Preservation
Alternatives to salt*

  • Green processing
  • Drying
  • Dry pickling
  • Chilling
  • Chemicals
  • Australian sheepskins are air-dried
  • Australian woolskins
  • For up to 2 weeks in Australia.
  • During transport in Brazil. For up to 3 weeks in Australia.
Green fleshing Best when fleshings rendered at abattoir

All Wet Processes:

  • Reduced chemical and water use*
  • Efficient washing and drainage
  

Unhairing/Dewooling*

  • Conventional hair saving/fellmongering
  • Partial immunisation ofhair:
    1. Rapidhair-saving inrecyclingDrums
    2. Adaptations for old drums
    3. Enzymes*
  

Deliming

  • CO2 Deliming
  • Elimination of hydrogen sulphide
  • emissions*
  
Surfactants* Alcohol ethoxylates are replacing nonyl-phenol ethoxylates

Pickling

  • No pickle
  • Recycle
  • Salt-free
 Non-swelling acids add to BOD

Chrome utilization

1.       Directliquorrecycle
2.       Precipitation and reuse
3.       High-exhaust systems
4.       Total chrome liquorrecycle

Best if 1 & 2 combined

  1. Requires low float, good control
  2. High capital cost
Fungicide treatment* More effective, environmentally friendly fungicides are needed
Alternative tannages*
1. Glutaraldehyde
2. Minerals eg. Alutan
3. Veg
4. Organic		 All have disadvantages compared to chromium
Precision Splitting* Reduces chrome tanned waste
Retans, dyes and fatliquors*
1. High exhaust
2. Non-toxic dyes and pigments
3. Throughfeed processing
4. Reuse of liquors		 Amphoteric polymers effective
Drying*

Finishing*

  • Aqueous systems
  • Equipment to reduce wastage

    1. Roller coaters
    2. Spray economisers
 Less toxic crosslinking agents needed

Degreasing*

  • Surfactants
  • Enzymes
  • CO2
  • Pickled pelts
  • Woolskins
 Aqueous systems increase BOD/COD

Enzymes*

  • Unhairing/opening up
  • Degreasing
  • Dung removal

Utilisation of waste

  • Fleshings
  • Hair
  • Irrigation
  • Chrome wastes*
  • Leather wastes*
  • Best when green fleshing
  • Used as fertiliser and in compost

Incineration with recovery of energy and chromium may be feasible


* Processes requiring further research

Important quality controls
Recirculating drums
Automation
Good housekeeping
Accurate, comprehensive recording		 No water or compressed air leaks
Minimize spills and washing down
Right first time No wasteful reworking
Mass balances
Process flow sheets
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