Roasted watermelon seeds are consumed as snack foods. In this research, the Response Surface Methodology (RSM) was used in order to examine the effect of ROASTING on some physicochemical properties of watermelon seeds. The Central Composite Design (CCD) was applied to investigate the effects of two independent variables, i. e. temperature (180-260  C) and time (5-15 min), on moisture content, texture, color, total phenol, and antioxidant activity. According to the results, increasing the temperature and prolonging the duration of ROASTING caused reductions in the moisture content,  E and texture hardness. Meanwhile, the total phenol content and antioxidant activity increased. The linear, quadratic, and interactive effects between the independent variables (temperature and time) were significant on moisture content and texture hardness (p<0. 05). All variables, except the quadratic effect of time and the quadratic effect of the two independent variables, caused significant changes to the antioxidant activity and total phenol content. However, the total difference in color was only significantly affected by the linear effect of the two variables. Finally, ROASTING conditions (i. e. ROASTING temperature and time) were optimized in a manner that the acquired model-generated results akin to the experimental data (desirability=0. 74).

Red mud is an important solid tailing with strong alkalinity that is obtained during the extraction of alumina in the Bayer process. The global reserve of red mud is more than 4 billion tons, and its disposal as tailing has always been a serious environmental problem. This tailing is considered as a potential source, due to its high content of valuable metal compounds including iron. In this research work, the extraction of iron in red mud is investigated by the method of reduction ROASTING. The main influencing factors are also investigated. These methods include reduction in muffle and tube furnace, and temperature, reduction agent, and additive type are as important factors. Reduction ROASTING of the samples in a tube furnace, with Argon gas and vacuum, a mixture of red mud, graphite, and sodium carbonate at 700–1000 °C results in the formation of Fe3O4. Magnetic measurements indicate that saturation magnetization increases from 0.239 to 38.205 emu/g due to the formation of Fe3O4. Applying the magnetic field intensity of about 1000 Gauss results in the iron recovery of 89.9%.

Low-grade iron ores contain many impurities and are difficult to upgrade to make appropriate concentrates for the blast furnace (BF) or direct reduction (DR) technologies. In this study, the beneficiation of an Oolitic-iron ore (containing 45.46wt% Fe2O3) with magnetization ROASTING by non-coking coal (containing 62.1wt% fixed carbon) under a stream of argon gas was investigated. Then, a 2500 Gaussian magnet was used for dry magnetic separation method. The effects of ROASTING time, ore particle size and reaction temperature on the amount of separated part and grade of the product were examined. It was found out that the hematite inside of ore could almost be completely converted into magnetite by stoichiometric ratio of coal to ore at the ROASTING temperature of 625 °C for 25 min. Under the optimum condition, a high amount of magnetic part of the product (72.22 wt%) with a grade of 92.7% was separated. The most important point in this process was prevention of reduced ore from re-oxidation reaction by controlling ROASTING atmosphere, time and temperature. In addition, different analytical methods such as X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TG) and scanning electron microscopy (SEM) were applied to investigate and expound the results.