Pyritic sulfur separation of El-Maghara coal ore was studied using Falcon concentrator model SB40-VFD as an enhanced centigugal gravity separator. The coal sample was ground to below 100 µm to reach liberation between pyrite and coal. Optimization of the separation process has been studied using central composite rotatable design (CCRD) and response surface method (RSM). The studied working factors were the back-water pressure (psi) and rotation frequency (Hz) and their interactions, where the feeding rate and pulp density were kept constant through all experiments. A model describing the relation between pyritic sulfur separation efficiency percentage and the previously mentioned operating variables and their interactions, have been designed. Results showed that maximum separation efficiency reached 70.61%, with decreasing total sulfur, and pyritic sulfur contents reaching 1.72% and 0.48% from original assays reaching 2.90% and 1.60%, respectively. That maximum separation efficiency was attained at 78.38 Hz rotation frequency (rotor speed 2282 rpm, 300 g) and 3.90 psi back-water pressure. The amenability of pyritic sulfur separation from the Egyptian coal using Falcon concentrator are determined. Technical difficulties within the separation process are highlighted.

Feed fractionation of a silica sand sample to a rare earth roll separator (RER) magnetic separator was found to be much more favorable for separation than the whole batch. The performance of the separator depends on both the size and the size distribution of the feed. The correlation between the different size fractions of the feed, e.g., −0.6 + 0.106, −0.6 + 0.211, and −0.211 + 0.106 mm and the RER magnetic parameters, e.g., belt speed and splitter angle of inclination was statistically verified using the central composite design (CCD) to achieve the optimum performance of the separator to reduce the Fe₂O₃ content of the sand concentrate. About 56.6% removal of this contaminant was achieved with the whole feed −0.6 + 0.106 mm at belt speed of 100 rpm and splitter angle inclination of 95°, whereas 84.3% reduction of Fe₂O₃ content was achieved with the separate size fractions under different belt speed and splitting angle inclination optima. The quality of the silica sand concentrate produced satisfies the requirement for both colorless glass and insulating glass fibers production.

A representative white sand sample was investigated for glass industry. Complete characterization of the sample was conducted. Chemical analysis of the sample showed that iron and alumina oxides reached 0.046% and 0.044%, respectively. Dry sieving was carried out to reject +0.6 mm and −0.10 mm fractions from the sample. The classified −0.6 + 0.1 mm product was directed to attrition scrubbing. The effect of pulp density, attrition impeller speed, attrition time and mode were studied. The attrition sand product was further subjected to gravity separation using “Wilfley” shaking table. Different working conditions of table separation i.e., sand feeding rate, stroke length, deck inclination, and dressing water flow rate were optimized. Results showed that the classified −0.6 + 0.106 mm sand product contained 0.039% Fe₂O₃ and 0.041% Al₂O₃ matched the specifications for the fourth-quality sand for sheet and plate glass industry. However, iron and alumina oxides contents were further decreased to 0.025% and 0.0164% after the attrition process. The attrition product accepted as second quality for flint containers and table ware applications. The final sand product after shaking table contained 0.0180% Fe₂O₃ and 0.090% Al₂O₃, was applicable for the first quality for optical applications.

Pre-shaped mesoporous amorphous rice husk ash (RHA) and MCM-41 derived from RHA as a silica source were transformed into MFI-type zeolites using two different structure-directing agents. Tetrapropylammonium hydroxide (TPAOH) was utilized as an alkali source for silica dissolution and structure control during the direct transformation of RHA into zeolite. A monopropylamine (PA)-containing alkaline solution (NaOH) was used for the pseudomorphic transformation of RHA or MCM-41 into zeolite. The hydrothermal conversion of RHA or MCM-41 into MFI-type zeolites was investigated as a function of reaction time at 175 °C. With PA as template, the crystallization took place inside and on the outer surface of RHA or MCM-41 without losing the original shape of the initial silica sources, while TPAOH led to the formation of conventional MFI-type zeolite crystals due to the complete dissolution of RHA. The final products were characterized by X-ray diffraction, nitrogen adsorption, scanning electron microscopy, and optical emission spectroscopy.

In this study, an Egyptian siliceous/calcareous sedimentary phosphorite was subjected to beneficiation by unsophisticated economic means. The mineralogical and chemical examination showed that the ore sample is a typical example for the East Mediterranean phosphorites with 21.80% P₂O₅, 10.93% acid insoluble and 16.61% loss on ignition. The primary crushed sample was classified into three size fractions without any milling and they were separately subjected to an integrated attrition scrubbing study. Screening and classification on the 2.30 mm and 0.071 mm sieves were sequentially introduced with the attrition process. The effect of solid%, attrition speed and time were studied and optimized for each size fraction. Results showed that three products were produced and could be categorized according to their P₂O₅ content into the coarse tailing (+2.30 mm), the attrition concentrate (−2.30 + 0.071 mm) and the phosphate fines (−0.071 mm). The P₂O₅ contents of these products reached 12.24%, 28.72% and 18.77%, with P₂O₅ distribution reached 6.74%, 51.75% and 41.51%, respectively. A global P₂O₅ of 28.72% was obtained with a recovery of about 52%. A tentative flow-sheet for the whole process was postulated.

Wet high gradient magnetic separation (WHGMS) of an Egyptian coal sample was carried out to minimize its pyritic-sulfur content reaching 1.60% (2.9% total sulfur). Optimization of the process using the Boxmag Rapid separator included feeding rate, pulp density, applied magnetic field, and the canister loading %. This was conducted through the CCRD and RSM, using Design Expert 6.0 software. Results showed that, at the optimum separation conditions, i.e., 10 l/h feeding rate, 5% pulp density, 2200 Gauss, and 0.6% canister loading, a coal concentrate assaying 0.57% pyritic sulfur was obtained with a recovery 58% and separation efficiency 79.34%.