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Iron Smelt - Wareham, ON - Nov 5, 2011

Date:Nov 5, 2011

Location:Wareham, ON

See also: Darrell Markewitz's ironsmelting site

Team: Neil Peterson, Darrell Markewitz, Ian Fleming, Lloyd Johnson

Premise: Second pass at Slag Pit but with better ore

Furnace Design

TypeNorse short shaft cobb construction, tap arch
Extractiontop
Diameter25 cm
Height55 cm
Volume26984.375 cm3
Tuyure Typeceramic tube
Tuyere height from base12 cm
Tuyere penetration into furnace5 cm
Tuyere angle22 deg
Base designslag pit - 39cm deep, tapering from 28.5 to 26cm in diameter cm

Burn Details

Bellow Typeblower
Avg Air rate900 litres per minute
Total Charcoal Mass49 Kg
Avg Burn rate12 min per 2 Kg
Ore Typetaconite
Total Mass of Ore19.2 Kg
Burn Duration5:30 Hours

Results

Mass of Bloom6.405 Kg
Bloom Type
Yield33%
Notes

Smelt_cd Reports of all of our iron smelting efforts along with more articles and information are available on the "Iron Smelting in the Viking Age" CD from the Wareham Forge.  Copies of the CD can be purchased here.

Discussion:




Conclusions:


This experiment builds on the system profile from October 8. As was suspected, the general layout of the pit and furnace combination proved workable. The shift to a iron rich ore completed the mechanism, the proof being in a high yield of nicely dense, forgeable iron bloom.

The operation of the furnace was virtually flawless. At no time was any significant liquid slag observed at the tuyere, with no interuption of air. Intentionally the consumption rate was kept to the 10 - 12 minute per standard (1.8 kg) charcoal measure. This was because of a concern the pure taconite ore might tend to produce a high carbon cast iron otherwise.

One other result was that the furnace itself has proven both stable and durable. After the smelt, the body of the furnace was carefully placed on wooden planks, then slid off to one side of the smelt area. After the slag block was excavated, the retaining walls were replaced, the pit filled with earth / ash / slag mixture. With the furnace body slid back into place, there is no reason that another smelt could not be undertaken using the same structure. Noteably, the ceramic tuyere, which at this point has endured three separate full smelts, shows every sign of being able to withstand yet another.

Photos:


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Smelter SetupBig BloomSlag block

Raw Data:



CLOCK ELAPSED EVENT AIR     CHARCOAL     ORE    
            UNIT COUNT TOTAL UNIT COUNT TOTAL
      gage LpM P bucket   kg scoop kg kg
                      0.28
12:00   start bark pieces pre-heat 3 300              
12:50 :50 fill with rough charcoal 8 800   3 3        
13:15 :25 reaction column hot                  
13:20 (1:20) pre-heat complete       3 6 10.80      
                       
12:00   main sequence start                  
12:10 :10 graded charcoal       1 7        
12:23 :13         1 8        
12:34 :11         1 9        
12:45 :11 finish 8.5 kg / increase air 9 900   1 10 8.50      
12:51   first ore addition             at 3/4    
13:00 :15         1 11     1 1
13:11 :11         1 12     1 2
13:22 0:11         1 13     1 3
13:34 0:12         1 14     1 4
13:45 0:11 finish 8.75 kg       1 15 17.25   1 5
13:58 0:13         1 16     1 6
    increase ore amount             at 1.25    
14:10 :12         1 17     1.5 7.5
14:22 0:12 finish 6.75       1 18 24.00   1.5 9
14:34 0:12         1 19     1.5 10.5
14:42 0:08         1 20     1.5 12
    increase ore amount             at 2    
14:51 :09         1 21     2 14
14:58 0:07         1 22     2 16
15:07 0:09 finish 9 kg       1 23 33.00   2 18
15:13 0:06 all ore added       1 24     1.2 19.2
15:17   reduce air 8 800              
15:24 :011         1 25        
15:31 0:07 final charcoal added / burn down       1 26 38.40      
15:41   reduce air 5 500              
                       
16:00   approximate extraction time                  
                       
    TOTALS                  
                       
  TIME pre-heat 1:20 hrs              
    main sequence 4 hrs              
    TOTAL 5:30 + hrs              
                       
  ORE TOTAL - taconite 19.2 kg              
                       
  CHARCOAL rough 10.8 kg              
    graded 38.4 kg              
    TOTAL 48.4 kg              
                       
  BLOOM TOTAL 6.4 kg              
    YIELD 33 %              
Smelt_cd Reports of all of our iron smelting efforts along with more articles and information are available on the "Iron Smelting in the Viking Age" CD from the Wareham Forge.  Copies of the CD can be purchased here.
Text © Darrell Markewitz   Photographs © Darrell Markewitz   Copyright details
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