Ned,

Stockpile management is most probably your best bet. I dried out moist sand in a couple of days under Java sun. Although not a completely reliable source.

Indonesians universally dry wet rice by spreading it in the open air. When it is going to rain they cover it with light duty tarpaulins. I'd consider doing similar with sand rather than go to much expense with a dryer. Just how big is your stockpile in the first place? Have you done any, timed, solar tests?

Nature can be on your side at times. I remember when RAK ROK, probably the largest quarry in existence used to stack cement clinker in the open air along the Persian Gulf coast. When the intense, but short, rains came along the water dried out next day and a hard waterproof skin formed over the pile. That skin was broken at the base by wheel loaders and reclaim carried on normally. They've now come into money and built a big old shed for no reason. Can you cover the pile with your geopolymer and let it set the same way?

As a raw Pom I tend to think of Oz as essentially dry hard pitches. You will be able to reduce the moisture while the sand is stockpiled and, at worst, supplement the drying with a smaller, cheaper dryer. ■

John's proposal for drying by solar heat is a good economic way to dry sand. Just calculate carefully the required surface area, which seems to be at least about 1000 square meters and a need of a big storage pile to take care of rainy periods. You may need also a simple way to control the moisture content while handling it to intermediate storage. I recommend an optical moisture content sensor, not the expensive conventional ones, but one designed just for your purpose with a solid state design having nor wearing of moving parts and can be used continuously over a belt.

Taisto Haavasoja

www.teconer.fi ■

Originally Posted by ned6

Hello all,

We are investigating options for sand drying for production of a geopolymer concrete product here in Australia.

Basic parameters are:

- sand supplied moisture content 6% to 9%

- sand target moisture content 3.5%

- throughput 37 tons per hour (250 tons per day)

Capital is limited, so fluid bed dryers look too expensive, as do locally supplied rotary dryers.

Any experience on here with Chinese manufactured rotary dryers?

Any alternative methods, i.e. stockpile management, to get sand this dry?

Thanks,

Ned

===========================================================================================

Not really pig in poke or a muddy cricket or soccer pitch.

That amount of sand in a stationary dryer is a bit of an

issue but not insurmountable.

You have to keep in mind that the heat is going to attract

moisture like a magnet at night so the lower moisture

desired target will be an issue.

What you/want/are looking for is burned sterilized sand-which is

also white golf course sand.

The issue is both throughput and fuels.

Golf course sand makers have a hopper with a baffle plate to split

the wet sand, then a low speed auger moves the wet sand at slow

rate to the trommel screen separating the fine sand from the

debris in the fine sand.

The sand is carried up and down by catch plates inside the rotary screen

and then the sand is burned/heated by a propane burner then falls on to

a small take a way conveyor to a pile by the sand burner.

Short of building a set of five sand bins that will have 250 tons each that

are heated by a number of coal fired hot air furnaces or one large one with

ducting under every bin that travels under the floor of each bin to the next bin

to continue heating the sand while the first batch is dried out completely by

turning white.

Unless the sand is white from burning you will not know it is dried completely

and ready to be moved to storage.

You also going to need a large number of dehumidifiers if your dumping it on the ground.

You will have blow the sand into a battery of gravity sand/cement silos to keep it that dry.

The other thing is how or whether are you going to be able to keep and move 3 carloads

of sand dry to the end user as soon as its ready to be sent to the mix plant? At 22 tons a load

that is going to be 11 loads of dried sand per day being fed into 11 vacuum tankers or 55 loads

per week.

From what I have seen on Chinese flail mowers, the poor weld quality and design is suspect

so that is all I can comment on.



=====================================================================================

Short of a good quality paddle drier and a forced air or steam to forced hot air heat source with return plenum

to the furnace I think you are stuck.

A paddle drier will have the ability to dump into a battery of gravity cement bins or directly into

covered hopper cars as long as one hundred ton batches are cooked in 33 ton batches to assure

even loading in a covered hopper car that has 3,000 cubic feet of capacity. ■

Originally Posted by lzaharis

==

.....

What you/want/are looking for is burned sterilized sand-which is

also white golf course sand.

The issue is both throughput and fuels.

...

"We are investigating options for sand drying for production of a geopolymer concrete product here in Australia.

Basic parameters are:

- sand supplied moisture content 6% to 9%

- sand target moisture content 3.5%"

Are these the same product? Ned, what method did you use in the end? ■

Gidday,

A fluid bed would be a good choice. Please check out www.ibulk.com.au

Carrier has extensive installations drying sand all over the world.

Cheers!

Originally Posted by ned6

Hello all,

We are investigating options for sand drying for production of a geopolymer concrete product here in Australia.

Basic parameters are:

- sand supplied moisture content 6% to 9%

- sand target moisture content 3.5%

- throughput 37 tons per hour (250 tons per day)

Capital is limited, so fluid bed dryers look too expensive, as do locally supplied rotary dryers.

Any experience on here with Chinese manufactured rotary dryers?

Any alternative methods, i.e. stockpile management, to get sand this dry?

Thanks,

Ned

■