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29% P<sub>2</sub>O<sub>5</sub>Phosphoric Acid Desulphation: Improving the Performance of the Unit of Concentration

American Journal of Analytical Chemistry 2019年第3期10卷 65-75页

作者： Abderrahmane Aboulhassane Abderrahim Najah El Idrissi Yassine Bounou driss zakaria Laboratory of Physical Chemistry of Materials (LPCM) Department of Chemistry Faculty of Science Choua&iuml b Doukkali University El Jadida Morocco

Clogging in the heat exchangers of the phosphoric acid concentration unit is a phenomenon which hinders the proper functioning of the installation. It results in the accumulation of undesirable solid deposits on the pipes and consequently a decrease of its performance. This deposit is mainly anhydrous or hemihydrate gypsum in addition to Na2SiF6. Phosphoric acid desulphation before its concentration step allows reducing this undesirable effect. Barium carbonate is used for the retention of sulphate ions using a simple experimental protocol which can easily be inserted into the phosphoric acid manufacturing. Four factors: quality of the phosphoric acid to be concentrated, amount of barium carbonate, temperature and time, were studied using design of experiment (DOE) methodology with two-level full factorial design strategy in order to assess their effects on desulphation. Only the first two factors have significant effects. Therefore, for effective sulphate removal, the validated statistical model (R2 = 99.96%) allows to predict the amount of barium carbonate to be used, depending on quality of the phosphoric acid to be concentrated and using the available temperature and time in the industrial process.

关键词： Phosphoric Acid Barium Carbonate Desulphation Protocol Modeling Full Factorial Design

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Climate Change Trend Observations in Morocco: Case Study of Beni Mellal-Khenifra and Darâa-Tafilalt Regions

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Journal of Geoscience and Environment Protection 2018年第7期6卷 34-50页

作者： Ait Ouhamchich Kamal Karaoui Ismail Arioua Abdelkrim Kasmi Atika Elhamdouni driss Elfiraoui Fatima Ezzahra Arioua zakaria Nazi Fatima Nabih Nadia Earth Sciences Department Faculty of Sciences and Technologies Béni Mella Morocco Regional Meteorology Office Béni Mellal Morocco

Despite the extreme events impact on various climate events frequency and intensity in many developing countries, there has been dearth information on daily climate trends and climatic extremes. This study comes to characterize the climate type and its evolution in Morocco, specially the two regions Beni Mellal-Khenifra and Daraa-Tafilalt. RClimdex software has been used to calculate pluvio-thermal and ombro-thermic indices in the studied stations to reveal climate type in the two regions, their evolutions, and the daily extreme temperatures and precipitations. A cartographic representation has been done for the calculated indices and climatic trends in the stations from 1970 to 2016. As results, the temperature trend for hot day’s number shows a significant increase, while the cold night’s numbers, warm sequences, and precipitation are gradually decreases especially at Khouribga and Midelt. These observed modifications influence negatively the annual rainfall total in the year, the consecutive wet days, the maximums rainy days, and the increase of consecutively dry days. As a conclusion, the Martonne aridity and ombro-thermic indices, show that the temperatures and precipitations evolutions do not induce a change in the climate type for the studied regions.

关键词： Climate Trends Precipitation Temperature RClimdex Beni Mellal-Khenifra Daraa-Tafilalt

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