1. Project Overview

Diatomite is a biogenic siliceous rock formed by the deposition of ancient unicellular diatom remains. Its main component is opal (SiO₂·H₂O) and its varieties, with SiO₂ content generally exceeding 80%, in addition to metal oxide impurities such as Al₂O₃, Fe₂O₃, CaO, and MgO. China’s diatomite reserves amount to 320 million tonnes, with prospective reserves exceeding 2 billion tonnes, mainly concentrated in East China, Southwest China, and Northeast China, with larger reserves in Jilin, Zhejiang, Yunnan, Shandong, Sichuan and other provinces.

Diatomite possesses unique properties including high porosity, strong absorbency, stable chemical properties, light weight, porous structure, loose texture, and good thermal insulation. After purification and grinding into powder, diatomite can be widely used in filter aids, industrial fillers, catalyst carriers, building insulation materials, and other fields.

This solution aims to provide a complete technical solution centred on Raymond mills for diatomite powder processing projects, covering the entire process from raw material handling, equipment selection, process flow, to environmental protection measures.

2. Raw Material Characteristics and Product Plan

2.1 Raw Material Properties

2.2 Product Plan

Depending on the application field, the fineness requirements for diatomite powder products are as follows:

Recommended product fineness in this solution: 80‑400 mesh (adjustable)

3. Equipment Selection and Parameters

3.1 Equipment Selection Principles

Diatomite has a low hardness (Mohs 1‑2), but requires a relatively high processing fineness (typically 200‑325 mesh or above) while maintaining a good crystal structure. Therefore, equipment selection should consider the following factors:

• Production capacity: determine model based on target output
• Product fineness: different applications have different fineness requirements
• Investment budget: balance between capital investment and operating costs
• Environmental requirements: dust emissions must meet standards
• Automation needs: reduce labour costs

3.2 Recommended Equipment Solutions

Option 1: European‑Style Mill (MTW Series) – Recommended

The European‑style mill (also known as the European Raymond mill) is a technically upgraded version of the traditional Raymond mill and has largely replaced conventional Raymond mills in diatomite and other non‑metallic mineral grinding projects.

MTW158 European‑Style Mill Main Technical Parameters:

Key Advantages of the MTW Series:

1. Significantly increased output: Traditional Raymond mills have a capacity of only 0.5‑9.5 t/h, while the European‑style mill can achieve 3‑55 t/h.
2. Superior environmental performance: The system operates under negative pressure with a pulse dust collector, and dust emission concentration can be controlled below 20 mg/m³.
3. New technologies applied: Bevel gear integral drive, oil‑bath lubrication, and other new technologies. Oil change interval is about 4 months, saving RMB 30,000‑50,000 per year on lubricating oil alone.
4. High degree of automation: Equipped with a PLC fully automatic intelligent control system; monitoring and control from a central control room, requiring only 2‑3 operators per shift.

Option 2: Traditional Raymond Mill (3R/4R/5R Series)

Suitable for small‑scale production, with a grinding fineness of 80‑400 mesh.

Traditional Raymond Mill Features: Processing fineness 10‑325 mesh, capacity 0.8‑9.5 t/h, price approx. RMB 100,000‑500,000, lower energy efficiency and automation, suitable for small processing plants.

Option 3: Vertical Mill (LM Series) – Large‑Scale Production

Vertical mills offer high capacity and large overall investment, but are easy to maintain and have low operating costs, suitable for large enterprises with strong comprehensive strength.

3.3 Equipment Selection Recommendations

4. Process Flow

4.1 Overall Process Flow

The complete process flow for diatomite Raymond mill grinding includes the following main stages:

Raw material → Crushing → Feeding → Grinding → Classifying → Collecting → Finished product

Step 1: Raw Material Collection and Pre‑treatment

Large diatomite raw materials must undergo strict screening and pre‑treatment. For low‑impurity diatomite, a crusher is used to reduce the material to the feed size acceptable to the mill (generally 30‑50 mm). For products with higher quality requirements, additional steps such as roasting to remove organics and acid leaching purification are needed.

Step 2: Feeding

The crushed material is evenly and continuously fed into the Raymond mill feed inlet by an electromagnetic vibrating feeder. Uniform feeding is critical to ensure grinding quality and stable equipment operation.

