Lignite
Lignite is the youngest type of coal deposit. This coal is soft and ranges from black to shades of brown in colour.
Lignite is chiefly used for electricity generation and accounts for 17 % of the world’s coal reserves.
Coal Processing
Coal processing or coal beneficiation uses physical (mechanical) and/or chemical methods to remove rocks, dirt, ash, sulphur and other contaminants and unwanted substances to produce high-quality coal for energy and metallurgical applications in both local and export markets.
Multotec manufactures a complete range of equipment for coal processing plants, from the Run of Mine (R.O.M) stockpile to the tailings dam, including:
- Screening equipment
- Sampling equipment
- Gravity separation equipment
- Beneficiation equipment
- Dewatering equipment
When developing processing solutions for the coal mining industry, we consider ore characteristics, process requirements and environmental constraints to achieve the desired coal quality in terms of calorific value or ash content.
Multotec helps to customise and optimise your coal beneficiation process to identify the most economical processing route to achieve the required product specifications!
Get in touch with Multotec today to see how we can improve efficiency and lower the overall costs of your coal processing plant and get more from your ore.
View how Multotec coal processing equipment is designed for all stages of coal processing in this industry flowsheet.
Our Coal Processing Solutions:
MATO Conveyor Solutions
MATO Conveyor Solutions from Multotec include belt cutters, clamps, lacing systems, belt cleaners and accessories.
Sampling Solutions
Multotec supplies a range of mineral processing sampling solutions that provide precise, unbiased samplers for all minerals and commodities.
Wear Solutions
Our wear solutions provide industry-leading sliding- and impact-resistant linings for high velocity, abrasive material conveyance
Magnetic Separators
Magnetic Separators that easily separate ferromagnetic and paramagnetic particles – and remove tramp metals – from dry solids or...
Spiral Concentrator
Multotec-designed spiral separators are used across the world in coal, gold, iron ore, mineral sands, platinum and chrome processing plants.
Cyclones
Classification, dense medium and tailings dam cyclones for minerals processing, food processing, waste water treatment and more.
Slurry Pumps
Complete range of slurry pumps for medium / heavy-duty cyclone feed, spirals feed, mill discharge, tailings disposal, filter feed and more.
Industrial Centrifuges
Industrial Centrifuges from Siebtechnik Tema are tailored for solid liquid separation in the mineral processing industry.
Screening Media
We supply polyurethane, rubber and wedge wire modular screen panels, trommels, sieve bends, statics, baskets and more!
Get in touch with your local mineral processing specialists.
Multotec’s equipment supports your entire coal beneficiation process. Send us your requirements!
Coal Processing Steps:
Remove impurities from the coal for a more efficient and cleaner burning fuel with coal processing equipment from Multotec.
Step 1: Size reduction and sizing
Involves feeding the ore through a size reduction machine which is typically a roll crusher or mineral sizer. Thereafter the material is placed on a sizing screen. Any tramp metal that is present at this stage is removed via an over-belt magnet.
Step 2: Dense medium separation
Coarser coal is fed to a dense medium separator (DMS) drum or a large diameter dense medium cyclone.
If a dense media drum is used, the intermediate size fraction reports first to a desliming screen, followed by the dense medium cyclone, which is more suitable to process the smaller size fractions effectively.
Step 3: Media recovery and dewatering
The coal product (floats) flows onto the drain and rinse screen, used for media recovery and dewatering. This ensures maximum media recovery from the process, resulting in a clean coal product. The coal waste (sinks) also discharges onto a drain and rinse screen for media recovery purposes.
Step 4: Additional screening
The product can be screened further into different-sized fractions.
The material reporting to the desliming screen is screened to remove any ultra-fine coal particles.
Step 5: Ultra-fine coal separation
Ultra-fine coal particles are fed through a classification cyclone followed by spiral separators or other water-based separation equipment, flotation, screens and centrifuges or filter presses.
Step 6: Dewatering process
The use of dewatering screens is generally the first step in the coal dewatering process. Centrifuges then subject the material to high centrifugal forces through high-speed rotation, forcing further separation of the coal from moisture.
Coal Processing Flow Chart:
View how Multotec coal processing equipment is designed for all stages of coal processing in this industry flowsheet.
Coal Beneficiation Benefits From Multotec
Coal beneficiation machinery from Multotec enables you to achieve your processing goals at the lowest cost per ton. We supply coal beneficiation equipment for the entire process, from R.O.M stockpile to dewatering.
Our coal processing solutions:
- Remove contaminants and lower-grade coal from the coal stream
- Achieve the sharpest particle separations over extended periods of trouble-free operation
- Solutions for fine and coarse coal
Designing a Flow Sheet for Your Coal Beneficiation Application:
Multotec can customise your coal beneficiation process according to the calorific value, level of inherent mud and ash, as well as the desired coal quality.
The first segment of the coal beneficiation process involves feeding the ore through a roll crusher and then sizing screen.
Following sizing, the coarser coal is fed to a DMS drum or large diameter DMS cyclone via a conveyor fitted with an overbelt magnet, which eliminates any ferromagnetic contaminants such as old bolts, tool shards, and other metallic scrap. In coal beneficiation, drain and rinse screens are located downstream of the DMS drum or large diameter DMS cyclone.
Finer coal particles are fed from the sizing screen to a desliming screen to remove ultra-fine coal particles. Ultra-fines are fed through a classification cyclone, flotation, spiral separators, screens and centrifuges or filter presses. Less fine particles are fed through a DMS cyclone, screens and centrifuges.
