Open-circiut Cement grinding plant Introduction

A cement grinding plant is a facility dedicated to the production of cement clinker through the process of grinding the clinker into a fine powder. The cement grinding plant is a part of the cement production line which generally includes the following parts: raw material storage, grinding and milling, material handling, final product storage, dust collecting, etc. The cement clinker produced by the rotary kiln in the cement production plant is coarse-grained and cannot be used directly. It needs to be ground by the vertical roller mill or ball mill in order to be processed to be the final product. The grinding process enhances the reactivity of the clinker and allows it to achieve the desired properties of cement, such as setting and hardening.

Open-circuit Cement grinding plant equipment 

There are various equipment involved in the cement grinding plant, some of them are as follows: vertical roller mill, cement ball mill, cement roller press(HPGR high pressure grinding roller), cement separator, cement dust collector, cement belt conveyor, cement automatic packing machine, cement bucket elevator etc. Tongli offers customized design for your specific need to ensure the smooth operation of the plant.

A Cement Grinding Plant PLC: Programmable Logic Controller system refers to the automation technology used in a cement grinding plant to control and monitor the various processes involved in cement grinding. PLCs are specialized digital computers used in industrial automation and control systems. They are capable of handling multiple input and output devices to execute control functions in real-time.

Vertical roller mill: The cement vertical roller mill has become a popular choice for grinding raw materials in the cement industry due to its significant advantages over traditional ball mill systems, compare to the traditional cement ball mill, it is more energy-efficient and can be exposed outside. The main components of the cement vertical roller mill include the grinding table, grinding rollers, rocker arms, separator, transmission system, base frame.

Cement ball mill: A cement ball mill is a tube grinding machine that used to grind materials into a fine powder. It is extensively used in industries such as cement production, metallurgy, chemical, and others. The material to be ground is fed from the feed end into the rotating drum or shell of the ball mill, along with steel or ceramic balls. The rotation of the drum causes the balls to cascade and grind the material, reducing it to the desired fineness.

Cement ball mill transmission: Central drive ball mill refers to the arrangement of the driving mechanism for the mill. In a central drive configuration, the motor and gearbox are positioned at the center of the mill, usually between the grinding chamber and the mill shell. This design is in contrast to an edge or end drive configuration where the motor and gearbox are situated at one of the ends of the mill. Central drive transmission systems typically involve a motor that powers a gearbox, which then transfers the rotational energy to the mill's main shaft. The central drive design can provide advantages in terms of power distribution and efficiency compared to other drive arrangements. It can also offer better control over the mill's operation.

HPRG transmission: The transmission system for an HPGR typically involves components like gears, gearboxes, and sometimes belts or chains, depending on the design of the machine. These components work together to convert the rotational motion from the motor into the necessary movement of the rollers to generate the required grinding force.

Cement Dust Collector: Usually, the dust collector is used to reduce dust emission as its name indicates, but the dust collector in the cement grinding plant is used to collect and store the finished cement powder sent from the mill powder separator/classifier. After the cement dust enters the dust collector, it will be captured by the filter bag, and finally the finished cement product will be collected and sent to the product silo.

T- Sepax Separator: A 3-way powder separator, also known as a 3rd generation separator or a three-way classifier, is a device used in close circuit cement grinding plants to separate the fine particles from the coarse particles in the finished cement product. It is a crucial component of modern cement grinding systems as it helps optimize the grinding process and improve the overall efficiency of the cement production.

Cement Bucket elevator: Bucket elevator is widely used in the cement production line as well as cement grinding line, its function is for vertical conveying of powder, granular and bulk materials. In our cement grinding line there are two bucket elevator involved, one used for the feeding of the raw material into the vertical roller mill or the ball mill, another one transfers the finished product to the cement silo.

Cement Silo: A cement steel silo, also known as a cement storage silo or cement silo, is a structure designed to store bulk quantities of cement raw material as well as finished product. These silos are commonly used in construction sites, concrete batching plants, and cement grinding plant to store and protect cement from moisture, environmental elements, and contamination. The silo is typically made of steel, which provides durability and strength to withstand the weight of the stored cement and any environmental factors.

