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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 materials to produce high-quality coal for energy 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 coal processing solutions, we considers ore characteristics, process requirements and environmental constraints to achieve your desired coal quality in terms of calorific value and the level of inherent mud and ash.

Multotec helps you customise and optimise your coal beneficiation process to achieve the required product specification!

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.

Our Coal Processing Solutions:

MATO Conveyor Solutions

Multotec Lacing Systems

MATO Conveyor Solutions from Multotec include belt cutters, clamps,. lacing systems, belt cleaners and accessories.

Sampling Solutions

Multotec wet and dry sampling solutions are used across the world in mineral sampling, mining samples and industrial sampling applications.

Wear Solutions

Our wear solutions provide industry-leading sliding- and impact-resistant linings for high velocity, abrasive material conveyance

Magnetic Separators

Multotec is a leading magnetic separator manufacturer. From the high intensity magnetic separator range to our overbelt magnets, we’ve got the solution you need.

Magnetic Separators that easily separate ferromagnetic and paramagnetic particles – and remove tramp metals – from dry solids or...

Spiral Concentrator

Our gravity separation equipment includes coal spirals and 2 mineral spiral ranges.

Multotec-designed spiral separators are used across the world in coal, gold, iron ore, mineral sands, platinum and chrome processing plants.

Cyclones

The Multotec hydrocyclone range is used in industrial minerals processing applications across the world.

Classification, dense medium and tailings dam cyclones for minerals processing, food processing, waste water treatment and more.

Slurry Pumps

Our slurry pump and centrifugal pump range includes dirty water pump, dewatering pump, sump pump solutions, and more.

Complete range of slurry pumps for medium / heavy-duty cyclone feed, spirals feed, mill discharge, tailings disposal, filter feed and more.

Filter Press

Solid-liquid separation equipment for process water treatment.

Filter press include Seprotech and Micronics brands. The range includes mini filter press and press accessories.

Industrial Centrifuges

The sludge centrifuge or sludge dewatering centrifuge is part of this range.

Industrial Centrifuges from Siebtechnik Tema are tailored for solid liquid separation in the mineral processing industry.

Screening Media

From sieve bends and centrifuge baskets to completely optimised composite screen decks, Multotec is a leading global screening media solutions provider.

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. The first step of the coal preparation process 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. Following sizing, 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.

Using a dense medium cyclone, denser materials are separated from less dense coal at a specific cut density (a specific point of density, which separates the ore into a valuable and non-valuable fraction).

The coal product then flows onto the float drain and rinse screen, used for media recovery and dewatering. This ensures maximum media recovery from the process, resulting in a clean coal product.

Following this, industrial centrifuges are used to achieve effective solid/liquid separation. Multotec’s industrial centrifuges are sourced from SIEBTECHNIK TEMA, an industry-proven, economical and efficient solution for dewatering large quantities of coal to low final moistures.

If required, 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. 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.

Classification cyclones or hydrocyclones are first used to classify, separate or deslime coal particles in a liquid suspension. The overflow, generally less than150 µm, reports to flotation if an economically viable product can be produced. Through the flotation process, the mineral matter is separated from the fine coal (which is smaller than 0.5 mm in size).

The underflow reports to spiral separators/concentrators, which separate the lighter-density coal from the heavier-density material.

The use of dewatering screens is generally the first step in the coal dewatering process. Centrifuges are next, which subject the material to high centrifugal forces through high-speed rotation, forcing further separation of the coal from moisture. On ultra-fine material, moisture reduction is achieved via a filter press to lower the moisture content and produce a filter cake that allows for further solids handling of the material.

Coal Processing Flow Chart:

Increase efficiency and profitability in your coal processing plant with mineral processing machinery and equipment from Multotec.

 

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 via an overbelt magnet, which eliminates any ferromagnetic contaminants such as old bolts, tool shards, and other metallic scrap. Drain and rinse screens are located downstream of the DMS drum in coal beneficiation.

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 can be mined from surface or underground deposits. Coal surface mining is implemented when coal is less than 60 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.

Coal processing plants require machinery that is reliable and durable.

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 “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 magnetic separation.

Coal fines (particles less than 0.5 mm in size) are washed with spiral concentrators. The refined coal and discards are separated with adjustable blades located at different points in the water stream. This allows for separation of products to the required quality.

 

The 4 grades of coal

Lignite

Lignite is the youngest type of coal deposit. This coal is soft and ranges from black to shades of brown in colour.

Because of its colour, lignite coal is sometimes called brown coal.

Lignite is chiefly used for electricity generation and accounts for 17 % of the world’s coal reserves.

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.

This coal makes up 52 % of the world’s coal reserves and accounts for most of the coal industry.

Thermal coal is used in energy generation for heating and metallurgical coal is primarily mixed with iron ore to produce steel.

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?

Coal washing impacts the final coal product and its performance.

  • 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

Why is coal 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 washing the coal, which increases its efficiency and quality, as well as its price. Additionally, coal washing can help to reduce emissions from coal burning.

What is clean coal?

Clean, or pure coal, is produced after coal washing where all other materials are removed. Coal cleaning processes/coal washing can be either physical (mechanical) or chemical cleaning which produces refined coal.

Physical coal cleaning processes: the mechanical removal of coal contaminants using differences in density are the most common processes in use today.

Chemical coal cleaning processes: removal of the organic sulphur by means of an oxidation process. These processes are not used regularly on a large scale.

Improve your coal processing efficiency and lower your cost per ton with Multotec, world-leader in cyclones and spiral concentrators!
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