The Extraction and Processing of Coal
Coal mining can involve extracting coal from surface or underground deposits. Coal surface mining is conducted when coal is less than 90 metres underground. Large machines remove the topsoil and layers of rock known as overburden to expose coal seams. Mountaintop removal is a form of surface mining where the tops of mountains are dynamited and removed to access coal seams.
Underground mining, or deep mining, is necessary when the coal is roughly over 90 metres below the earth’s surface. Some underground coal mines are hundreds of metres deep with tunnels that may extend out from the vertical mine shafts for kilometres.
Our team of metallurgists and engineers will help devise the optimum solutions for your plant. Contact us!
Modern Coal Cleaning Technology
Modern coal cleaning technologies include DMS cyclones and spiral concentrators.
With DMS, very accurate density separation can be achieved within a short time frame.
Currently, the most efficient coal beneficiation method is the “float-and-sink separation” which increases productivity and separation. By using cyclones with accurate cut-point control, different densities of coal can be separated. DMS makes use of magnetite as a separation medium to improve the accuracy of cut-point separation. The magnetite is later recovered from the coal through drain, rinse screens, and magnetic separation.
Coal fines (particles less than 0.5 mm in size) are beneficiated with spiral concentrators. The refined coal and discards are separated with adjustable blades located at different points in the slurry stream. This allows for separation of products to the required quality.
The 4 grades of coal
Subbituminous
Subbituminous coal is the result of millions of years of continued pressure and high temperatures on lignite.
Due to its low sulphur content, it burns cleaner than other types of coal, producing less greenhouse gas emissions.
It is used in electricity generation and industrial processes, making up 30% of the world’s coal reserves.
Bituminous
Bituminous coal is harder and blacker than lignite and subbituminous mineralisation and can be divided into two types: thermal and metallurgical.
Used in energy generation for heating and mixed with iron ore to produce steel, this coal makes up 52 % of the world’s coal reserves and accounts for most of the coal industry.
Anthracite
Anthracite is the most mature form of coal deposit and holds the highest carbon content of any coal type.
Also known as hard coal, mines that produce anthracite or hard coal account for roughly 1 % of the world’s total coal reserves.
This is a very small part of the overall coal industry, but is of the highest quality, with the highest calorific value.
Innovation driven by R&D:
We are specialists in coal beneficiation and supply our equipment globally. The effects of Multotec’s equipment in coal beneficiation achieves optimum results in processing. This is the result of 50 years of finding solutions to process more ore at a lower cost.
Our R&D programme responds to real-field challenges as well as cutting-edge coal beneficiation technologies so that we can constantly look for places where process efficiency can be increased.
Multotec’s R&D aims to enhance mineral and coal beneficiation through increasing product speed to market; high levels of product consistency and reliability; for OEMs to assume the role of solution providers; and the recycling of customers’ products at the end of their working life.
Did You Know?
- China accounted for approximately 51.7% of the world’s total coal consumption in 2019, and India at 11.8%.
- The largest coal reserves in the world are in the USA, Russia, China, Australia and India.
- Currently, the proven coal reserves worldwide sit at an estimated 1.1 trillion tonnes.
Frequently Asked Questions
What is the distribution of the world's coal reserves?
The United States holds the largest share or coal reserves, with about 22% of the world’s proven coal reserves, followed by Russia (14%), Australia (13%), China (13%), and India (9.5%). Together, these nations dominate both global coal consumption and the distribution of coal reserves, with proven coal reserves worldwide estimated at approximately 1.1 trillion tonnes.
Why is coal beneficiated (“washed”)?
Before coal can be sold to consumers, other materials that are within the ROM, such as pieces of rock, sulphur, sand, and various materials, must be removed. This is done by beneficiating or washing the coal, which increases its efficiency and quality and reduces emissions from coal burning. The principle of the separation process is based on the fact that the coal and impurities have different solid densities and the benficiation process separates the light material (coal) the from the heavy material (waste).
What is clean coal?
Clean, or pure coal, is produced after coal beneficiation or washing when all other materials are removed. Coal cleaning processes/coal washing can be either physical (mechanical) or chemical cleaning which produces refined coal.
What is the coal beneficiation (“washing”) process?
There are several steps involved iinvoloved in coal processing. First, coal is extracted from mines, either through surface mining or underground mining methods. It then enters the coal preparation plant process where it is washed and impurities such as soil, rocks, and ash are removed. The cleaned coal is then dried, and in some cases, further treated to improve its energy content and suitability for specific uses. Finally, the processed coal is stored and transported to its destination for combustion in power plants, steel production, or in other industrial uses.
What are the 4 stages of coal?
The four stages of coal formation are peat, lignite, subbituminous and bituminous, and anthracite.
How do you process raw coal?
Coal processing plants have several steps to improve raw coal quality and prepare it for industrial use. The coal processing methods include crushing, where raw coal is crushed into smaller pieces to facilitate handling and further processing. The screeninig process then takes place to separate it into different sizes based on its intended use. The next step is coal beneficiation or washing, where water or other methods are used to remove impurities such as clay, ash, and sulfur. Once cleaned, the coal is dried to remove excess moisture, which can reduce its heating value. Finally, the processed coal is sorted, stored, and transported for use in power plants, steel production, or other applications where high-quality fuel is required.
Need a quote on coal processing equipment?Send us your requirements
In the news:
- Multotec shares new technologies and product development with Anglo Coal
- Multotec adding greater value to the coal processing sector
- Multotec shares fine coal beneficiation expertise with Indian coal sector
- Two overbelt magnets delivered to Mpumalanga coal mine
- Multotec supports drive for quality coal sampling
Improve your coal processing efficiency and lower your cost per ton with Multotec, world-leader in cyclones and spiral concentrators!