are made from alumina (Al₂O₃) reinforced with nano - sized additives (e.g., zirconia or silicon carbide), creating a material that combines hardness with toughness. Here’s how they compare:
Lower Density, Lower Energy Demand
Ceramic balls have a density of 3.7–4.5 g/cm³—roughly half that of steel. This reduces the “rotational load” on ball mill motors. In practice, this means:
Reduced power consumption: Motors draw less electricity to rotate lighter media.
Less strain on equipment: Lower load extends the lifespan of mill bearings and motors, cutting maintenance costs.
Superior Wear Resistance
Ceramic balls have a surface hardness of 90–95 HRA (Rockwell A), compared to 60–65 HRA for hardened steel. This results in dramatically slower wear: ceramic balls lose only 0.1–0.3% of their weight monthly in most applications. The benefits are:
Fewer replacements: Ceramic balls can last 5–10 times longer than steel balls, reducing downtime.
Minimal contamination: Ceramic wear particles are inert (alumina is non - reactive) and do not interfere with flotation or leaching.
Lower Carbon Footprint
Ceramic production emits far less CO₂ than steel. Producing one ton of nano - composite ceramic balls emits 0.8–1.2 tons of CO₂—less than half of steel’s footprint. When combined with lower energy use during grinding, their total lifecycle emissions are 30–40% lower than steel balls.
Consistency in Downstream Processes
Ceramic’s inertness is a game - changer for mineral recovery. In flotation, for example, iron from steel balls can coat valuable minerals (e.g., copper sulfides), preventing collectors from adhering to them. Ceramic balls eliminate this risk, leading to more stable flotation performance and higher concentrate grades.
Cost Savings Over Time
Ceramic balls have a higher upfront cost (typically 2–3 times that of steel). But their longer lifespan and energy savings offset this. A study by the Chinese Academy of Mining and Technology found that mines switching to ceramic balls saw a 15–20% reduction in total grinding costs (energy + media replacement) within the first year.
| Metric | Steel Balls | Nano - Composite Ceramic Balls | Advantage |
Density | 7.8 g/cm³ | 3.7–4.5 g/cm³ | Ceramic (lower energy load) |
Surface Hardness | 60–65 HRA | 90–95 HRA | Ceramic (wear resistance) |
Monthly Wear Rate | 1–3% of weight | 0.1–0.3% of weight | Ceramic (longer life) |
CO₂ Emissions (Production) | 1.8–2.2 t CO₂/ton | 0.8–1.2 t CO₂/ton | Ceramic (50% lower) |
Energy Use in Mills | Higher (due to density) | 10–25% lower | Ceramic (cost savings) |
Contamination Risk | High (iron oxides) | Low (inert alumina) | Ceramic (stable recovery) |
To understand how ceramic balls perform in real - world conditions, let’s look at a landmark study at a copper recovery plant in China. The plant processes Noranda - type converter slag—a byproduct of copper smelting that contains residual copper (1–3% Cu) worth recovering. Converter slag is notoriously hard to grind, making it a tough test for any grinding media.
The plant’s existing setup used a CSM - 300 vertical mill with steel balls (30 mm diameter) to grind slag to a target fineness of 80% passing 74 μm (required for effective flotation). However, the process had two issues:
High energy consumption: The mill drew 180 kW/h, accounting for 40% of the plant’s total electricity use.
Inconsistent flotation: Iron from steel ball wear was contaminating the slag, leading to fluctuating copper recovery rates (65–72%).
Engineers designed a 12 - week trial to test ceramic balls as a replacement. They used 30 mm nano - composite ceramic balls (density 4.2 g/cm³) and gradually increased their proportion in the mill: 14%, 23%, 30%, and 38% (with steel balls making up the rest). The goal was to measure energy use, flotation performance, and wear rates at each stage.
Experimental Parameters:
Feed rate: 0.6–0.9 t/h (adjusted to maintain throughput)
Mill speed: 750 rpm (standard for the CSM - 300)
Target fineness: 80% passing 74 μm
Flotation test: 5 - minute rougher flotation with xanthate as the collector
The data showed clear trends as the proportion of ceramic balls increased:
Energy Savings
At 14% ceramic balls: Energy use dropped by 5.2% (from 180 kW/h to 170.6 kW/h).
At 23% ceramic balls: Savings rose to 11.4% (159.5 kW/h).
At 30% ceramic balls: Savings reached 16.8% (150 kW/h).
At 38% ceramic balls: Maximum savings of 20.36% (143.4 kW/h).
The reason? Ceramic’s lower density reduced the mill’s rotational load, allowing the motor to draw less power while maintaining the same grinding efficiency.
Flotation Performance
Copper recovery rates stabilized significantly with ceramic balls:
With 100% steel balls: 65–72% recovery (average 68.5%).
