In the present study, the kinetic modeling of monosodium phosphate to sodium- hexametaphosphate reaction is considered in a micro-reactor. The corresponding experiments were carried out at 650-730oC in different resident times and the experimental data i.e. monosodium phosphate conversions were recorded. A power law model equation was chosen as kinetic rate equation and the equation’s parameters were estimated from experimental data using genetic algorithm method. The comparison between the experimental data and model predictions showed that the presented model has a good agreement with experimental data with average absolute relative deviation of 3.39%.

The adsorption of lead (11) and copper (11) in a fixed bed column using activated carbon prepared from nipa palm nut was investigated. Thomas model and Yoon and Nelson kinetic models were used to analyze the column performance. The rate constant for Thomas model increased with increase in flow rate and initial ion concentration but remained constant at varying bed height. Adsorption capacity for the adsorption of copper (11) obtained from Thomas model ranged from 3.417 to 17.224 mg/l for Thomas model and from 3.02 to 11.92mg/l for Yoon and Nelson model. Also the adsorption capacity for lead (11) adsorption calculated from Thomas model ranged from 6.937 to 75.59 mg/l and from 12.10 to 47.24 mg/l for Yoon and Nelson model. The maximum adsorption capacity increased with increase in flow rate and initial ion concentration but decreased with increase in bed height. For Yoon and Nelson model, the rate constant increased with increase in flow rate, initial ion concentration and bed height. The time required for 50% breakthrough decreased with increase in flow rate, bed height and initial ion concentration. The kinetic data fitted well to both models. The comparison of the experimental breakthrough curves to the breakthrough profiles calculated by Yoon and Nelson method showed a satisfactory fit for activated carbon prepared from nipa palm nut.

Iran is rich in mineral resources such as Celestine. On the basis of estimations, the capacity of mineral Celestine is over two million tons with 75-95% strontium sulfate purity. Strontium sulfate directly is not a major feed in industries, but it has a huge consumption in the form of strontium carbonate in many industries such as Color cathode Ray Tubes (CRT), pyrochemical process, ceramics, paint production, zinc purification process. Two conventional methods are used to produce strontium carbonate from strontium sulfate including direct reaction method and black ash method. In this work, the second method was analyzed and optimum condition of many operational condition and process parameters were determined. In the black ash method, firstly, mineral Celestine was reduced with coke at high temperature and strontium sulfate was reduced to strontium sulfide. In according to high solubility of sulfide in hot water, strontium sulfide was separated by leaching process. Then, strontium sulfide was reacted with sodium carbonate and strontium carbonate was produced. One isolated system was designed and prepared properly to analyze operational condition and process parameters including process temperature, residence time, feed particle size distribution and the effect of excess coke on conversion. The results showed that the reduction reaction occurred for temperature more than 800 °C. Also, smaller particle size led to better reaction conversion which is related to more surface provided. It was found that using more than 20% excess coke in the process, increases the efficiency by 4%. However, using more than 25% excess coke has not any positive effect on reaction process and conversion. Mass transfer resistance analysis showed that the most important resistance to reaction is diffusion throughout black ash layer which is controlling phase to reduction reaction. Thus, black ash layer is the most important parameter to control the rate of reaction. Finally, optimum condition is determined at temperature 1100°C, residence time 2 hours in reduction furnace, particle size distribution including coke and Celestine substance in 100 to 500 mesh, excess coke 25% with 75% reaction efficiency and high reliability and economical explanation.