How Kady International improves stability for Slurry coal and water and oil.

Coal-water slurries and coal-oil-water slurries are used as pumpable fuels, gasification feedstocks, and pipeline-transportable energy products. Typical formulations combine finely ground coal with water, and frequently a hydrocarbon oil phase, plus dispersants. The commercial performance of these slurries depends on stability: particles must stay suspended, oil droplets must remain finely emulsified, and the mixture must remain pumpable after hours or days of storage.

Kady International has listed this exact duty among its proven applications for decades: “Slurry coal and water and oil with superior stability.” The reason is the design of the Kady Mill itself — a high-speed rotor-stator system that combines pumping, impact, attrition, and hydraulic shear at tip speeds up to 9,000 feet per minute.

Why Coal-Water and Coal-Oil Slurries Lose Stability

Without sufficient energy input at the particle and droplet scale, these slurries fail in predictable ways:

• Coarse coal particles settle rapidly and form hard cakes that are difficult to resuspend.
• Agglomerates remain unwetted, creating weak points that accelerate sedimentation.
• Oil and water separate because droplets are too large and too polydisperse.
• Dispersants never reach every coal surface, so electrostatic and steric repulsion stay incomplete.
• Viscosity becomes inconsistent — too thin at rest (settling) or too thick under shear (pumping problems).

Conventional propeller agitators and low-energy dissolvers circulate the tank but do not deliver the concentrated energy needed to finish particle-size reduction and emulsification.

How the Kady Mill Creates Superior Slurry Stability

The Kady Mill pumps material through radial slots in a high-speed rotor and propels it at tip speeds up to 9,000 ft/min into the staggered slots of a stationary stator. This produces concentrated impact and attrition rather than relying on shear alone. Every particle and droplet is forced through a defined high-energy path.

1. Rapid particle-size reduction

Impact against the stator faces and attrition between particles break agglomerates and reduce coal particle size. Finer particles settle far more slowly (Stokes’ law) and pack more efficiently, allowing higher solids loading without runaway viscosity.

2. Aggressive wetting and de-agglomeration

The high-energy head wets hydrophobic coal surfaces quickly and eliminates “fish-eye” agglomerates. Liberated ultra-fines and mineral matter can contribute a mild structural viscosity that further resists settling while the slurry remains pumpable.

3. Fine, uniform oil emulsification

When oil is part of the formulation, the same high-speed passage through the rotor-stator gap reduces oil droplets to a narrow, fine size distribution. Smaller, more uniform droplets resist coalescence and produce a tighter, longer-lasting emulsion.

4. Complete additive distribution

Dispersants and surfactants only work if they coat every particle. The intense recirculation and high-energy zone of a Kady Mill distribute these additives far more uniformly than bulk agitation, maximizing repulsion between particles.

5. One-step PreMilling

Because energy per pass is so high, many coal slurries reach target particle size and emulsion quality in a single vessel. This can eliminate a separate premix stage and reduce or remove subsequent media-mill passes — shortening cycle time and lowering contamination risk.

Top-Entry and Bottom-Entry Configurations

Kady is the only manufacturer of bottom-entry industrial mills of this type. That matters for slurry work:

• Bottom-entry mills introduce concentrated shear and circulation from beneath the vessel. This improves feed of dense, high-solids slurries and is especially effective for continuous processing and large production tanks.
• Top-entry mills offer flexibility with portable tanks and are widely used for batch development and mid-size production.

Both designs are available from laboratory scale (as small as 1 pint) through production units handling hundreds to thousands of gallons batch, or continuous flow rates from a few gallons per minute to hundreds of gallons per minute. Lab results scale reliably because rotor-stator geometry and tip-speed relationships are preserved across the product line.

Process Advantages for Fuel and Pipeline Slurries

• Longer storage stability — reduced settling and phase separation.
• Higher practical solids loading at usable viscosity.
• More consistent rheology for pumping and atomization.
• Shorter batch times compared with conventional agitators.
• Lower additive usage because surface coverage is more complete.
• Optional jacketed vessels and variable-speed drives for temperature and energy control.
• Wear options (including carbide components) for abrasive coal duty.

From Lab Trial to Production

Kady International offers free testing of customer materials. Sending a coal-water or coal-oil-water sample to the Scarborough, Maine laboratory removes guesswork: particle-size targets, emulsion quality, viscosity, and stability can be confirmed on the same rotor-stator technology that will run in the plant. Because scale-up is predictable, a successful lab or pilot trial translates directly to production models such as the 2C, 4C, 500B, 10T, 100T, or 2000B depending on required volume and throughput.