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.
DEFINITION OF TERMS
OPC - Ordinary Portland cement
LSF - Lime saturation factor
Quicklime - Calcium oxide Ca0
Raw meal - Secondary raw material that is fed into the kiln for burning
Raw mill - A tube like machinery where the grinding of raw material
ASTM - American society for testing materials.
Hydraulic modulus - The ration of lime (Ca0) to silica, Alumina and ferric
Clinker - Intermediate raw material and the product from the kiln.
C3S - Tricalcimn silicate
C2S - Dicalcium silicate
C3A - Tricalcium Aluminate
C4AF - Tetra calcium Alumiroferite
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.
1.2 PURPOSE OF THE STUDY
The present high cost of cement and the exorbitant cost of residential house occasioned by high cost of raw material exploitation, energy, population explosion and development have necessitated intensification into the search for alternative raw material for the production of this product. The aim of this project therefore was to bring down the cost of cement by the use of alternative raw materials form industrial and agricultural waste.
1.3 SCOPE OF THE PROJECT
The intention was to
1) Source and analyze the following raw materials rice husk lime (waste product from Niger gas company) Ukpo clay, Nsu clay and pulverized fuel Ash (PEA)
2) Obtain the best condition for preprocessing.
3) Compounding the raw mix.
5) Peterning the physical characteristics.
1.4 SIGNIFICANCE OF THE STUDY
On completion of the study, the result would be of importance to the Government and Entrepreneurs who may wish to go into the production of cement. The increased investments in this area will bridge the gap between demand and supply and bring down the cost of cement the reduced price of cement will catalyze infrastructure development and majority will be able to own a living house.
Another importance of the project is that it will serve as the starting point for the production of other types of cement known as blend cement. The study will also help to provide cement in rural areas typically of those traditionally deprived of cement. In this way small-scale businesses possible.
Since the industrial and agricultural waste are waste which causes environmental pollution and create problem with disposal its utilization would not only control environmental employment opportunities to our young school leaver.
The research would also be of immerse benefit to future researchers and student who would have the interest of studying similar subjects.