Think of fly ash as a filler. Think of those products that have fillers with similar properties. Ask yourself or research and become informed on what fillers do.

Is the filler a bulking agent or active ingredient? As a bulking agent it is basically inert and simply adds volume for little cost or an active agent that adds integrity.

Can fly ash replace another more expensive ingredient? Then relook at 2nd statement such as:

1. cement - as you noted

2. paint and paint like filler products

3. plastics fillers in PC boards

4. polymer fillers in general such as rubber

5. Road base fillers in asphalt

6. other cement like products where fillers can be activated

Fly ash is a silica. What other silica fillers are manufactured and for what products? There is a large list.

Not all fly ash products are equal. There are great differences in shape, size, surface geometry, activated surfaces, degrees of impurities that help or hinder. ■

Fly ash is a pozzolan ie has cementitious properties

Hence, its main use is in

cement - fly ash blend

road and landfill stabilising

The best fly ash is that which has low ash and is round in shape eg from black coal power stations.

Use can get 25% cement substituion with fly ash in AFb cements - hence, good product with less processing costs.

As fly ash is very fine in size, it make a very good intersitial filler and hence, for concrete works, produces a good finishing/workable concrete with higher impervability

There are other uses but these are the main ones.

Cheers

James ■

James,

Knowing your preference for the cement industry based fly ash, have you seen or explored the benefits or detractions of the many forms of power plant fly ash such as:

1. star shapes (non-spherical)

2. solid spheres

3. hollow spheres

4. hollow spheres with surface holes

5. Agglomorates of spheres

Do you care about shape?

Hollow shell thickness variations can be from solid spheres to spheres with walls that are about 1/10 of particle diameter. How does this affect your preferences?

What about sensitivity to diameter, ranging from medium microns down to small submicrons? Or stated in another way, what is the preferred size range of cement additives?

How do you deal with the calcium carbonate? Is this liming agent your principle interest?

Fly ash is being studied as a means to lower the acid level in soils. It does trend to reducing plant products in the first year. There after significant improvements are noted.

In the USA, about 60 % is not usable and about 50% of usable fly ash is applied in cement. THis may be going down due to the need to lower NOX. Apparently, this adds unacceptble unburned carbon to the fly ash mix. ■

Larry

I am sorry but U asking questions outside my realm, fly ash is handled by our subs. company, at site we export it down south (where they do not have the same type of fly ash) plus make FAB cement.

Our locally sourced FA is 5000 Blaine - 5000m2/kg of surface area. Hence, do not need intergrinding for cement.

Consistency is the key for end users/market.

As U can tell freight costs are high cf product costs...logistics is vital

There are small operators in the FA market here with specialised markets but the volumes are too small for us to muck around in this - we do help them out with technology and "farmer craft" equipment.

I beleive that some are setting up business in Asia as well.

U will find that the source can produce much more than the alternative market can take - hence, there is on site FA treatment and tailings at most power stations.

Cheers

James ■