Cement truck loading system: A cement truck loading system is a set of processes, equipment, and technologies designed to efficiently load cement and other bulk materials onto cement trucks for transportation to construction sites or other destinations. The primary goal of such a system is to streamline the loading process, minimize material wastage, ensure accurate measurements, and enhance overall safety.

8-spout rotation cement packer: A cement packing machine, also known as a cement bagging machine or cement packaging machine, is a specialized equipment used in cement plants or cement production facilities to efficiently and accurately package cement into bags for storage, transportation, and distribution to customers or construction sites. The machine automates the process of filling and sealing cement bags, ensuring uniform and precise packaging, which is crucial for the safety and handling of cement during transit and use.

Stacker and reclaimer: A reclaimer is a machine used to retrieve or reclaim the stacked materials from the stockpile created by the stacker. The raw materials in the stockpile are usually stored in layers, and a reclaimer is used to extract these materials in a controlled manner. The reclaimer can operate in different modes, such as bridge-type or bucket wheel, depending on the plant's design and requirements. The reclaimed materials are then transported to the next stage of the production process, such as the raw mill, where they are ground and blended before entering the kiln for clinker production.

Process flow of open-circuit cement grinding plant

1. The cement clinker enters the feeding bin through the grab machine.

2. After the cement clinker is measured by the Electronic belt scale, it is sent to the screw feeding device by the conveyor belt to be fed into the Tongli vertical roller mill.

3. The material in the vertical roller mill rotates with the grinding table under the action of centrifugal force, moving from the center to the edge, after the process of compaction, degassing, and grinding, the material is taken up by the hot air from the air ring at the edge of the grinding table, and dried instantly.

4. Fine powder are taken up to the powder classifier for separation. The coarse powder is returned to the grinding table for further grinding.

5. The qualified fine powder is collected by the bag filter, After the finished product is collected, it is conveyed into the finished product silo for storage, and the exhaust gas is discharged by the centrifugal blower.

6. Part of the hard-to-grind large-grained materials (for example iron nodules and iron slag) enter the external circulation system through the slag outlet at the air ring, and are fed into the mill by the bucket elevator again for grinding after iron removal.

7. The hot air required for drying and ventilation of the vertical roller mill is provided by the hot air stove, and the insufficient air volume is supplemented from cold air valve. The system has a large air volume and strong drying capacity, and the maximum moisture content of the grinding material can reach 8-15%.

Design Principles of open-circuit cement grining plant

The open circuit process is simple, easy to use and maintain, and the investment cost of infrastructure is relatively low. It is a relatively economical grinding process. However, when the user has high requirements on the fineness of the product, because of the open circuit process, the material can only be discharged when the fineness of the material meets the requirements. This is leads to the phenomenon of "over-grinding", which is not conducive to the improvement of grinding efficiency and cement output. A typical open-circuit grinding system is a ball mill. Part of the ground material particles have to wait for the coarser material particles to be ground and then discharged together. Most of the fine powder cannot be removed in time, and they continue to be ground in the ball mill, resulting in "over-grinding" phenomenon, which hinders the further grinding of coarse particles, resulting in long grinding time, low output and high power consumption.

Tongli cement grinding plant innovation:

Automation and Control: Implemented advanced automation and control systems to monitor and adjust the grinding process in real-time, maximizing efficiency and minimizing energy consumption.

Compact structure: The entire cement grinding line has a reasonable structure and occupies a small space. The cement grinding production line with an annual output of 300,000 tons only needs 20-25 acres of land, and the annual output of 400,000 tons covers an area of 30-35 acres of land, the annual production capacity of 800,000 tons only needs 40-45 acres of land.

Raw Material Handling: Design efficient systems for handling and storing raw materials such as limestone, clay, and additives. Proper blending and storage facilities are essential to maintain consistent quality.

Grinding Equipment: Appropriate grinding equipment, such as ball mills, vertical roller mills, or roller presses, based on the specific requirements of the plant. Consider factors like energy efficiency, maintenance, and wear resistance.

Material Conveyance: Reliable and efficient material handling system, including conveyors and bucket elevators, to transport raw materials and finished products within the plant.

Quality Control: Incorporate quality control measures, such as online particle size analysis and automatic process control systems, to ensure the production of consistent, high-quality cement.

