“Characterization and Evaluation of Some Ornamental Stones - Processing Wastes at Shaq El-Thoaban Area (Southern Cairo) and Their Suitability for Some Industrial Applications”

Abstract

The continuous development of ornamental stones industry in Egypt due to the increasingly great demand of the Egyptian stones whether on the local or the international scale, led to a continuous and increasing accumulation of huge quantities of wastes in different forms which may reach about 55 – 85 % during all manufacturing stages. In the area of Shaq El – Thoaban only, about 70 % of these wastes is generating, which can be estimated as 800,000 tons of waste per year. These wastes have become of a hazardous effect on the surrounding communities due to the poverty of the wise management in recycling or even getting rid of these wastes in a safe mode. The present study aims at characterization and evaluation of some ornamental stones – processing wastes at Shaq El-Thoaban area (Southern Cairo) and their suitability for some industrial applications. This study throws light on the following items: 1. Industry of ornamental stones. 2. Characterization of ornamental stones wastes: 2.1. Physical properties. 2.2. Mineralogical composition. 2.3. Chemical analysis. 3. Preparation of cement composites using marble, granite and mixture of marble and granite wastes (on lab scale): 3.1. Mineralogical composition. 3.2. Physical properties. 3.3. Mechanical properties. 4. Industrial applications of marble wastes: 4.1. Manufacturing of concrete paving blocks: 4.1.1. Physical properties. 4.1.2. Mechanical properties. 4.2. Manufacturing of quicklime: 4.2.1. Available lime index. 4.2.2. Lime reactivity. The main findings of the present study are given in the followings: 1. Industry of Ornamental Stones: It passes through two stages: 1.1. Quarrying stage: This operation involves various stages: (i) Overburden Removal Stage; (ii) Extraction Stage. During each of these stages, huge amounts of stone fragments and powdered wastes are left around the quarry site depending on the technology owned by the quarrymen. 1.2. Processing stage: This operation takes place in the marble and granite processing plants in some industrial zones such as “Shaq El- Thoaban area” in Egypt, which involve slabs, tiles production with various dimensions through several stages which are: (i) Block Dressing Stage; (ii) Block Sawing Stage; (iii) Polishing and Slab Cutting Stage. 2. Characterization of Marble and Granite Wastes: Thirty five (35) samples of processing – ornamental stones wastes divided into: (25) marble samples and (10) granite samples were selected and characterized physically, mineralogical and chemically as follow:

2.1. Physical properties: 2.1.1. Particle size distribution: About 90% of the particles are of grain size 27.3μm for marble sludge samples, while for granite samples are of grain size 50.03μm. 2.1.2. Specific Surface area: The average surface area of marble sludge samples is about 0.6695 m2/g, while for granite sludge samples is about 0.4493 m2/g. 2.1.3. Specific gravity: It ranges from 2.66 to 2.74 with an average of 2.69 for marble sludge samples, while for granite sludge samples generated from block cutter discs it ranges from 2.58 to 2.64 with an average of 2.61, while that generated from gang saws it ranges from 2.77 to 2.78. 2.1.4. Water content (as received from factory): It ranges from 23.71 to 43.21 % with an average of 29.83 % for marble sludge samples, while for granite sludge samples it ranges from 29.38 - 48.05 % with an average of 38.64 %. 2.1.5. Whiteness index for marble samples: It ranges from (64.44 to 83.83 %) with an average of (76.89 %). 2.2. Mineralogical properties: The XRD patterns revealed that all marble sludge samples are mainly composed of calcite mineral, while that of granite sludge samples, whether by gang saw or by block cutter machines, are mainly composed of quartz and feldspars (Microcline and Albite) with traces of calcite.