The large generation of coal combustion products in India has given birth to plenty of unorganized traders and exporters, who have no product knowledge nor any understanding of the business. Such fly-by-night operators often rely on malpractices to misguide customers and sell substandard quality products at cheap, below-market prices to make a quick buck. Recently, some rogue traders have started supplying highly coarse Fly Ash with a layer of fine Fly Ash on top of the big bag to cheat customers.

Beware, a lower price always comes with compromises and risks. An apparent short-term gain could get wiped out by much bigger losses and long-term damage to the reputation and business of the buyer - with disastrous effects on concrete and significant construction hazards perhaps leading to death of people in case the concrete structure collapses!

Please check the following before procuring coal combustion products/ Fly Ash from any supplier:

Authenticity

• Valid long-term supply contract with the multiple thermal power plants (to ensure supply security with back-up)
• Verifiable sales volumes in past 12 months and customer testimonials
• Financial standing and resources of the company (due diligence reports can be bought online)

Investments

• Investment in the business – is he a trader or has he invested in processing/ classifying infrastructure, quality control, bagging plant and warehousing/ logistics

Organization

• Team size and structure
• Bios of management, technical and operations personnel
• Sustainability focus and business continuity planning

Quality Control

• Quality control process document and understanding of coal source - domestic or imported? Imported coal source results in quality and colour variability
• Historical quality data, third party test reports and colour of ash (photos). Guaranteed fineness and consistency
• Detailed bag specifications to see GSM of fabric, weight of bag, liner, lamination, etc.

Operations

• Supply chain capabilities
• Assured load rate in case of bulk exports, along with loading equipment, process, photos and risk management process

Coal source has a direct impact on the quality of coal combustion products, therefore it is very important to check if the thermal power plant has a stable coal source. Most coastal thermal power plants use imported coal from multiple sources based on economics. This significantly impacts quality of Fly Ash - the chemical properties as well as colour are very inconsistent and non-uniform - they change without notice! For the end-user, this creates serious problems because the concrete mix-design, performance and colour will be different every time which is not acceptable in projects.

Therefore, it is advisable to get Fly Ash from a thermal power plant with stable coal source to ensure consistent quality and colour. Thermal power plants with single source, domestic coal source are highly recommended as they provide consistent quality Fly Ash with uniform colour.

Fly Ash is a by-product of coal combustion in thermal power plants. The colour of Fly Ash is dependent on the coal, which is mined from Earth. The colour of Fly Ash can vary from tan and light colour to brownish, grey and dark grey colour, depending on the coal source. It can even vary in shades for the same coal source, depending on the layer of coal mined. While one must ensure that physical and chemical properties of Fly Ash fully comply with the required international standards, the colour of Fly Ash has no impact on the its performance in concrete and other applications. The performance of Fly Ash depends on various parameters like fineness, LOI, chemical properties, etc. and is independent of colour per se.

However, frequently changing, inconsistent and non-uniform colour of Fly Ash can create issues in projects as it directly impacts the colour of concrete. Hence, a stable coal source is essential in the thermal power plant from where Fly Ash is being supplied, and single source, domestic coal source is preferred.

The discharge of big bags into bulk tankers or batching plants is very often problematic, due to lumps created by fine particles due to vibration, ambient humidity, temperature fluctuations and compaction during shipping, transportation and storage.

JAYCEE recommends a simple but effective de-bagging facility to remove lumps, and load bulk tankers/ silos in a dust-free manner. The debagging equipment is furnished with an in-built lump breaker macerating any material containing lumps again into free flowing powder. Two operators are required to man the system and one forklift or Hydra is required to carry the big bags to the lift-up point of the de-bagging station. All large customers and distributors in every territory should install a de-bagging station with in-built lump breaker to have seamless discharge of big bags. JAYCEE can also provide such systems in cases where it is not available locally.

The particle size of Fly Ash (fineness) measured as retained over 45 micron sieve, is a very important quality parameter which determines the performance of concrete. Modern thermal power plants have advance technologies for effective pulverization and efficient combustion of coal, with integrated electro-static precipitators with multiple fields for segregating and capturing Fly Ash of different particle sizes.

The fineness can be controlled and made as per required specification either by selective extraction from ESPs of thermal power plants, or by processing/ classification of the Fly Ash. Processing/ classification is definitely a more robust and superior way to produce highly consistent quality Fly Ash of different fineness grades for different applications. To go to ultra-fine particle size, a multi-stage processing/ classification system is used.