ALTERNATIVE RAW MATERIAL SOURES FOR CEMENT PRODUCTION

It is generally known that cement id produced from limestone, mar/clay and gypsum by the following three basic process- wet semi- wet aid dry process.

The cost of exploiting the limestone: the major raw material constitute about 50% of the production cost which results in the high cost of cement.  It therefore becomes imperative to bring down the cost of cement by investigating into alternative source of raw material for cement production and hence this project.

From literature, rice husk ash, Ukpo day,& Nsu day contain the basic mineral constituents which limestone has.  Rice husk was burnt temperatures of 5000c,   6000c,   7000c, and 8000c.  The best ash was obtained at a temperature of 7000c,.  the above material were also analyzed to determine their mineral constituents.  The result shown that rice husk contains little aluminum (Al203) and no lime (Ca0).  To make up for these mineral constituents, Upo day which is rich in aluming was blended with lime(Ca0)-a bye product from gas plant and the three minerals were blended using the method of lime saturation factor.  A blending ratio of 70% lime 20% PHA and 10% Alumina mixture (Ukpo day)  was used.  The mixture was mixed dry by dry process and burnt in a furnace at a temperature of 12000c.  the resulting mass known as dinker  was ground  with 5% gypsum.  The cement obtained gave a comprehensive strength of 2N/mr2.

 INTRODUCTION

1.1     BACKGROUND
OF THE STUDY

Cement is a complete mixture of mineral substances that
gradually harden when mixed with water. 
It is the product of the reaction of lime with the oxides of silica
alumina and iron.  It is used in the
construction of industry as a blending material.  Some builders regard it as the key
engineering material for construction purposes. 
many allied construction materials such as asbestos, culverts concrete
seals, concrete poles, cement blocks etc are derived from cement and they also
play very important roles in the construction industry. 

 

For the average Nigeria, a major life ambition is to own
a living house cement, a key raw material has ruined to ‘Gold’ as has become a
topical issue.  Just like iron, steel and
petrochemical, cement is equally a major spring board for
industrialization.  This quest for
industrialization has resulted to increase in demand with the consequent
increase in the cost of cement.

 

One of the reasons adduced for the exorbitant cost of
cement is the scarcity of raw material. 
This situation arises as  a result
of its fast depletion which is not replaced.

 

Another reason adduced for the exorbitant cost of cement
is the high cost of the exploration and exploitation of the raw material.  To mine the chief raw material for the
manufacture of cement- limestone requires a lot of machines, plants and
explosives.  A lot of money is also paid
as compensation to the communities that own the land.  All these expenditures lead to the high cost
of cement.  This study was therefore to
investigate alternative source of raw material for the production of cement.

 

These investigation was geared towards industrial waste
and Agricultural residues.  Agricultural
residues are composed of organic constituents such as cellulose, lignin, fibre
and small amounts of crude protein and fat. 
In addition, they contain a rage of minerals which silica, Alumina and
iron oxide.  The residue itself cannot be
used as cement replacement and it is the ash that is obtained form the preprocessing
that is of interest.  Two factors require
for constituents of the ash.  The ash
content is important because it indicates the amount of reside which need to be
burnt; that is the yield. D..J COOK (1980) states that rice husk have shown by
far the greater yieled of ash than other plants like sorghum, corn leaf blade,
Bamboo nodes, (Inner portion) bangasse, lantana leaf and stem and rice straw.

 

For every 1000kg of rice husk burnt, 200kg of ash are
produced.  Hence it is not surprising
that rice husk emerged as the agricultural that with the greatest potential as
cement replacement material.

 

One the other hand, lime is a by product of gas
companies.  It is readily available at no
cost.

 

The utilization of these raw material for cement product
production is very altercative in developing countries like ours.  This is because it does not only reduce
demand on Portland cement but it also provides cement in rural areas of the
country especially in rice growing areas which rice husk is found in large
quantities and constitute environmental nuisance.