J. Appl. Sci. Environ. Mgt. 2005 JASEM ISSN 1119-8362 Full-text Available Online at All rights reserved http:// www.bioline.org.br/ja Vol. 9 (1) 65 - 68 A Preliminary Evaluation of Otamiri River Sands for the Production of Plain Glass * USHIE, FA; **ESU, EO; *UDOM, GJ. * Department of Geology, University of Port Harcourt, P. M. B. 5323, Port Harcourt, Nigeria. **Department of Geology, University of Calabar, Calabar, Nigeria. Email [email protected] ABSTRACT: Grain-size distribution and chemical analyses were carried out on four sand samples randomly taken from the bank of Otamiri River around Chokocho and Umuanyaga, Etche Local Government Area, Rivers State. This was done to assess the purity and suitability of the sands for the making of plain glass. Results of grain-size analysis show that 86% of the sand particles fall between 0.125mm and 1.2mm, which is within the ideal sand fraction range used for glass making. Chemical analysis shows the sand to contain more than 99% silica (SiO2), very low content of iron (0.0017 to 0.0039ppm), chromium (0.000022 to 0.000032ppm), titanium (0.049 to 0.066ppm) and calcium (0.000001 to 0.000003ppm). Others include Aluminium (0.00126 to 0.0103ppm), potassium (0.0002 to 0.0042ppm), Magnesium (0.0001 to 0.0002ppm), and Sodium (0.005 to 0.038ppm). The concentration levels of these elements in the samples conform with internationally acceptable standards for glass production. @ JASEM The most important constituent of glass is silica town to join the Imo River in Etche LGA, Rivers (SiO2). Glass sand contains between 95-98% silica State. It receives tributaries along its course and (Hutchin and Harrington, 1966; Sempolinski and drains a considerably large area. By this action, the Schermerhorn 1997) Other constituents are Coastal Plain Sands (Benin Formation) are constantly impurities in various concentrations (Hrdina, 1999) washed as the river flows southwards. which are useful in determining the kind and colour Etche LGA lies within the Benin Formation of glass to be made. On the other hand, in the of Oligocene to Miocene age, which is part of the production of ultra-low expansion (ULE) glass, stratigraphic column of the Niger Delta Sedimentary impurities are rather minimised by injecting high Basin. This Formation overlies the Agbada purity precursors into flames which then react to Formation consisting of sands with shale form TiO2 and SiO2 which deposit into the surface of intercalations, and is prominent as the major the growing glass (Hrdina, 1999). petroleum reservoir in the Niger Delta sub-region. To obtain a homogeneous melt the grains of Underlying the Agbada Formation is the Akata silica sand should be of even size between 0.12 – Formation, mainly shaly, which is the major source 2.00mm (Glass Production Guide, 1966). This paper rock for petroleum in the Delta (Short and Stauble, seeks to evaluate the sands using the data arising 1967). from grain-size and chemical analyses in order to Basically, the Benin Formation consists of determine their suitability for glass making. The over 90% sands and sandstones, which are gravelly grain-size analysis helps to determine the grading of in places with a maximum thickness of 2130metres the sands; because for a homogeneous intersolution (Schield, 1798). There are shale intercalations within to be produced, the sand must be even in size and this these sands/sandstones at some levels. The sands are is known as the “ideal fraction”. The chemical fine-to-coarse-grained in size, granular in texture and analysis on the other hand helps to determine the hardly consolidated. The sediments represent upper purity, hence the type and colour of the glass to be deltaic plain deposits; the sands may represent produced. braided streams, point bars and channel-fills, whereas the thin shale intercalations may represent back- Physical/Geological Setting Of The Study Area: swamp deposits. In the subsurface it is Oligocene in The study area is in Etche Local Government Area of age, becoming progressively younger southwards Rivers State, Nigeria. It lies between longitude 6045' (Kogbe, 1976). and 7018'E and latitude 4045' and 5015'N (Fig. 1). The study area is within the subequatorial region which is Data Acquisition characterized by two major seasons namely, the rainy Four sand samples were collected from the Otamiri season and the dry season (Iloeje, 1972). The rainy River around Chokocho and Umuanyaga season starts in March and ends in October, with a communities in Etche L.G.A. (Fig. 