Roll compactor, dry granulation machine for NPK fertilizer, potash

The roller compactor or dry granulator is used for compaction which is the process of compressing fine-grained solids between two counter-rotating smooth or profiled rollers, it is much similar to the mechanism housed in our roller briquette machine. During the process, the material is turned into a kind of briquette called “flake”, which is an intermediate product. The final granular we would like to get will pass the crushing and screening processes to get the required size range.

Served Industries: Pharmaceutical, fertilizer, food, oil, chemical, etc.

Common material: Potash, NPK fertilizer, kaolin, bentonite, sodium chloride, industrial salt, etc.

Working Principles

simple animation process for compaction

The material passes through the buffer bin, and then goes past the feeder, quantitatively and evenly enters the feed port of the roll briquette machine. After that, it reaches the pre-compression feeding device of the machine.

To maintain a stable material level in the pre-compression feeding device, the screw in the pre-compression feeding device will force the material into the middle of the rolls. The screw will pre-compress the material and remove the gas as much as possible from particles, and moves the material to be transported to the middle of two rolls.

At the arc-shaped notch of the rollers, the pockets of the same shape are evenly distributed on the surface of the two rolls or use even smooth rollers. Through the meshing transmission of the synchronous gear reducer, the two rollers run at the same speed and opposite to each other, thus the material will be transported to the arc-shaped notch. The material is bitten into the groove and forced to compress. As the rolls continue to rotate, when they exceed the center line, the finished flake will fall out of the pocket under the action of its own elasticity and gravity.

Structure and Main Components

structure of the hydraulic roll briquette press

1. Angle reducer 2. Main motor 3. Main gearbox 4. Coupling 5. Hydraulic station 6. Main frame 7. Screw feeding

Transmission

Motor——V belt, reducer or direct——Double shaft output reducer——Coupling——Rolls

Feeding

Screw, double screws, more screws feeding or gravity feeding. Specially designed sealing structure.

Main frame

Surface is cold worked, beams are connected by high-strength bolts.

Lubrication

Central lubrication or point lubrication.

Features

Roll raw material comes from high-quality suppliers, supplemented by Maxton’s excellent processing capabilities and quality control, the life of the roll is very high.
Different roll assembly forms to meet the needs of different customers. Common assembling: tire roll, segment, etc.
Driven by hard-tooth surface output double-shaft reducer, the pressure on the rollers is evenly distributed, the life of the roll is greatly extended.
Reducer comes from top suppliers or Maxton shall produce and manufactures itself to ensure the continuous operation of the equipment under harsh working conditions and provide a strong guarantee for the customer’s operation.
Different feeding forms and feeding structures meet the different requirements of customers. The materials used for the feeding screw are exquisite, and the working life of the screw is improved by using wear-resistant materials and wear-resistant technology.
Sealing structure is improved, no material leakage at low levels after long-term operation, helping customers improve the briquette quality and save running costs.

Applications & Materials

Chemicals (sodium carbonate, sodium chloride, sodium sulphate, sodium nitrate, sodium humate, ammonium chloride, iron sulphate, calcium chloride, calcium nitrate, calcium sulfate, deicing salt, lithium carbonate, aluminum fluoride, foundry additives, foundry salts, bromochlorohydantion, sodium formate, potassium permanganate, sodium dichloro isocyanurate, soda ash, calcium hypochlorite, strontium sulfate, potassium carbonate, carbonate strontium, dicalcium phosphate, sodium metasilicate, sodium silicate, aluminum fluoride, rubber additives, calcium aluminate, TSP, SSP, nicotinic acid, nicotinic acid amine, etc…)
Fertilizers (PK, NPK, potassium chloride, potassium sulphate, ammonium sulphate, potassium nitrate, phosphate, potash slag, micronutrients, urea, wormcast, ammonium sulfate, Russian red potash, Manheim SOP, potassium sulfate, MAP, DAP, ammonium bicarbonate, ulexite, phosphate rock, potassic fertilizer, …)
Detergents
Industrial disinfectant (trichloroisocyanuric acid)
Antioxidant
Animal antibiotics
Polymers, xanthate
Coal or charcoal for production of activated carbon
Oxides (uranium oxide, uranium hexafluoride, chromium oxide, iron oxide, zinc oxide, lead oxide, aluminium oxide, …)
Minerals (burnt lime, dolomite, magnesia, limestone, cryolite, carnallite stone, kaolin, zinc sulfate, …)
Paint pigments
Thermoplastic additives
Nickel ore dust
Clay, bentonite
Dried sewage sludge
Catalysts
Graphite
White carbon black
Bromochlorohydantion
Fillers
Feed additives
Pharmaceutical intermediates
Environmental protection materials
Swelling

System

The Compaction Process

Compaction is a process a bit different from briquetting which will include the next steps of crushing and screening.

Compaction

The powdery material is pre-compressed and degassed by the screw feeder, and is quantitatively and evenly added between the two rollers of the compactor. After being squeezed between the rollers, the pressed material falls off from the pocket under the action of elasticity and gravity, forming a dense, hard strip of flake or briquette. During the compaction process, the pressure on the material gradually increases, when the gap between the two shafts is at the smallest position, the pressure on the material is maximum, and then gradually decreases until it reaches 0. The apparent density of the material can increase by 1.5 to 3 times on compaction.

Crushing

The crushing work will be carried out by the flake breaker under the roller compactor, where the flakes are pre-broken or broken into small granules. Thin granules are easier to transport and are easily further broken by subsequent crushers when needed.

In the crushing process, the softer parts of the flakes are broken into high-strength and wear-resistant particles. These products will not be ground during transportation and use.

Screening

The crushed granules are divided into oversized granules, product granules and fine granules on a multi-stage screen. The fine granules on the lowest screen are recycled into the compactor and then compacted again. The oversized particles retained in the upper layer of the multi-stage screen need to be further crushed. After crushing it returns to screening.

Proper selection of crushing and screening equipment is crucial to the economy of the compacting system. The shape of the granules, the size range of the granules (typically 1 to 5 mm or 2 to 4 mm), and the amount of circulation after crushing and screening determine the output and capacity of the compacting system.

Other related process (optional)

Feeding, handling, mixing, polishing, coating, packing, dust collecting, etc.

potash and NPK fertilizer flake and granules

Benefit of using a compaction process

The materials are compressed into flakes under mechanical pressure, no need wetting agents, ensuring product purity.
The process is brief, energy-efficient, and high-yielding.
Dry powder is directly granulated, eliminating the need for subsequent drying processes, facilitating integration and transformation within existing production processes.
The resulting granules exhibit high strength and significantly improved bulk density compared to other granulation ways.
Flexible in operation, with a wide range of applicability, and the compacting pressure can be adjusted via hydraulic.
Closed-loop system enables continuous production with efficient operation.