[Terrapreta] Simple charcoal grinder

[Frank Teuton]

Clear DayHi Len,

Can you, or the list as a whole, refer me to the basics of making charcoal on a small farm scale? I am working on an orchard with regular amounts of prunings, hay/grass clippings and similar materials. For the prunings burning or charring is particularly desirable as it controls pests and diseases completely and is relatively cheap and fast, compared to mechanical shredding either by chipper shredder or brush hog. Our soil is deep sand and would seem a good candidate for terra preta improvement. We can bring in other materials, such as spoiled hay, chipped branch wood, leaves and the like as well. I have heard that chars made in different temperature ranges are good for different purposes, and wonder how practically to manage to get a wide range.

re grinding charcoal, I would think smaller is better....quarter inch seems large to me considering what I have read so far. I would want to take it to 1/8 inch and less and regrind the overs...is there some advantage to the larger chunks I am unaware of? Could a large standing mortar and pestle arrangement also work well for crushing charcoal into fines? This might be particularly portable to very poor areas where small cement mixers are in short supply, and it would be interesting to know the throughput differences of the two.

I have used my cement mixer for mixing potting and seed starting mixes, and second the use of a piece of plastic to reduce dust...bungie cords do a good job of holding it in place. Do you leave the fins in the mixer? and about how full would you suggest for starters? 
Thanks in advance, 

Frank Teuton
  ----- Original Message ----- 
  From: Len Walde 
  To: terrapreta at bioenergylists.org 
  Sent: Tuesday, February 20, 2007 3:11 PM
  Subject: [Terrapreta] Simple charcoal grinder


  I posted this to a small Blog and others might be interested: 
   
   February 20, 2007 
  Simple charcoal grinder: Buy, borrow or rent a small cement mixer, collect a number of round (ish) granite river rocks a dozen or less will do, depends on the size of the mixer, ( and put them in the mixer —  , add the charcoal. Clamp or tie a cloth or plastic cover over the opening, to control dust. Turn it on and go have lunch.

  If your neighbors ask what you are doing, explain, if you like conversation, or don’t — your option. It can be noisy!  I run mine at commute time!

  Good luck.

    Slight update: rock size like a soft ball works well, experiment with the number. Use this idea for compost etc. I screen the output through a 1/4" mesh. Do what you like as to particle size --- experiment.



  Len Walde, P.E.

                 Sigma Energy Engineering, Inc.
  Creative Problem Solving & Process Engineering
  Serving Agriculture, Mining, Industry & Commerce
               through "Symbiotic Recycling" tm
                          Est. 1985

        
        E-mail: sigma at ix.netcom.com




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