Rock Island v.2.0 - Post #500!! - Ottawa Silica Sand Processing

Can you believe it?  We made it to post #500 on the blog!  Pretty exciting!

Here are some notes I took from the book "The Silica Sands of Ottawa".  Hopefully this will give you a better understanding of how the sand is processed.

Processing

Ottawa Silica has no need for mechanical crushers.  Each dynamite blast disintegrates the quarry’s sandstone into free-flowing banks of silica composed of thousands of tons of separate grains, just as the sand used to be, in its original state.  Any few remaining boulders are broken up by secondary blasting.    

After the initial blasting of the quarry face, jets of water under pressure stab into the banks of sand.  This does three things: it breaks up the few consolidated chunks of rock not completely disintegrated by the explosion, it gives the sand the first of many washings, and it forces the sand into a sump pit where it gets another cleansing. 

From here, powerful rubber-lined rotary pumps pipeline the sand to the main pumping station at the base of the refinery.  Here the sand is washed again.  In addition to the primary washings, the sand has been scoured and polished in the pumps and pipelines.  The sand is then moved into a large main washing plant.  A second washing is administered as the sand is discharged into a sump and is pumped into great draining bins.  Here is where the final washing takes place.  The sand is then left to drain. 

The sand is then conveyed from the drain bins to steam coil dryers by an overhead crane with a clam-shell bucket.  The steam and vapors from the drying sand pass off through the spaces between the pipes and baffles of the dryers and are vented out.  The sand works its way between the pipes, dropping below onto a continuous conveyor belt.  It is transported to the end of the building and elevated up and conveyed to the top of the refinery to the distribution screens. 

Ottawa Silica Sand is not ground to size for the hundreds of uses to which it is put.  It is screened to size, thus preserving the quality of the naturally rounded grains.  The grains are screened and graded by electrically vibrated screens with various sized meshes.  The vibrating machines comprise most of the mechanical equipment in the refinery.  It is elaborate, expensive equipment.  Each grain vibrates along the screen until it finds its particular mesh, and drops through into bins below.  Using this method a greater variety of grades is achieved and with flawless accuracy.

In summary, sand is washed, re-washed, scoured, polished, screened and then vacuumed. The sand is then shipped via rail using 2 and 3-bay covered hoppers.

Ground Silica Mill

No grinding is performed to effect sizing of grains.  Grinding is only done in the manufacturer of powdered silica.  It is ground to the fineness of confectionery sugar. 

Originally, the sand was ground with imported beach pebble from Danish and French coastal beaches.  Today, the grinding mill uses high-density aluminum-oxide balls to the grind the sand.  Although they are much more expensive than the imported pebbles, the new aluminum medium lasts longer, and does an even better job at grinding.

The powder product is stored in bins and bagged for market.

Some Uses of Silica Sand

·         Glass

·         Tableware

·         Sand-formed-and polished silver

·         Wall and ceiling plaster

·         Composition floors

·         Hand-washing products

·         Concrete

·         The safety in Safety Matches

·         Oil well fracturing

·         Furnace lining

·         Composition siding

·         Silicate of soda

·         Filter sand

·         Concrete improvements