With 38% ceramic balls: 71–73% recovery (average 72.1%).
The improvement was due to reduced iron contamination. Lab analysis showed iron levels in the ground slag dropped from 0.8% (with steel balls) to 0.3% (with 38% ceramic balls), allowing flotation collectors to bond more effectively with copper particles.
Wear and Replacement
Over 12 weeks, the steel balls lost 12% of their initial weight (requiring 200 kg of new steel balls to be added). The ceramic balls lost only 1.1% of their weight—no replacements were needed.
The trial showed that ceramic balls can deliver tangible benefits even when mixed with steel balls. For the plant, switching to a 38% ceramic/62% steel mix reduced annual energy costs by ~$45,000 (based on $0.10/kWh) and increased copper recovery by 3.6%, translating to an additional 12 tons of copper recovered annually—worth ~$96,000 at $8,000/ton.
The copper slag study showed promise for partial ceramic use, but what about 100% ceramic balls? To find out, the plant’s R&D team conducted lab - scale tests using a 50 - liter batch ball mill.
Media: 100% 30 mm ceramic balls (density 4.2 g/cm³)
Feed: Noranda converter slag (same as the plant trial)
Target: Achieve 80% passing 74 μm with minimal energy use
100% ceramic balls did achieve the target fineness, but with a note: the feed rate had to be reduced to 80% of the original (0.72 t/h instead of 0.9 t/h). This was because ceramic balls, while hard, have lower impact force than steel (due to lower density). Reducing the feed rate gave them more time to grind the slag, compensating for the lower impact.
Other results were positive:
Energy use: 130 kW/h (27.8% lower than the all - steel baseline).
Flotation recovery: 73.5% (stable, with no iron contamination).
Wear: After 50 hours of grinding, ceramic balls lost only 0.2% of their weight.
The lab trial highlighted a critical principle: ceramic balls excel in applications where impact force is less critical than abrasion resistance. They work best in:
Secondary or tertiary grinding (where ore is already partially reduced, requiring less impact).
Fine regrind circuits (e.g., flotation concentrates, where target fineness is <50 μm).
Mills adapted for ceramic media (e.g., slower speeds or higher filling ratios to compensate for lower density).
For primary grinding (e.g., SAG mills processing run - of - mine ore), steel balls may still be necessary—though hybrid systems (ceramic + steel) can reduce energy use even there.
Switching from steel to ceramic balls isn’t as simple as replacing one media with another. Ceramic’s unique properties require adjustments to mill design and operation. Here’s what engineers need to know.
Density and Load Adjustment
Ceramic balls are 40–50% lighter than steel, so a mill filled with ceramic balls will have a lower total weight. To maintain grinding efficiency, engineers must:
Increase the number of balls: More ceramic balls are needed to match the “grinding surface area” of steel balls. For example, a mill that holds 1 ton of steel balls (≈12,800 balls of 30 mm) will need ~2 tons of ceramic balls (≈23,800 balls of 30 mm) to achieve similar coverage.
Adjust mill speed: In some cases, slightly increasing mill speed (5–10%) can compensate for lower impact force, though this must be balanced to avoid excessive wear on the mill liners.
Mill Filling Ratio
The filling ratio (percentage of mill volume occupied by media) is critical. For steel balls, the optimal ratio is typically 70–75%. For ceramic balls, it’s higher (75–80%) to ensure enough media is in contact with the ore.
Example: A 10 m³ ball mill using steel balls might use 7.5 m³ of media. For ceramic balls, this would increase to 8 m³ to maintain grinding efficiency.
Material Compatibility
Ceramic balls work best with certain ore types:
Oxidized ores (e.g., iron oxide, laterite nickel): These are softer and require more abrasion than impact, playing to ceramic’s strength.
Fine regrind circuits (e.g., flotation concentrates): These require precise fineness, and ceramic’s low contamination ensures downstream processes aren’t disrupted.
They are less ideal for:
Ultra - hard ores (e.g., magnetite with high silica content): These require high impact, where steel still performs better.
Primary grinding (e.g., SAG mill feed): Run - of - mine ore often has large lumps that need breaking, which steel balls handle more effectively.
Mill Design Modifications
Ceramic balls are slightly more brittle than steel (though modern nano - composites are far tougher than older ceramics). They also have smaller diameters (20–50 mm, vs. 50–100 mm for steel in some mills). This means:
Discharge systems: Slotted or grid discharges may need narrower gaps to prevent ceramic balls from leaking. For example, a grid with 25 mm slots used for 50 mm steel balls would need 15 mm slots for 30 mm ceramic balls.
Liner protection: Ceramic balls are harder than steel, so mill liners may wear faster. Using harder liner materials (e.g., high - chrome cast iron) can mitigate this.
