*2.1.1 Materials*

The basic material used in these experiments is the original siliceous sand of the sand dunes of southwest Algeria. First, 100 g of dry sand was treated with 200 ml of hydrochloric acid over a period of 30 minutes at room temperature. Then, all the leaching tests were carried out in a 250-ml glass beaker placed on a magnetic stirrer with a control unit to ensure the homogeneity of the product at stable temperatures. When the required temperature (80°C) of the contents of the beaker (100 ml of acid) was reached, approximately 30 g of dry sand was added to the beaker while the contents of the beaker rotated at a constant speed of 250 rpm. The beaker was covered to avoid losses by evaporation. From the leaching solution, a sample amount of our prepared mixture was taken at predetermined time intervals, filtered, washed several times with distilled water to remove any unspent

### *Structural and Chemical Analysis of New Cement Based on Eggshells and Sand from Dunes… DOI: http://dx.doi.org/10.5772/intechopen.98346*

acid, and then dried at 110°C for 1 hour. All the experiments were repeated for more precision. The chemical composition of the silica sand prepared for this study was determined by X-ray fluorescence (XRF). **Table 1** presents the study results.

The eggshells were used as raw material to prepare the fly ash. They were washed first with distilled water and then with an acid solution (1 M HCl) to reduce the level of limine (CaO) and remove impurities. After drying, and when all moisture was removed, the material was calcined at temperatures ranging from 700–850°C after drying at 25°C. XRF analysis was performed to characterize the fly ash sample (see **Table 2**). It is evident that the sample is very rich in silica and eliminated, which makes it a suitable raw material to begin the geopolymerization process. The dimensions of the fly ash particles are less than 100 μm. The main element in pork roosters is CaO (63.69%).

Water glass, also called sodium silicate (Na2SiO3), was synthesized at the chemistry laboratory of Polymer Oran 1, University of Algeria. Then, 100 g of sand was washed with an acid solution (1 M HCl), dried at 25°C, and mixed with 200 g of sodium hydroxide (13 M NaOH). A platinum crucible was placed in an electric furnace at 850°C for 1 hour at a heating rate of 5°C/min. The mixture was melted, and the melt was cooled and solidified in the crucible. This method allowed us to synthesize 75 g of water glass nanomaterials (sodium silicate). This white powder was dried at 25°C to allow us to carry out microstructural, chemical, and mineralogical analyses.

Thermoplastic polyester (PET) has acceptable mechanical characteristics; in particular, a tensile modulus of elasticity of 2.89 GPa and a flexural modulus of elasticity of 2.36 Gpa, with a tensile strength of 58 Mpa and resistance to chemical attack. It is a semicrystalline polymer with a density melting point (specific gravity) of 1.28 to 1.39 g/cm3. The very fine grinding of plastic waste, such as drink bottles, gives us PET powder.
