Silicon and oxygen are the earth's two
most abundant elements and together they make silica, one of the
earth's three most common rock forming minerals.
Silica occurs in three main crystalline forms. The principal
occurrence is as the mineral quartz but it also occurs in other
rarer mineral forms known as tridymite and cristobalite. It is
a very durable mineral resistant to heat and chemical attack and
it is these properties that have made it industrially interesting
The first industrial uses of crystalline silica were probably
related to metallurgical and glass making activities a few thousand
years BC. It has continued to support human development throughout
history, being a key raw material in the industrial revolution
especially in the glass, foundry and ceramics industries. Silica
contributes to today's information technology revolution
being used in the plastics of computer mouses and providing the
raw material for silicon chips.
For industrial use, pure deposits of silica sand capable of
yielding products of at least 95% silica are required. Often much
higher purity values are needed. Deposits where such sand can
be found are comparatively rare in the UK.
|The main end uses of
silica sand are:
| Silica is the major ingredient in virtually
all types of glass. The principal glass products include containers
(bottles and jars), flat glass (windows, mirrors, vehicle
glazing etc.), lighting glass (light bulbs, fluorescent tubes,
etc.), tableware (lead crystal, drinking glasses etc.), TV
tubes and screens, decorative glass, fibreglass, optical glass
and vacuum flasks.
| Silica has a high melting point, 1610 degrees
C. This enables castings to be produced by pouring molten
metal into moulds made out of silica sand.
| Silica that has been ground to fine size
is an ingredient of most clay bodies and is a major constituent
of ceramic glazes. Typical everyday products include tableware,
sanitaryware, ornaments and wall and floor tiles.
| Closely sized grades of silica sand is
the principal filtration medium used by the water industry
to extract solids from wastewater.
|Specialist building applications
| The construction industry is founded on
silica and there are a host of specialist applications including
silica and aerated concrete blocks, floor and roof tiles,
flooring and rendering compounds, white line markings, roofing
felt and cement and resin injection systems.
|Sports and leisure
| Silica sand is used for equestrian surfaces,
in artificial turf, golf course root zones and dressings,
football and cricket and other pitches and as play sands.
| Silica has many other applications including
the manufacture of chemicals and metals, fillers in numerous
products, plastic and otherwise, the manufacture of refractories,
stimulating oil production and as additives in agricultural
and horticultural products. It is difficult to imagine a life
High grade silica sand is usually found as unconsolidated deposits
below thin layers of soil and overburden. After quarrying, the
sand often undergoes considerable processing before sale. The
processing may include washing and cleaning of the grains, sizing
to remove coarse and very fine fractions, and physical and chemical
processes to remove iron, chromium and other deleterious minerals.
After processing, the sand may be dried and some applications
require it to be ground in ball mills to produce very fine material.
A constituent body of MPA, the Silica and Moulding Sands Association
(SAMSA) represents the interests of MPA's silica sand producers.
Please contact SAMSA
for further information.
Please note this website is maintained
to provide information and guidance on UK issues, products and
applications of those products.