Low noise: The noise and vibration of the cement grinding line are very low when the production line is running. The fan is equipped with double treatment of sound insulation device and muffler, so that the noise emission of the system is less than 60-70 decibels, which can fully meet the requirements of the industry.

Significant power saving: due to the advanced grinding mechanism, simple process and small installed capacity, compared with the traditionalball mill grinding system, it can save 45-60% of electric power.

Safety: Prioritize safety in the plant's design by implementing safety protocols, emergency response plans, and adequate ventilation systems to protect workers and prevent accidents.

Specifications of cement grinding plant ball mill

Note: * Mill diameter refers to the inner diameter, while the mill length refers to the effective grinding length.

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Industry Knowledge extension

What is the difference between cement production line and cement grinding line?

The difference between a cement production line and a cement grinding line lies in their respective functions and the stages of the cement manufacturing process they cover.

A cement production line, also known as a cement plant or cement manufacturing plant, is a facility that produces cement from raw materials. It involves a series of processes, starting from the extraction of raw materials to the final production of cement clinker. The primary components and stages of a cement production line are as follows:

Raw Material Preparation: This stage involves the extraction and preparation of raw materials, such as limestone, clay, shale, sand, and iron ore. These raw materials are crushed, homogenized, and sometimes pre-blended to ensure a consistent feedstock for the cement rotary kiln.

Clinker Production: In the clinker production stage, the homogenized raw materials are heated in a rotary kiln at high temperatures (around 1450°C) to form clinker. Clinker is a nodular material that is the key intermediate product of the cement manufacturing process.

Clinker Cooling: After leaving the rotary kiln, the hot clinker is rapidly cooled to maintain its quality and prevent it from setting prematurely.

Clinker Grinding: Once the clinker is cooled, it is transported to cement grinding mills, where it is finely ground with gypsum and other additives to produce cement. This grinding process is essential for achieving the desired cement properties.

Cement Storage and Distribution: The finely ground cement is stored in silos before being dispatched for distribution. It can be packed into bags or transported in bulk form to customers or construction sites.

Cement Grinding Line:

A cement grinding line, on the other hand, is a part of the cement production process that specifically focuses on the grinding and final processing of clinker into cement. It is a subset of the overall cement production line and deals with the following stages:

Clinker Grinding: In the cement grinding line, the clinker produced in the cement production line is transported to dedicated grinding mills (such as ball mills, vertical roller mills, or high-pressure grinding rolls) to be finely ground into cement powder. Gypsum and other additives may also be introduced to control setting time and enhance specific cement properties.

Cement Storage and Distribution: Similar to the cement production line, the finely ground cement is stored in silos before being dispatched for distribution to customers or construction sites.

In summary, the main difference between a cement production line and a cement grinding line is that a cement production line covers the entire cement manufacturing process from raw material preparation to clinker production, whereas a cement grinding line is a specialized part of the process focusing solely on the grinding and processing of clinker into cement.

What are the types of ball mill?

Tongli ball mill has following categories: according to the product material can be divided into cement ball mill, mineral ball mill, limestone ball mill, gypsum ball mill, slag ball mill, ore ball mill, raw material ball mill, coal mill; according to the size of the crushed material can be divided into: coarse ball mill, high-fine powder ball mill, ultra-fine powder ball mill; according to the transmission mode, it can be divided into edge transmission ball mill and center transmission ball mill(Gear-less Motor Drive); according to the transmission method, it can be divided into sliding shoe ball mill, bearing bush ball mill and bearing ball mill;

What is the difference between central drive ball mill and edge drive ball mill?

Central Drive Ball Mill and Edge Drive Ball Mill are two common types of grinding mills used in various industrial applications. 

Central Drive Ball Mill: In this configuration, the motor is positioned in the center of the mill, and the shaft is driven directly through the central axis. The motor's power is transmitted to the mill via a gear unit, resulting in a balanced and efficient power distribution.

Edge Drive Ball Mill: In contrast, the edge drive mill utilizes a gearbox located on the periphery of the mill. The motor's power is transmitted to the mill through the gears, which are positioned around the shell. This design offers certain advantages in terms of installation and maintenance.