Trial Protocols
Before full - scale adoption, engineers should conduct a phased trial:
Lab tests: Verify fineness, energy use, and wear with small batches.
Pilot - scale: Test in a small mill (e.g., 1 m³) with 10–20% ceramic balls, gradually increasing the proportion.
Full - scale: Roll out to one ball mill, monitor for 3–6 months, then expand based on results.
The environmental benefits of ceramic balls go far beyond energy savings in the mill. Let’s quantify their impact on a mine’s carbon footprint.
Scope 2 (energy use): A typical concentrator with 10 ball mills uses ~10,000 MWh/year for grinding. Switching to ceramic balls could cut this by 15–20%, reducing Scope 2 emissions by 3,000–4,000 tons of CO₂/year (assuming 0.5 t CO₂/MWh for grid electricity).
Scope 1 (fuel and on - site emissions): Fewer media replacements mean fewer truck deliveries (for steel balls), cutting diesel use. A mine that replaces 500 tons of steel balls annually could reduce diesel consumption by ~5,000 liters, lowering CO₂ by ~13 tons/year.
As noted earlier, ceramic production emits less CO₂ than steel. For a mine using 1,000 tons of media annually:
Steel balls: 1,800–2,200 tons CO₂ (embodied).
Ceramic balls: 800–1,200 tons CO₂ (embodied).
This is a reduction of 1,000–1,400 tons CO₂/year—equivalent to taking 217–304 cars off the road.
China’s dual - carbon goals require a 65% reduction in carbon intensity (emissions per unit GDP) by 2030. For mining, comminution is an easy area to make changes. Ifcontinue50% of applicable ball mills in China switched to ceramic media, total mining sector emissions could drop by 3–5%—a significant contribution.
Globally, mining accounts for 4–7% of global CO₂ emissions. Adopting ceramic media across 30% of grinding circuits could cut this by 0.5–1%, helping miners meet ESG commitments and attract sustainable investment.
At SANXIN, we’ve spent a decade perfecting ceramic grinding media for mining. Our nano - composite ceramic balls are engineered to address the specific challenges of modern comminution—combining wear resistance, low energy use, and sustainability.
Our ceramic balls are made using a proprietary process:
Raw materials: High - purity alumina (95% Al₂O₃) reinforced with zirconia nanoparticles (0.5–2%), which improve toughness.
Manufacturing: Advanced isostatic pressing and sintering at 1,600°C, creating a dense, uniform structure that resists wear.
Quality control: Each batch undergoes hardness testing (minimum 90 HRA) and impact resistance testing (survives 50 drops from 1 meter onto steel).
We offer ceramic balls in sizes from 20 mm to 50 mm, tailored to different circuits:
| Size | Ideal Application |
20–30 mm | Fine regrind (flotation concentrates) |
30–40 mm | Secondary grinding (ball mills) |
40–50 mm | Hybrid circuits (ceramic + steel mixes) |
Our media is already trusted by leading miners:
Copper concentrators: A Chilean copper mine using 30 mm ceramic balls in secondary grinding reduced energy use by 18% and copper recovery by 2.5%.
Gold tailings recovery: A South African mine processing gold tailings saw 30% lower reagent use after switching to ceramic balls, thanks to reduced contamination.
Iron ore pelletizing: A Chinese iron ore plant using 40 mm ceramic balls in regrind circuits improved pellet strength by 5% (due to more consistent fineness).
We don’t just sell media—we partner with you to ensure success:
On - site trials: Our engineers visit your plant to design trials, adjusting media size and filling ratios for your ore type.
Energy audits: We measure current energy use and project savings with ceramic media, providing a clear ROI timeline.
Process integration: We work with your team to modify mill designs (if needed) and train operators on ceramic media best practices.
The mining industry is at an inflection point. To thrive in a low - carbon world, miners must rethink every aspect of their operations—and grinding media is a critical starting point.
Ceramic balls are not a one - size - fits - all solution, but their benefits—energy savings, lower emissions, reduced contamination, and long lifespan—make them a compelling choice for forward - thinking operations. As the copper slag case study shows, even partial adoption can deliver significant returns.
For grinding circuit engineers, metallurgists, and process managers, the message is clear: the era of “steel - only” grinding is ending. Ceramic media offers a path to meet both sustainability goals and bottom - line targets.
The question isn’t whether to switch to ceramic balls—but when.
Submit your demand,
we will contact you ASAP.
Sanxin New Materials Co., Ltd. focus on producing and selling ceramic beads and parts such as grinding media, blasting beads, bearing ball, structure part, ceramic wear-resistant liners, Nanoparticles Nano Powder
English
English
Russian
French
Spanish
Portuguese
Arabic
