Sustainable Cement Utilization
[Enugu, Enugu State Nigeria]

In order to achieve the desired setting qualities in the finished product, a quantity (2-8%, but typically 5%) of calcium sulfate (usually gypsum or anhydrite) is added to the clinker and the mixture is finely ground to form the finished cement powder. This is achieved in a cement mill. The grinding process is controlled to obtain a powder with a broad particle size range, in which typically 15% by mass consists of particles below 5 μm diameter, and 5% of particles above 45 μm. The measure of fineness usually used is the "specific surface", which is the total particle surface area of a unit mass of cement. The rate of initial reaction (up to 24 hours) of the cement on addition of water is directly proportional to the specific surface. Typical values are 320-380 m2·kg-1 for general purpose cements, and 450-650 m2·kg-1 for "rapid hardening" cements. The cement is conveyed by belt or powder pump to a silo for storage. Cement plants normally have sufficient silo space for 1-20 weeks production, depending upon local demand cycles. The cement is delivered to end-users either in bags or as bulk powder blown from a pressure vehicle into the customer's silo. In developed countries, 80% or more of cement is delivered in bulk, and many cement plants have no bag-packing facility. In poor countries, bags are the normal mode of delivery.

2.4 IMPORTATION 13 plant owners and some other end users in the construction industry were granted licences to import the product. The benefiting companies including big players such as Dangote, Lafarge, Flour mills, Ibeto, Eastern Bulkcem and some new investors in cement production such as Quacem, Westcom , pure chem and Topcem. The approved grossed about 12 million xlv metric tonnes. With prices still high, government is considering issuing another round of licenses for cement import. But industry experts are calling for caution, saying begins as the palliative measures may seem, it could turn out an ill wind against local cement. It could be recalled that at in January 2008, President Umaru Musa Yar’Adua lifted the ban on the important of bulk cement into the country. Importation of bagged cement had remained banned. Though so many companies still campaign that importation reduces the cost of bagged cement. The government policy did not achieve its end-view because it provided perverse incentives to the industry operators. The government banned importation licenses for eight metric tonnes of bulk cement. Since commencement of local production of cement in Nigeria in 1957, local production has never been able to meet demand, ever in the mid-80s when demand of cement was declining. Local production has remained at less than 50 per cent of total installed capacity, which is largely concentrated in just two plants. xlvi Of the annual demand estimated at 18-million tones, local production can only supply between 6 and 6.5 million tones of cement yearly. The current policy, no doubt, is aimed at bridging the deficit 11.5 million tones in the supply of cement, and temporarily reduces prices which have increased by over 300 per cent since 1999. The cement industry contributes to the economy in various ways. As a major input provider, it provider linkages to other sectors of the economy, especially building and construction. These potentials are yet to be seen in recent cement firms in Nigeria, has not had the desired effects despite the huge concessions made by the government to the new private investors. It is now obvious that the promises of new investments are nothing other than expansion of packaging facilities. The government while announcing the lifting of the ban on the importation maintained that the new policy would rejuvenate the cement industry , bring down the exuberant price of cement stabilize supply and encourage investment. How ever, the extent to which they can do so efficiently depends largely on the incentives underlying government polices as they affect local production, distribution and pricing. xlvii License or quota –based importation in whatever form effectively limits the powers of the market to operate effectively, it creates distortions and diverts resources allocations. Through this policy may actually work against itself.

