Ball Mills & Grinding Machines – Xinhai Mineral Processing EPC

Raymond Roller Mill for Limestone & Non-Metallic Minerals

Wed, 17 Jun 2026 16:57:53 +0000

The Raymond roller mill, also called a Raymond pulverizer, is a closed-circuit dry grinding system for non-metallic minerals below about Mohs 7. Unlike a wet ball mill, it produces a dry powder and integrates grinding, classification, and collection in one footprint, which makes it the default choice for limestone, calcite, gypsum, dolomite, barite, and kaolin powder plants.

How it works

Material drops onto a rotating grinding table where spring-loaded rollers press it against a stationary ring. An upward air stream lifts the ground powder into an integral classifier; particles at target fineness pass through to the cyclone and bag collector, while oversize falls back for regrinding. The result is a tightly controlled product distribution with low residue.

Adjustable fineness: typically 80-325 mesh, up to roughly 400 mesh on softer minerals.
Dry, closed-circuit operation: no slurry, no dewatering step.
Integrated classifier and dust collection for a clean, compact line.

Selection and sizing

Three variables drive mill selection: feed hardness and moisture, target fineness, and required output. Softer minerals at coarser settings give the highest throughput; pushing fineness toward 325-400 mesh lowers capacity, so the classifier speed and roller pressure are tuned accordingly. Feed moisture should generally stay under about 6% for stable airflow. As a manufacturer, Xinhai offers a range of roller numbers and ring diameters rather than one model, so capacity and motor power are matched to your powder spec.

For minerals that are too hard or that need a wet flowsheet, a tumbling mill is the better tool; see our wet ball mill and the wider ball mills and grinding machines category. To understand where grinding sits relative to classification, our guide on choosing a grinding mill covers the circuit logic.

Wear parts and operating cost

The main consumables are the roller sleeves and grinding ring, both made from wear-resistant alloy and stocked as spares. Because the mill runs dry with internal classification, operating cost is driven mainly by power and wear-part replacement rather than reagents or water. Energy-efficient design and a well-tuned classifier keep specific energy competitive for fine powder duties.

Tell us your mineral, feed size, target mesh, and tonnage, and we will recommend a configuration with budget and lead time. Start the conversation on our contact page.

Wet Ball Mill for Ore Grinding | Grid & Overflow Types

Wed, 17 Jun 2026 16:57:54 +0000

The wet ball mill is the workhorse of the grinding circuit, sitting between crushing and concentration. It takes crushed ore (typically -25 mm), grinds it in a water slurry, and delivers a controlled particle size to flotation, gravity, magnetic separation, or leaching. Because grind size drives liberation and downstream recovery, mill selection is one of the highest-leverage decisions in a flowsheet.

Grid type vs. overflow type

Two discharge designs cover most duties. The grid (grate) type uses a discharge grate that pulls product out quickly, giving a coarser grind, higher throughput, and lower over-grinding risk. It is the common choice for the primary stage and works well ahead of gravity or coarse flotation circuits. The overflow type holds slurry longer, producing a finer, more uniform product, which suits secondary grinding and fine-flotation or leach feed.

Grid type: coarser product, higher capacity, ideal for primary grinding and closed circuit with a spiral classifier.
Overflow type: finer product, simpler design, common in regrind and leach-feed duties.

How Xinhai sizes a wet ball mill

We start from your ore: Bond work index, feed top size, target P80, and required throughput. From there we set drum diameter and length, ball charge, liner profile, and motor rating. Energy-efficient rubber or composite liners cut wear-part cost and noise, while a properly matched ball charge keeps specific energy down. Most metallic-ore circuits target 70-85% passing 200 mesh (about 75 microns), but we tune to your liberation curve.

As a manufacturer offering OEM and ODM, Xinhai builds units across a wide capacity band rather than a single fixed model. Common wear and spare parts, gear and pinion sets, and trunnion bearings are stocked to keep lead times and maintenance predictable.

Where it fits in your plant

A wet ball mill rarely works alone. It runs in closed circuit with classification, feeds flotation or magnetic stages, and can be integrated into a complete turnkey concentrator. If you are weighing single-stage versus two-stage grinding, or grid versus overflow, our guide on how to choose a ball mill walks through the trade-offs, and the full ball mills and grinding machines range covers related units.

Send your ore type, feed size, target grind, and desired tonnage and we will recommend a configuration and budget. Reach the engineering team via our contact page.