MTW175 Trapezium Mill for Limestone Grinding: Capacity and Selection Key Points

MTW175 Trapezium Mill for Limestone Grinding

When it comes to grinding limestone, the true value of the MTW175 Trapezium Mill lies not merely in its ability to grind the material—since limestone has a Mohs hardness of only 3, almost any roller mill can handle it—but in its stability and cost-efficiency. The geometric fit between the trapezoidal grinding rollers and the grinding ring ensures even wear, while the integrated bevel gear drive maintains consistent fineness regardless of wear; additionally, the built-in variable-frequency classifier allows for switching between 200-mesh and 325-mesh specifications in a matter of minutes. For power plant desulfurization powder (accepted based on D97 standards) and ground calcium carbonate (priced by whiteness and particle size distribution), fineness stability translates directly into price differences per ton. With an estimated daily production schedule of 15–20 hours, a single unit can deliver an output of 150–300 tons per day—making it the ideal "single-machine solution" for achieving full production capacity at medium-sized powder processing plants.

I. Strategic Positioning in Limestone Grinding Capacity: What Problems Does the 175-Class Model Solve and for Whom?

Before discussing equipment selection, one must understand the destination of the powder. Limestone powder is not merely a single commodity but serves three distinct markets, each with its own acceptance criteria:

• Power Plant Flue Gas Desulfurization (FGD): Wet desulfurization absorbents are accepted based on 250–325 mesh specifications, with dual controls on particle size and chemical activity; batches exceeding sieve residue limits face rejection or claims for compensation. This represents the most demanding yet stable source of orders for medium-sized powder plants.

• Ground Calcium Carbonate (GCC) Powder: The 325–400 mesh range is used as filler for plastics, coatings, and rubber. Whiteness and particle size distribution determine the price per ton, with customers conducting batch-based spot checks.

• Construction Materials and Steel Mill Flux: Coarse powder in the 80–200 mesh range sees the highest sales volume and has the most lenient acceptance criteria, serving as the "foundation" for the production line's capacity.

The conclusion is straightforward: an hourly output of 8–15 tons occupies a "sweet spot"—it avoids the wastefulness of running multiple units in parallel while overcoming the insufficiency of smaller, single units. Relying on two small mills to meet output targets doubles the requirements for auxiliary equipment, civil works, electrical controls, and operating personnel; conversely, achieving full production capacity with a single MTW175 Trapezium Mill offers the most direct path to realizing nominal capacity.

MTW175 Trapezium Mill

II. Structural Logic of the MTW175 Trapezium Mill: Three Design Features Determining Limestone Processing Performance

Limestone is relatively easy to grind; therefore, the true competition lies not in whether the material *can* be ground, but in the structural stability and cost-efficiency of the mill during long-term operation:

1. Trapezoidal Grinding Roller Geometry: Uniform Wear and Extended Lifespan

The contact interface between the grinding roller and the grinding ring is trapezoidal, ensuring uniform wear rates across the roller's diameter and edges. This design avoids the common degradation pattern seen in traditional cylindrical roller mills, where a groove forms in the center of the grinding ring, causing the output fineness to gradually coarsen. Coupled with split-type curved shovels—where only the shovel tip needs replacement rather than the entire assembly—wear-part costs are kept within a manageable range.

2. Integrated Bevel Gear Drive: Consistent Fineness

Traditional Raymond mills rely on spring pressure and grease lubrication; as rollers wear, grinding pressure drops and output fineness coarsens over time, necessitating shutdowns for pressure adjustments. This model replaces the suspended pressure structure with an integrated bevel gear drive, ensuring consistent grinding force through the machine's rigid structure and maintaining output fineness within acceptance standards even during the later stages of component wear.

3. Built-in Variable-Frequency Classifier + Centralized Thin-Oil Lubrication: The Foundation for Continuous Production

The classifier features adjustable variable-frequency control, allowing for seamless switching—such as producing 250-mesh desulfurization powder in the morning and 200-mesh construction material powder in the afternoon—without stopping the machine to change parts. A forced-circulation thin-oil lubrication system keeps bearing temperature rise under control, while online monitoring of oil temperature and pressure transforms reactive emergency repairs into planned maintenance. Together, these features guarantee 24-hour continuous production and high batch-acceptance rates.

III. Three Pre-Grinding Prerequisites: Particle Size, Moisture Content, and Hard Impurities

Even excellent equipment requires strict adherence to raw material standards. Unless three key thresholds are met, the production capacity listed in the specifications remains merely a theoretical figure:

• Feed particle size ≤ 35 mm: Ensured by pre-crushing with a jaw crusher or double-roll crusher; oversized chunks can impact the grinding rollers and reduce grinding efficiency.

• Feed moisture content ≤ 5%: Limestone stored outdoors typically contains 3%–8% moisture, with higher levels during the rainy season; excessive moisture causes material to stick to the grinding rollers and clog the classifier and air ducts. High-moisture feed requires pre-drying or blending with dry material.

• Pre-removal of hard impurities: Impurities such as quartz and flint nodules have a Mohs hardness of approximately 7, which significantly accelerates wear on the grinding rollers and grinding rings; installing an iron remover and screening equipment prior to the mill is the most cost-effective investment for extending the mill's service life.

IV. Core Parameters: MTW175 Configuration Specifications for Limestone Processing

The table below outlines the typical parameter ranges for the Baichy MTW175 Trapezium Mill when processing limestone (based on 200-mesh fineness). When selecting a limestone mill, it is recommended to determine the required model and power rating by working backward from the target fineness. Actual production capacity varies depending on the fineness of the finished product, feed moisture content, and impurity levels; the technical agreement for the specific model governs the final contract terms.

