Chemical grinding aids are quietly cutting energy bills and mechanical wear in mills — and the maintenance math is compelling.
Cement grinding is a brutal business: globally, producers burn through roughly 110–120 kWh per tonne of cement, with about 40–70% of that in the finish‑grind mills (kilowatt‑hours per tonne, a standard specific‑energy metric) (NBMCW; IntechOpen).
Inside those mills, hard clinker hammers steel liners and balls. Wear comes via impact, abrasion, attrition, and cyclic fatigue — and in wet mills, corrosion adds another failure mode (911Metallurgist). In practice, a large share of liners and media — often more than 25% of new weight — is discarded as worn‑out waste (911Metallurgist).
That matters in the P&L. Even a 5 kWh/t drop at a 1 Mt/yr plant saves ~5 GWh (≈$250k/yr) and eases strain on the equipment. And it’s where an unglamorous tool — chemical grinding aids — is making a measurable dent.
How grinding aids change the physics
Grinding aids are small‑dose process additives that adsorb onto fresh clinker surfaces, neutralize electrostatic charges, and lay down thin films that stop fine particles from sticking or agglomerating (i.e., clumping) (SCiELO; NBMCW).
By lowering interparticle cohesion and friction, the mill charge becomes more fluid and receptive to impact. Sika notes grinding aids “reduce the attraction force of finely‑ground cement particles and avoid agglomeration,” which increases separator and mill efficiency and raises powder fluidity (Sika). Less “packing” of fines around bigger grains means smoother circulation and fewer separator rejects, translating to a faster breakage rate at unchanged mill speed and media load.
Throughput and energy: the measured gains
In lab and plant trials, the gains are consistent. Reports cite 5–15+% higher throughput or faster grind at the same power input (911Metallurgist; Sika VRM trial), with industrial tests showing 9–15% ball‑mill production increases without raising power draw (911Metallurgist). In a vertical‑roller mill (VRM, a mill using a rotating table and rollers) trial, 0.05% of a modern aid lifted production ~+11% and cut specific energy by 8–10% (Sika VRM trial).
Zan et al. (2023) found the best aid reduced the energy needed for a target Blaine (Blaine is a specific surface area measure of cement fineness) and increased the prevalence of fine particles (SCiELO; SCiELO). Literature cites 15–25% efficiency improvements under optimal conditions (SCiELO). For a 1 Mt plant, even a 10% throughput gain implies ∼100 kt more cement/year.
On energy, one published VRM trial (Table 2) dropped demand from 38.0 to 34.2 kWh/t (∼−10%) while output rose ~+11% (Sika VRM trial). More broadly, “the use of grinding aids is an effective way to improve production and fineness as well as reduce energy consumption and costs” (SCiELO). A wider particle‑size distribution (PSD) tends to hydrate more uniformly, improving early and 28‑day strengths — a useful side benefit (SCiELO; SCiELO).
Operationally, maintenance teams see steadier load profiles and lower power peaks. With fewer agglomerates, the separator can handle slightly higher mass flow without a pressure surge, and the fresh feed rate can increase. Sika reports that in VRM tests the additive “reduced ΔP_mill” (pressure drop across the mill) and increased production (Sika).
Cleaner internals, less abrasive wear
A critical benefit: cleaner internals. In normal operation, very fine cement adheres to liners and balls, forming a dense “cake.” That uneven, brittle layer makes subsequent impacts harsher — often cement‑on‑metal rather than clean metal‑on‑metal. Aid molecules that neutralize particle charges reduce coating of the mill surface and steel balls; imaging showed far less cement smearing on emerald balls when aid was used (SCiELO).
Cleaner balls mean more elastic, uniform impacts; liners see lower point loads. In vertical mills, appropriate aids deliver “reduced vibration, [and] less wear” on the roll table (Sika). Dr. Das similarly reports optimized dosing “reduces agglomeration of particles on the balls & liners in the mill” (NBMCW).
Scale it up and the consumables bill is huge: one industry engineer calculated ∼83,000 t of balls per 1 Mt of annual cement capacity (∼83 kg per tonne of cement) (slideum.com). If aids trim wear by 10%, that’s 8–10 kg less media per tonne — several dollars saved per tonne at prevailing steel prices — and liner plates last longer (hundreds of tons of consumables can be saved annually across a plant, per the same source) (slideum.com).
The maintenance dividend is fewer shutdowns for liner changes or cleaning. Reduced coating curbs pack‑set (a tendency for powder to compact and stick) and “sticking,” so silos, feeders, and chutes bridge less. The operational life of each liner segment or ball size class increases. The overall outcome is lower cost per tonne of cement.
Quantified improvements and adoption
Typical trials show +5–15% output at unchanged power (911Metallurgist; Sika VRM trial). In one VRM case, 0.05% aid boosted production +11% while cutting energy per tonne ≈10% (Sika VRM trial). Even a +5% daily lift compounds to thousands of extra tonnes per year (with corresponding savings on crusher‑cycle energy).
