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Blending Silo Techniques - Bulk Material Handling

Product Announcement from FLSmidth

Blending Silo Techniques - Bulk Material Handling-Image

Four powerful solutions to save you time & money - Air and gravity-based equipment for a mixture of energy-efficient, cost effective, low maintenance and space saving blending. At FLSmidth we engineer all our blending silos to maximize the benefits of fluidization and gravity technologies over mechanical…

Technologies that give you operating efficiency, flexibility and increased productivity. Our product range can also combine storage and blending for space saving plant layouts.

Blending Applications

  • Mixing two or more products
  • Homogenation of individual products
  • Size uniformity
  • Color uniformity
  • Chemical uniformity
  • Temperature uniformity
  • Reduce process variations
  • Recycle out spec material
  • Add trace elements
  • Chemical modification

Fuller® Random-Flow

Six pie-shaped sectors (each subdivided into six aeration zones) and continuous blending in a timed discharge pattern provide the lowest energy gravity blending silo available. Power consumption on cement raw meal as low as 0.07 kWh / metric ton! New and retrofit installations with minimum downtime.

When an aeration zone is activated, layers are mixed through a funnel effect as material in the zone flows to its designated collection point on the gathering Airslide™ conveyor. The inverted cone prevents material exiting without flowing through a collection point


  • No moving parts
  • Low pressure air
  • Compact PD blowers
  • Gravity withdrawal
  • Center or side discharge
  • Maximum bottom aeration coverage
  • Small inverted central cone


  • Reduced maintenance
  • Clean, dry, oil free
  • Low power usage
  • Space on ground floor
  • No segregation
  • Flexible plant layout
  • Maximum cleanout
  • Low installation cost
  • Maximum storage capacity

Central Inverted Cone

Central Inverted Cone-Air Assisted Gravity Blending. Multiple outlet gravity discharge combined with central cone construction gives advanced gravity blending and storage with a power consumption as low as 0.25 to 0.5 kWh / metric ton of cement raw meal.

Open Airslide™ sections in the flat annulus ensure full clean-out when required.

Material enters the central bin via multiple Airslide blending materials from different areas of the silo floor.

An arrangement of air valves activates sequential discharge and provide a continuous blending of materials from the side of the silo through a funnel effect.

Features include:

  • Total cleanout
  • High capacity (6,000 ton +)
  • High discharge rates (150 tph+)
  • Controlled flow withdrawal
  • Reduced silo profile
  • Discharge equipment located under cone
  • Minimum dust collection
  • No segregation
  • Reduced foundation cost


A porous membrane over the whole bin bottom, 4 air plenums and a simple flow control system enable air blending by changing the density of material in the fluidized bed of material to generate a gentle folding action and a near perfect blend.

Airmerge Blenders can be designed for batch or continuous operation to meet your requirements.

Porous fabric held with binding strips on top of removable grating panels in the Air Plenum allowing access for fabric to be replaced in place.

Higher air velocities in the blending quadrant lower the bulk density causing the denser material in the three fluidized quadrants to flow into it and be displaced upward in a continuously circulating bed.

Air for fluidization and blending can be supplied from common or separate blowers as required.


  • No moving parts in contact with the material
  • Simple operation
  • Gentle blending action
  • Low pressure air
  • ~20° slope on fluid bed
  • Steel flange connection
  • Batch or continuous working
  • Standard and FDA fabric option


  • Low maintenance
  • Long life
  • No complicated controls
  • Little dynamic loading
  • Usually PD blowers
  • Complete cleanout
  • New or retrofit installations
  • System design flexibility
  • Food applications available

Column Blender

A fully fluidized cone, an upper and lower air plenum and an open-ended central column allow the principle of air blending to be applied to even the most difficult materials.

The fluidizing air enters the cone beneath the column, reducing the density of the material within which is displaced upward as the denser material from the annulus of the cone flows inward.

This "Fountain-Flow" gives a radial circulation capable of blending ultra-fine powders, coarser sandy materials and products with a wide particle size distribution.


  • No moving parts
  • Gravity discharge 60° cone design
  • Simple operation
  • Robust design
  • Greater flexibility in particle size range
  • Design for different batch sizes available*

* Different Batch Sizes

By dividing the central column into two or more separate pieces, the column blender can accommodate different volumetric batch sizes.

In the smaller batches, material is lifted up in the same way but "Fountain-Flow" into the surrounding fluidized bed is via the spaces between the upper and lower column.

Batch volumes must be known for design purposes in advance.