Lime Squad III: Burning lime in metal drums. Advantages, limitations and where to go from here.

THIS BLOG IS RETIRED, I’VE MOVED TO SKILLCULT.COM   

ALL THE OLD TURKEYSONG POSTS ARE THERE AND MORE, CHECK IT OUT!

This update is loooong overdue.  In fact, it was started maybe as much as a couple of years ago, but never finished.  So overdue in fact, that I’ve divided it into two parts.  This part will deal with burning in a metal drum, while part two next week will assess some clay and straw kilns that were built later on.

Warning, extreme geekage ahead!  This will be TMI for most people, but hopefully useful for those who want to understand and pursue lime burning.  Although I think using a drum is not the greatest, I’m using it as a reference point to try to understand and relate the process as a stepping off point, because this has been our evolution.  Future posts may be more along the lines of “how to do this right”.  This article is somewhat of a chronicle of an evolution, but contains a lot of relevant ideas and information to help the would be lime burner better understand the issues involved.

Lime burning at Turkeysong is pursuing broad goals.  One goal is to make home-scale lime burning practical enough to use in development of infrastructure here on the land.  I’m also interested in assessing the practicality of burning lime for agricultural use.  A small amount of lime is already in use here for processing leather and rawhide, as well as for preparing corn for tortillas and hominy.  Other uses will no doubt arise, such as the tree trunk paint formula I’ve been working on and all sorts of building and paint projects.   Another goal or motivation, as always, is to be able to share this information out to the end of providing achievable alternatives for small scale builders and self reliant tinkerers.  I am encouraged by the results so far and am looking forward to experimenting more.  I wanted to offer some insights gained up to this point, both for the benefit of people who want to try burning lime on their own and also just to have it written down for future reference.

LIME SQUAD! I: A Photoessay on Lime Burning

wood and shells in a carefully laid pattern meet heat and oxygen.

LIME SQUAD! I:  A PHOTO ESSAY ON LIME BURNING

LIME SQUAD! II:  THE SLAKING.

THIS BLOG IS RETIRED, I’VE MOVED TO SKILLCULT.COM   

ALL THE OLD TURKEYSONG POSTS ARE THERE AND MORE, CHECK IT OUT!

I’ve been interested in lime for a while now.  I use it in tanning hides and I want to use it in building.  Lime is also used in processing corn into hominy as well as masa for tortillas.  Doing things completely from scratch always interests me, so project buddy tonia and I set out to burn some lime and see just how much work and fuel is required for what results.  The following is a photo essay on our first lime burn, but first a few thoughts on lime, lime burning and lime users.

A BRIEF DESCRIPTION OF THE BASIC PROCESS

Limestone or shells (Calcium Carbonate CaCO3) are burned for a time until they are calcined, that is reduced to Calcium Oxide a.k.a. “quicklime” (CaO).  This releases carbon dioxide into the atmosphere.

The lime is now what is called quicklime and it is quick… quick to react with water in an intense chemical reaction creating heat and converting the lime to Ca (OH)2

To make dry hydrated lime, which is more stable than quicklime, the quicklime is sprayed with just enough water to cause it to undergo most of its reaction and crumble into a powder after which it is bagged.  Hydrated lime is used as an admixture to increase the workability of portland cement mortars which, even with the addition of lime, are horrid to work with.  Other people use hydrated lime as one would use lime putty that is mixed with water to form a lime “paste”.

To make Lime putty, the quicklime is mixed with a larger quantity of water whereupon the stuff boils like crazy and turns into calcium hydroxide, Ca (OH)2.  Lime putty remains as calcium hydroxide as long as it is kept from air under a cozy blanket of water.  Under water it only improves with age.

When the lime paste or putty is used it must be dried slowly. As the lime dries, it reabsorbs the Carbon which was driven away from it in burning back out of the atmosphere turning back into limestone (CaCo3) .  So, the lime putty is used wherever it is that you need limestone such as in mortar, lime concrete, plaster etc…  How cool is that?