Because circulation improves, specific power can fall: one study dropped from 38 kWh/t to 34.2 kWh/t (–10%) with a co‑grinding aid; others note 3–7% typical energy savings on ball mills. Overall plant electricity consumption declines, reducing costs and carbon intensity (SCiELO; NBMCW).
Quality tends to stabilize, too: grinding aids yield more uniform PSD, and analyses show smoother, less‑porous grains that still meet Blaine targets (SCiELO). Higher fineness at the same energy often permits strengths to meet or exceed spec, with slightly better packing properties (for maintenance, steadier quality means more consistent kiln performance downstream).
Wear savings of 5–15% are realistic when fines adhesion is minimized. Even a 1–2 month increase in liner life cuts major fixed costs. Sika’s summary ties “reduced vibration, less wear” directly to proper aid use (Sika).
In Sika’s VRM tests, a new formula delivered +14% mill throughput and −72% vibration versus “no aid” baselines (Sika VRM tests). In ordinary practice, adding 0.02–0.05% aid by clinker mass is sufficient to see multi‑percent efficiency improvements (SCiELO; NBMCW). At current grinding aid prices (often <$10/tonne of cement), the net cost per ton can drop significantly. Adoption is rising: over 50% of global aid consumption is now in Asia‑Pacific (led by China/India), according to industry surveys (Global Growth Insights).
Maintenance playbook and dosing control
Maintenance teams increasingly treat grinding aids as part of the flow sheet. Doses are small (typically 0.01–0.10% by cement mass). Best practice is continuous injection on the hot clinker conveyor just before the mill, or direct spray into the mill inlet, to ensure uniform film on fresh feed. Vendors supply dosing skids and flow meters; automatic metering synchronized to feed rate improves consistency. Many plants specify chemical injection via dosing pumps to control low‑rate addition.
Instrumentation matters. Track mill power, ΔP (pressure drop), and vibration. Introducing or adjusting an aid should slightly lower power draw and ΔP, and a stable vibration decrease is an early sign that coating is suppressed. Check cement Blaine and PSD for the expected fineness shift. If gains stall, verify aid quality, clean dosing lines, or evaluate alternative chemistries (amines vs glycols vs lignosulfonates) matched to clinker.
Inspections remain essential. Compare steel consumption rates (kg steel per tonne of cement) before and after aid use, and review areas prone to fines accumulation (trunnions, diaphragms, discharge screens, silos). The internals should be noticeably cleaner.
Safety and handling: many grinding aids are volatile organics. Sika notes dosing on hot clinker can cause some evaporation (Sika). Provide ventilation at injection points and appropriate PPE (chemical‑resistant gloves, goggles, respirators). Store additive tanks with secondary containment and follow local chemical‑handling rules. Check Indonesian regulations (Ministry of Industry or Environment) for any reporting on VOC or chemical usage; typically aids are used well below regulatory concern levels, but MSDS must be on file.
Supplier engagement helps. Pikmodels: “trial batch” tests in a lab or pilot mill can screen formulations on your clinker. For industrial trials, many vendors support performance guarantees (e.g., “≥5% energy saving or no charge”). Cost‑benefit should include electricity, downtime, and wear‑part life; documented ROI often shows payback within months.
Bottom line and field takeaway
Grinding aids are a proven lever to cut energy and mechanical wear. By dispersing fines and preventing particle‑particle gluing, mills unlock higher throughput at lower power (911Metallurgist; Sika VRM trial). Critically, they decrease coating of the balls and mill lining (SCiELO), reduce mill vibrations (Sika VRM trial; Sika), and extend wear‑part life. Together with energy savings, these effects reduce costs and carbon intensity across the grinding circuit (SCiELO; NBMCW). The maintenance lens is straightforward: longer liner run times, fewer media changes, higher uptime, and a lower unit cost of cement.
Key takeaways
- Properly applied (0.01–0.1%) grinding aids can boost mill output by ~10–15% and cut specific energy by ~5–10% (911Metallurgist; Sika VRM trial).
- They significantly suppress media/liner abrasion by keeping surfaces cleaner (SCiELO; Sika), extending component life and reducing maintenance frequency.
- By tracking before/after metrics (power, ΔP, vibration, wear rate), plants routinely see tangible reductions in cost per tonne. Improved grindability = less stress on parts = longer service life and leaner operation.
Sources and references
Peer‑reviewed studies and industry reports: Zan et al. 2023 (SCiELO; SCiELO); Das 2025 (NBMCW; NBMCW) and technical briefs (Sika, 2024: Sika; Sika; 911 Metallurgist, industry cases: 911Metallurgist; 911Metallurgist) support the data and guidance cited.