Note: This unit (MTW175 model) is an upgraded replacement for traditional Raymond mills, offering lower specific power consumption and reduced maintenance hours for the same fineness. Specific figures are subject to the equipment selection report issued by Baichy following free material grinding tests.

V. Configuring the Complete Line: Five processes to convert single-unit capacity into daily output figures

The main grinding unit represents only half of the production line. Achieving stable, full-capacity output with a "175-series" mill relies on a complete process chain:

Note: Recommended configuration for a medium-capacity limestone powder line (approx. 8–15 t/h at 200-mesh basis). Auxiliary equipment models are sized to the main mill and target output; final line configuration is subject to the signed technical agreement.

Tips for Avoiding Pitfalls in Equipment Selection: When inquiring about price, clarify the specific fineness standard associated with the "8–15 t/h" capacity—the power and model configuration for 325-mesh desulfurization-grade powder differ significantly from those for 200-mesh powder. Also, confirm the power grid specifications (380V/50Hz or 440V/60Hz), altitude, and dust explosion-proof requirements; these factors directly determine the motor and electrical control selection and are often where price inflation is most likely to occur. When signing the contract, request a guarantee of full-capacity output and specifications regarding the replacement cycle for grinding rollers and rings, thereby bringing hidden costs to light within the contract terms.

VI. Selection Boundaries: pision of Roles vs. Raymond Mills, Vertical Mills, and Ball Mills

There is no single "best" mill—only the one best suited to the specific operating conditions:

Vs. Traditional Raymond Mills: For capacities under 5 t/h and high-volume production of coarse construction-grade powder (80–200 mesh), the Raymond mill remains the most cost-effective choice. However, if requirements demand stable acceptance at 325 mesh and long-term continuous production, the structural advantages of the 175-series Trapezium Mill translate into significant differences regarding product pass rates and downtime costs.

Vs. Vertical Mills (Vertical Roller Mills): Vertical mills excel in large-scale operations (exceeding 30 t/h per line) where integrated in-mill drying is required. For medium-scale production of fine-to-medium limestone powder, the Trapezium Mill offers a lower investment threshold and greater flexibility in switching between fineness specifications.

Ball Mill

Vs. Ball Mills: Ball mills offer greater stability for ultra-fine grinding (above 400 mesh); however, within the mainstream 200–325 mesh range, the Trapezium Mill holds a clear advantage in terms of unit power consumption and footprint.

VII. FAQ

Q1: What is the hourly capacity of the MTW175 Trapezium Mill when processing limestone? How fine can the product be?

A1: For limestone applications, the single-unit capacity is approximately 8–15 t/h based on a 200-mesh standard. When targeting 325 mesh, capacity decreases by about 25%–35% compared to 200 mesh (resulting in approx. 5–11 t/h), depending on feed moisture, particle size, and acceptance criteria (D97 or sieve residue). The finished product fineness is continuously adjustable between 80 and 400 mesh, and the built-in variable-frequency classifier allows for rapid switching between grades; it is recommended to verify production capacity targets based on the results of Baichy's free material testing.

Q2: Is it worth upgrading to a Trapezium Mill if I am already using a Raymond mill?

A2: Consider these three questions: Does the customer require acceptance based on specific fineness standards? Is 24-hour continuous production required? Are the costs associated with downtime for roller/ring replacement and pressure adjustment eroding your profits? If even two of these three criteria are met, the upgrade is worthwhile: the integrated bevel gear drive and centralized circulating oil lubrication system eliminate two hidden costs—"fineness drift" and "reactive emergency repairs." While it appears to be an equipment investment in the short term, the long-term result is a dual improvement in cost-per-ton and product pass rates.

Q3: What happens if limestone feed containing moisture and small amounts of quartz is fed directly into the mill? What components are needed for the complete line?

A3: Moisture content exceeding 5% causes the grinding rollers to become coated with material ("mudding") and clogs the classifier and air ducts, necessitating frequent shutdowns for cleaning; hard impurities like quartz and flint significantly accelerate the wear of grinding rollers and rings. The correct approach involves pre-processing: outdoor raw material should first pass through a jaw crusher (reducing size to ≤35 mm) and an iron remover to catch hard debris; during the rainy season, high-moisture material should be processed via a rotary dryer or blended with dry material before entering the mill. Drying and impurity removal are prerequisites for achieving full production capacity, not optional extras. Baichy offers quotes for the entire "crushing–grinding–dust collection–packaging" line, thereby avoiding the compatibility risks associated with piecemeal procurement.

Baichy Heavy Industry

Baichy Heavy Industry is a high-tech mining equipment company integrating R&D, manufacturing, sales, and after-sales service. Focusing on crushing, grinding, and mineral processing equipment, we provide professional solutions to our customers. We are ISO9001:2015 、certified, and our products include mobile crushing palnts, crawler crushing plant, construction waste crushing plants, jaw crushers, sand making machines, cone crushers, fine crushers, grinding mills, ball mills, etc., all with reliable performance to meet diverse project needs.

Baichy Heavy Industry – Your Trusted Partner

To ensure optimal performance of your equipment, Baichy Heavy Industry offers:

• Professional on-site installation guidance
• Comprehensive operator training
• 24/7 technical support & maintenance services

Our complete after-sales service system guarantees long-term, stable operation of your machinery with minimal downtime.

Protect Your Rights – Only Use Official Channels

To avoid scams and ensure authentic support, contact us exclusively through:

• Official Website: www.baichychina.com

• WhatsApp: +8615093222637

• Email: [email protected]

Your satisfaction is our priority – expect prompt, professional service every time.

(Note: Beware of unauthorized third parties claiming to represent Baichy. Always verify through official contacts.)