Ash - Chemical Composition and Physical Properties

balaguru1980

It really all depends upon WHAT you are burning to generate the ash...

hii...if i want to burn wood in a fluidized bed reactor to form ash as bed material,,what is the ash density in this case ??

There is always this as a start for fly ash.

http://en.wikipedia.org/wiki/Fly_ash

The whole purpose of this disscussion is to find out if we can use the ash as insulating material. May we can use the ash which is generated in the power plant. the second question here is that can this ash be solidified to be used as insulating material to withstand about 200 deg C. Thanks for your feedback.

In many cases, ash contains fixed carbon, silica, nitrogen and any metals not washed out during the chemical scrub. Carbon is very pourous and will absorb water and odour. If dry you can compact to thirty pounds per ft3 without much effort. A hydraulic press could give you sixty(???). If you use a binder it will probably make up 20% of the total material so remember to include the binder properties in your heat transfer calcs.

so can it be used for the thermal insulation purpose and what would be the disadvantage or difficulty in using the ash. Actually i want to use ash with some binder to use in a thermal canister as a insulator. thanks for your inputs.

You need permission?

I presume you are talking about thermal as opposed to electrical, insulation?. What you need to do is to evaluate the thermal insulating properties of the material and compare it with those from other available thermal insulation techniques, and decide what's best for you.

I'd guess there are many readers who would like to know how you get on, so please publish your findings.

Can readily withstand the temperatures you mentioned; however, use as an insulating material in homes could pose a problem unless the ash is encapsulated to prevent leaching of toxic substances if it encounters water.

The ash is totally encapsulated in the developed composites: ash doesn't migrate out as it has been tested using long-term ASTM tests by immersing samples in cold and hot water.

F.Shutov

Hi

The Company "Norwegian Talc" is fabricating small hollow silicate spheres for filling any suitable plastic or concrete. This is from coal fired power plant ashes.

This material will withstand easily temperatures above 1000°C.

Another material is from slags of the iron production being remelted and blown into fibres used for insulation.

RHABE

Thank you very much for this valuable inputs. i will go through that company website.

Hi,

any ceramic will be slightly electrically conducting at high temperatures, the worst insulators contain high amounts of alkali ions that have good mobility and thus generate ionic-conductance.

Look at the website of thermocoax, they fabricate heater elements insulated by highly compressed magnesium-oxide for low resisivity.

RHABE

i had one more doubt whether ash becomes conductive at any temperature.

Fly ash typically is not conductive and is often used in the manufacture of concrete. Think of how conductive concrete is, and that should give you an idea of the properties of ash.

i would add it to a polyurethane as a filler if weight is unimportant - PU ld be a binder and add R value http://www.edge-sweets.com they have equipment to handle solids

if weight is important then look up micro bubbles or phenolic spheres etc as others have pointed out

There is an industrial continuous process for production of porous plastic lumber based on my chemical composition which uses a considerable amount of fly ash (solid waste of power plant's industry) as filler, and commercial polymer binder (patent pending.) The final composites (boards with various cross section and any length) are effective heat/cold flux insulator in construction industry because of their controllable porosity and density.

Dr. F.Shutov

fshutov@yahoo.com

Ash is a very generic term. Can you specify what kind of "ash" you are interested in? Ash can mean anything from Fly Ash from coal-burning power generation stations to wood ash or even a specific kind of wood ash, and even ash precipitate by electrostatic separators.

composition of ash from coal burning or wood burning.