Safe Fly Ash?

To Powell River Legacy group:

Hi,

I've heard that fly ash can be safe and can in fact be used in building materials rather than be put into the ground. I understand however, that Catalyst barges and sorts their logs in the ocean thus contaminating the logs with fly ash which makes the fly ash toxic. Is this true? Do you know if Catalyst exploring these alternative options?

Catherine Coupe
Deer Lake, Burnaby B.C.

Reply 1 from the PR Legacy group:

You are correct in your information and your questions.

There seems to be many uses for fly ash which are generated as the result of burning coal, but so far there have been few uses found for the fly ash from burning wood products. The uses for fly ash found so far revolve around making the fly ash into a hardened / solid form which brings some integrity and strength to the product being made.

There are two separate methods to achieve this goal ---

---1) to add the fly ash in small proportions to the production of cement. This makes the cement more dense, more water proof and easier to flow into a form. This is a very common usage in the construction industry.

---2) to use fly ash as the main component in a mixture which is formed under very high pressure, and which is then cured in a moist environment. This is still somewhat new to the industrial process, but the brick that is formed is said to have a high degree of stability. The brick is not used for structural purposes, but mainly for veneers.

As mentioned, the fly ash from burning wood tends to be landfilled rather than reused. This is probably due as much to the attitude of the companies that burn the wood as to the fly ash formed from this process. The companies that burn wood tend to be pulp and paper companies who view the hog fuel they burn as a waste and keep that mental attitude intact when they look at the production of fly ash. There should be very little difference in the physical characteristics of the fly ash from coal or from wood.

The fact that the logs on the coast have been floated in salt water results in salt becoming an ingredient in the whole process. The presence of salt at the beginning of the combustion process results in there being salt in the fly ash (not desirable for cement) and in the formation of dioxins and furans in the fly ash as part of the combustion process. Dioxins and furans are formed at high temperatures when there is elemental chlorine [from the salt] and carbon [from the wood combustion] in specific conditions.

The pulp and paper mills are mandated by federal law to reduce their dioxin and furan emissions, and have improved their performance in the last few years, but it still is a problem. This could be avoided almost completely if no salt were added to the ingredients.

There is no safe level of dioxins and furans in our bodies.