1). A grab was peak in June and July, while the dry season begins in used to collect the samples from the river banks and November and lasts till March. Annual total rainfall exposed river sections. The samples were then is over 200cm, relative humidity is above 80% and subjected to two methods of analysis to generate the the mean temperature value is 28.140C in parts of the needed data. state (Udom et al 1999). Otamiri River takes its rise at Egbu in (a) Grain-Size Analysis Owerri area and flows southwards through Owerri *Corresponding author Email: [email protected] A preliminary evaluation of otamiri river sand… 66 Grain-size analysis was undertaken to determine the sieving the samples through standard set of sieves. ideal fraction of the sands. This was done, first by The results are shown in Table 1. TABLE 1: Result Of Grain Size Analysis Sample Percentage passing (mm) D10 Cu Cc number 2 1 0.425 0.125 0.075 0.063 1 93.82 78.07 36.87 0.70 0.15 0.08 0.220 2.95 0.01 2 92.33 81.48 43.75 1.24 0.95 0.06 0.185 2.98 1.14 3 87.35 69.92 29.74 0.85 0.53 0.09 0.24 2.98 1.07 4 96.09 83.53 57.70 2.31 0.83 0.51 0.170 2.80 1.05 Thereafter, the results were plotted on conventional 16 hours the solution was heated in a water bath until graph papers to identify the ideal fraction and it was clear. Two grammes (2g) of boric acid was uniformity coefficient (Cu) of the sands. Cu is given added to prevent the precipitation of Ca and Mg by the formula. fluorides. The solution permits the determination of D silicon, titanium, alumunium, iron, calcium, Cu = 60 magnesium, sodium and chronium using the Atomic D10 Absorption Spectrophotometric (AAS) method. For this study the Buck/Scientific AAS 200A was used. Where D60 = diameter of the 60th quartile and The prepared aqueous solution of the sample D10 = diameter of the 10th quartile was analysed for elemental constituents by choosing A typical grain-size distribution plot the wavelengths of the elements and determining the (representing sample location 4) is presented response of the elements when compared with the in Fig 2. concentration of the standard solution. The standard control value of each element is shown in Table 2. (b) Chemical Analysis The results of the elemental constituents of the 500mg of the sample was ground, prepared samples are shown in Table 3. and left for 16 hours with ocassional agitation. After Table 2: Control Value Of Each Element Element Wavelength (nm) Flame gas Sensibility Si 251.6 NAC 85 Ti 365.3 -do- 85 Al 309.3 -do- 45 Fe 248.3 AAC 6 K 766.5 -do- 1.8 Mg 285.2 AAC 0.3 Na 589 -do- 0.7 Ca 422.7 NAC 0.05 Cr 357.9 AAC 4 AAC – Air Acetylene NAC – Nitrous Oxide Acetylene Table 3: Results Showing Elemental Concentration Of The Sand Al Ca Fe K Mg Na Cr Ti SiO2 SAMPLE ppm % NO. 1 0.00126 0.000003 0.0017 0.0002 0.0001 0.005 0.000024 0.049 99.1 2 0.0062 0.000001 0.0039 0.00025 0.0001 0.025 0.000022 0.064 99.3 3 0.0015 0.000002 0.0017 0.00025 0.0001 0.01 0.000032 0.059 99.5 4 0.0103 0.000002 0.0032 0.00042 0.0002 0.038 0.000026 0.066 99.0 Mean 0.0048 0.000002 0.0026 0.00028 0.00013 0.020 0.000026 0.060 99.2 Std. 0.004 0.0000007 0.0010 0.000083 0.00004 0.013 0.000004 0.007 0.19 Deviation Stipulated > 95* Standard * Hutchin and Harrington (1966). Ushie et al A preliminary evaluation of otamiri river sand… 67 DISCUSSION AND CONCLUSION The results of grain size analysis (Table 1) and the resulting distribution curves for the sands show the coefficient of uniformity in the range of 2.80 to 2.98. It is obvious from these values that all the samples exhibit a high degree of uniformity. Also about 86% of the sand fall within the ideal fraction (0.125- 2mm). This is suitable for glass making (Glass Production Guide, 1966). Chemically, the sand that can be used for glass manufacture must have a minimum of 95-98% silica. It is clear from the results of the chemical analysis (Table 3) that this important chemical requirement is met. The high percentage of silica in the sand transfers qualities like high electrical resistance and high softening temperatures to the glass. The results of this analysis show the presence of Iron, Chromium and Titanium with mean values of 0.0026ppm, 0.000026ppm, and 0.060ppm respectively. These elements are capable of producing different colours in glass. However, their concentration levels in the samples show that the manufacture of colourless glass is possible. If necessary, decolourizers can be used. On the other hand, if coloured glasses are needed, colouring agents can be added.