Step 3: Grinding

After the material enters the main unit, the roller assemblies suspended on the plum flower frame revolve around the vertical axis and rotate on their own axes. Under centrifugal force, the rollers swing outward and press tightly against the grinding ring. The plough blade scoops up the material and throws it between the rollers and the ring, where it is crushed by rolling compression.

Step 4: Classifying

The ground powder is carried by airflow into the classifier (analyzer) for classification. By adjusting the classifier speed according to the mill model and actual production requirements, finished powders of different fineness can be obtained. Oversized particles are returned to the grinding chamber for re‑grinding, while qualified fines proceed with the airflow to the next stage.

Step 5: Collection

Qualified fine powder is carried by airflow into the cyclone separator and pulse dust collector for collection. The entire system operates under negative pressure, effectively controlling dust leakage.

Step 6: Finished Product Packaging

The collected finished powder is discharged through the outlet, subjected to quality inspection, and packaged.

4.2 Process Adjustments for Different Product Requirements

4.3 Process Differences Between Dry and Wet Processing

5. Production Line Configuration

5.1 Standard Production Line Equipment List (Medium‑scale, MTW158 as core)

5.2 Workshop Layout Recommendations

• Arrange equipment in sequence according to the process flow to minimise material transfer distances
• Reserve maintenance space around the main unit
• Locate the dust collection system close to dust generation points
• Place the central control room separately, away from noise sources
• Connect the finished product warehouse to the packaging area

6. Environmental Protection and Intelligent Control

6.1 Environmental Protection Measures

1. Dust control: The system operates under negative pressure with a pulse dust collector; dust emission concentration can be controlled below 20 mg/m³, below the national emission standard. Dust collection efficiency can reach 99%, with zero dust in the workshop.
2. Noise control: The mill body can be enclosed in a soundproof enclosure, and the fan can be fitted with a silencer.
3. Wastewater treatment: If wet processing is adopted, a supporting wastewater treatment system is required.

6.2 Intelligent Control

The European‑style mill is equipped with a PLC fully automatic intelligent control system, capable of:

• Real‑time monitoring of mill speed, temperature, pressure, and other parameters
• Automatic adjustment of operating parameters based on actual conditions
• Remote monitoring and control from the central control room
• Automatic fault warning and diagnosis
• Operation of the entire workshop with only 2‑3 personnel

7. Investment Estimate and Benefit Analysis

7.1 Investment Estimate (for a medium‑scale MTW158 production line as an example)

7.2 Operating Cost Analysis

7.3 Benefit Analysis

• Increased output: European‑style mill output is several times that of traditional Raymond mills
• Reduced energy consumption: Unit power cost saved by over 30%
• Environmental compliance: Dust emissions below national standards
• Intelligent labour saving: Significantly reduces labour costs

8. Project Implementation Recommendations

8.1 Preliminary Preparation

1. Raw material analysis: Test the chemical composition, moisture content, hardness, etc., of the diatomite to be processed
2. Product positioning: Define the target market and required product fineness
3. Site survey: Determine workshop area, power capacity, water supply, and other conditions
4. Equipment selection: Determine model based on capacity and fineness requirements

8.2 Implementation Steps

1. Equipment procurement and customisation
2. Workshop construction and renovation
3. Equipment installation and commissioning
4. Trial production and parameter optimisation
5. Formal production and continuous improvement

8.3 Precautions

1. Diatomite, due to its clay mineral content, has inherent moisture absorption, which affects grinding efficiency; drying treatment should be addressed
2. Feed should be uniform and continuous to avoid fluctuations that affect stable operation
3. Regularly inspect wear parts such as grinding rollers and rings
4. Maintain the dust collection system in proper operation to ensure environmental compliance

9. Solution Summary

This solution, with the MTW series European‑style mill as the core equipment, provides a complete technical solution for diatomite powder processing. The European‑style mill offers advantages of high capacity (3‑55 t/h), adjustable fineness (40‑325 mesh), environmental compliance (emissions <20 mg/m³), and high intelligence (PLC control), making it the preferred equipment for diatomite processing.

For different production scales, traditional Raymond mills (small), European‑style mills (medium), or vertical mills (large) can be selected. Through rational equipment selection, scientifically designed process flows, and strict environmental protection measures, efficient comprehensive utilisation of diatomite resources can be achieved, creating good economic and social benefits for the enterprise.