2.5 SHORTFALLS IN CEMENT INDUSTRY The challenge of cement production in Nigeria includes the problem of power supply, gas supply, especially distribution network as well as infrastructure development. Most importantly bringing down the price of cement to 1,000 per bag as said by the then minister of commerce and industry, Chief Achike Udenwa. The professionals in the built environment have doubted the realization of this challenge, they said, this was only going to be possible if the basic incentives such as tax holidays, infrastructure and other fiscal measures like reduction in duties and tariffs, as well as putting in place policies that would encourage the growth of the industry and give the manufactures valve for their investment. It is not enough to ask the producers to reduce prices without putting the right and conducive environment in place if the federal government has xlviii now found that the price is a serious macro- economic issue, it should intervene directly through fiscal measures in form of all taxes and duties reduction to encourage producers. If Americans that is regarded as the bastion of capitalism can adopt the Keynesian model, we have to strengthen our fiscal measures and fiscal policy as intervening in other sectors. The government needed to declare the machinery it wanted to commit to the realization of the reduction of cost of cement or the package it had in place. The government would need to give good incentive to the sector and declare a state of emergency on the power sector because it was key to the manufacturing sector, if not we shall be chasing shadow.

2.6 USE OF LOCAL MATERIAL FOR CEMENT PRODUCTION The need for the utilization of locally available indigenous materials such as pozzolanas, bamboo, oil palm fibers, coconut core fibers, palm kernel shells, coconut shells, periwinkle shells, laterite etc, which are readily available in Nigeria, and with great practical value for the provision of affordable housing for all; a vision so dear to the Nigerian is very important. xlix Nigeria’s economic potential is well known and recognized internationally. Notwithstanding, Nigeria is yet to realize this potential and much is still desired before the vision 2020 – ‘Housing For All’ can be attained. To attain this goal, the country will need to enhance her economic performance, scored on many key parameters among which are infrastructure. The importance of the provision of adequate housing for all by year 2020 cannot be over emphasized. Checking scarcity and high cost of building materials and the need to drastically reduce critical housing shortages, especially in the urban areas and developing modern As at December 2007, manufacturing capacity of six major producers of cement in Nigeria equals 8.46 million metric tone

2.6.2 CEMENT PRODUCTION Total consumption of cement in Nigeria as at December 2007 equals 11.125 million metric tones. Of the total consumption of cement in 2007, local manufacturers accounted for 42.5% (4.725 million metric tones) only while imports accounted for 58.5% (6.4 million metric tones)(Ikponmwosa 2008). l Alternative, innovative and cost effective building materials. Utilization of readily available indigenous biological materials such as oil palm fibers has great practical value and potential. Controlled utilization of alternative materials to cement should be encouraged in construction as this will result in high economic value. Exploration of abundant naturally occurring materials such as bamboo, coconut fiber, sisal and oil palm fiber is needed in developing countries to reduce cost of construction and low cost housing. Rising level of pollution in construction industry calls for adoption of “Eco-structures”.

2.6.3 POZZZOLANAS Pozzolanas are materials containing reactive silica and/or alumina, which on their own have little or no binding property but, when mixed with lime in the presence of water, will set and harden like cement. They constitute an FIG.11 Chart for Constituent Materials for Low-Cost Housing lii important ingredient in the production of alternative cementing material to Portland cement (OPC). Pozzolanas have been used to partially replace cement in concretes in some countries like Malaysia, Singapore, Brazil, China, India, etc.

2.6.4 GENERAL INFORMATION With a few notable exceptions such as Indonesia, Oman, India and China, the commercial exploitation of pozzolanas in the Third World has generally been slower. In recent years there have been project to develop pozzolanas in several countries, including Kenya, Tanzania, Cuba, Trinidad and Dominica. Research and pilot projects have been undertaken in most of the major rice-growing countries of the world.

The National Building Research Organization (NBRO) in Sri Lanka has investigated burned clay pozzolanas with emphasis on mineralogical analysis of different clays found in Sri Lanka, subjecting them to a range of different burning regimes, grinding the clays and separating out different size fractions before carrying out tests for pozzolanicity and compressive strength of mortar cubes. Rice husk ash cement production facilities have been developed locally in a rural part of Moneragala district of Sri Lanka. liii In Cuba, alternative binder on the basis of pozzolanas from agricultural waste and lime is now being produced in around 160 small workshops spread over the country. The total production of these workshops has already passed 20,000 metric tones, but there is a potential for increasing that substantially.