Multiple Hearth Furnaces

Hankin-Nichols Multiple Hearth Furnace

Hankin is the world leader in custom designed multiple hearth furnaces (MHF) for a variety of process applications. Hankin-Nichols MHF technology has been successfully used for over 90 years. All materials of construction are of superior quality and have been optimized by many years of experience.

The Hankin-Nichols MHF has a long life and requires minimal maintenance. It is extremely flexible, both in range of processing and its ability to accommodate special operations. Gentle rabbling of material aids in mass transfer, and ensures product uniformity and even temperature throughout. Residence time and temperature can be accurately controlled because material is moved mechanically through the furnace.

Hankin engineering and unique expertise has provided MHFs for the following applications:

Carbonization, Carbon Activation, Carbon Regeneration
The Hankin-Nichols MHF helps satisfy the high demand for carbon activation, carbon adsorption processes and charcoal energy throughout the world. In recent years, Hankin has designed and supplied Hankin-Nichols MHFs for producing charcoal, carbon activation, and spent carbon regeneration. Each of these MHF systems was custom designed to produce the desired throughput, product quality, energy, and heat recovery.

Recent commissioned are two (2) 25’-9”O.D. x 17 Hearth and an 54” I.D. x 6 + 0 Hearth carbon activation MHFs in China. Hankin is presently working on two (2) carbon regeneration MHFs scheduled for installation in 2017 and the other in 2018.

Roasting
Hankin recent experience in the design and supply of MHF for roasting mined ores includes a 21’-6” OD x 16 hearth MHF for molybdenum roasting in South America.

Examples of roasting mined ores and products thereof employing MHF include the following:

  • Sulphide ores of Molybdenum, Copper, Lead, Zinc and Nickel
  • Laterite
  • Enargite
  • Pyrite
  • Speiss
  • Arsenical Pyrite Plus Cu, Pb, Zn, Bi, Sb, Co, Au, Ag
  • Cinabar
  • Mattes
  • Litharge
  • Sulphurous Residues

Since 1983 Hankin has designed and supplied over a dozen calciners. Included among the many materials calcined by MHF are:

  • Magnesium Carbonate
  • Magnesium Hydroxide
  • Lime
  • Dolomite
  • Kaolin
  • Uranium (yellow cake)
  • Phosphates, Sulfates, Hydroxides
  • Periclase (MgO)
  • Chromium-Magnesium Sinter (MgO + chromite)

Pyrolysis and Product Recovery
MHFs can be designed and operated under controlled atmosphere (oxygen deficiency) for more efficient incineration of municipal and industrial sludges and wastes, for handling low melting point industrial residues, and for recovery of valuable materials.

Regeneration
In addition to carbon regeneration, a variety of material including bone char, bauxite, fullers earth, diatomaceous earth, foundry sands and certain catalysts can be reactivated, regenerated or reclaimed in a Hankin-Nichols MHF.

Spare Parts
Hankin has available a library of drawings and specifications used when the equipment was originally supplied and we can provide modifications and retrofits to existing MHFs. The following are typical MHF parts we supply:

  • Center Shaft Castings
  • Rabble Arms
  • Rabble Teeth (metal & ceramic)
  • Rabble Arm & Teeth Pins
  • Refractory
  • Top Graphite Bearing
  • Bottom Bearings
  • Fans & Blowers
  • Burners & Parts
  • Door Frames & Doors
  • Intermediate Lute Caps
  • Upper & Lower Center Shaft Seals
  • Center Shaft Drive, Master, and Pinion Gear