biochar from driftwood?

I haven't made or used biochar, but I think I need to get my act together and give it a go
I live close to a beach that's continuously covered in driftwood, which would be by far the simplest way for me to access wood for biochar.
Does anyone have experience with using driftwood for biochar?
Or theories/thoughts why it's a good/bad idea?
I'm not very good at searching online- this was the only vaguely relevant reference I found.
It's super 'sciency', and is discussing fuel rather than amendments.
My main thoughts/questions are:
salt 1: I assume salt wouldn't hamper the actual charring process,
but I imagine the process would concentrate it?
I have high rainfall and sandy soil, so I'm not particularly concerned about salt build up,
but if the charring process creates little anti-microorganism salt bombs...
Maybe if I soaked the finished char to remove the salt, then added urine, compost tea etc?
salt 2: I assume it would corrode whatever burner I put together in no time, considering it would be from cheap/free materials-
no marine-grade stainless steel for me!

On a bit of a different track: NZ soils are very low in carbon and calcium.
The beach is also loaded with seashells, and I'm thinking of chucking some in when I make char.
It's illegal to remove anything but rubbish from the beach, but I can't see me starting a trend

Salt build up is not a problem in your sandy soil. It may help with some nutrient deficiencies. Driftwood from the ocean can do harm in dry coastal areas that are underlain with clay or where salinity is already high.

When wood is heated to high temperatures, the salt is likely to be separated into sodium and chlorine gas. This is what happens in wood fired kilns that use salt glazes. I would let the wood spend some time in the rain before charring it. Seaweed tea would be a good thing to soak it in. Everything plants need is found in the ocean.

--- Edit --- Don't char your shells. That's how quick lime is made. You lose the carbon and the product becomes caustic. It looks almost the same but it will burn your skin, eyes and plants.

For those who gather driftwood for hugelkultur. --- Most coniferous woods float. Most hardwoods sink. Thus the beaches are filled with mostly conifers in temperate zones. The best wood has sunk to the bottom.

You can char your seashells but not the way you're proposing. Try this - http://theunconventionalfarmer.com/recipes/calphos/ - instead if you want calcium phosphate.

Broken shells and driftwood are rubbish

"all things in moderation" There are people selling sea salt as a mineral supplement for compost tea. It is a good source for lots of trace minerals. You can salt the ground, but like Dale said it usually isn't a problem with sandy soils as long as they get rain. It can be a problem in greenhouses or under plastic mulch.

I don't know for sure about driftwood, but I charred an entire cedar roof that had to be replaced due to being covered with asphalt/fiberglass. I was skeptical so I kept the char in one corner of the property. That was this last spring and the growth there in that corner has been phenomenal. I am going to char all my scrap wood from now on.

When wood is charred, the volatile resins are burned off. Even awful stuff like pitch pine, can make perfectly good biochar. None of the allelopathic properties remain.

Illegal to remove things from the beach? Oops. Hopefully that's a Wellington thing.

I took a ute-load of seaweed, and assorted driftwood a few months back.

Good, I'm wasn't too worried about salt, but I know nothing about this biochar business.
I guess the thing with corrosion would be to go so basic, cheap/free that when my salty activities kill the er...retort...
I just whip up another.

Dale Hodgins wrote:Don't char your shells. That's how quick lime is made. You lose the carbon and the product becomes caustic.

Eek, thanks!
People have told me about cooking shells and bones, but they either left out the acid part, or have been quickliming their place for years
I'm not worried about losing the carbon, it's the calcium I'm after.

Mike Haych wrote:You can char your seashells but not the way you're proposing. Try this - http://theunconventionalfarmer.com/recipes/calphos/ - instead if you want calcium phosphate.

Cool
So I assume I could cook the shells aerobically in the (at this stage, hypothetical) burner, then do the acid thing?
They're pretty hard and would take some serious cooking.

Roger Taylor wrote:Illegal to remove things from the beach? Oops. Hopefully that's a Wellington thing.

Just on some beaches I think. I better check that!
Mine's getting the dunes etc restored so there might be extra rules.

Leila Rich wrote:

Roger Taylor wrote:Illegal to remove things from the beach? Oops. Hopefully that's a Wellington thing.

Just on some beaches I think. I better check that!
Mine's getting the dunes etc restored so there might be extra rules.

Ah, right, well no dunes here. Just stoney beaches where you don't want to go near the water if you want to live

Quick lime is a powerful base, not acid. I don't think that our eyes can feel the difference.

There's no need to process shells other than busting them up for finer particles. Seaweed is high in phosphorus. I gather kelp when it's at the half dry, sticky stage. Some parts of the beach are covered in finely ground oyster shells. The kelp is pressed into the dry shells and all is bagged. When spread on the driveway, it dries quickly. A lawn roller makes it into a nice granular mix that is easy to use. Lime and phosphorus, both in a natural, slow release form.

Burning driftwood or wood treated with salts as preservatives can form dioxins.

http://www.motherearthnews.com/homesteading-and-livestock/driftwood-and-wood-stove.aspx#axzz3FzULIp9a
http://en.wikipedia.org/wiki/Dioxins_and_dioxin-like_compounds#Sources

Leila Rich wrote: they either left out the acid part, or have been quickliming their place for years

Dale Hodgins wrote:Quick lime is a powerful base, not acid

that wasn't very clear of me-I meant they left out the part about adding acid

Welcome to permies Ravnor

Ravnor Chanur wrote:Burning driftwood or wood treated with salts as preservatives can form dioxins.

http://www.motherearthnews.com/homesteading-and-livestock/driftwood-and-wood-stove.aspx#axzz3FzULIp9a
http://en.wikipedia.org/wiki/Dioxins_and_dioxin-like_compounds#Sources

Well that's something new to consider
Hmmm. Now I need evidence that making charcoal from driftwood doesn't create dioxins!

Thanks!

I looked briefly, and most of the literature seems to deal with industrial-scale incineration and smelting - I didn't find any good resources for what the health hazard would be on a small scale like that. Compared to emissions from everywhere else, it's probably pretty insignificant, as long as you don't stand in the smoke.

If you could burn at a high enough temperature, that would solve the problem as well.