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Date: 14-12-2018
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Date: 19-10-2018
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Date: 20-12-2018
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Pure metallic tungsten cannot be obtained by reducing tungsten(VI) oxide using carbon, because it reacts with carbon to make tungsten carbide. Instead, the reducing agent is hydrogen. Powdered tungsten(VI) oxide is heated to temperatures in the range 550 - 850°C in a stream of hydrogen.
An excess of hydrogen is used, and this carries away the steam produced during the reaction. The hydrogen is dried and recycled. Great care obviously has to be taken to keep the whole system free of air to avoid explosion risks with the hydrogen at these high temperatures.
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دخلت غرفة فنسيت ماذا تريد من داخلها.. خبير يفسر الحالة
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ثورة طبية.. ابتكار أصغر جهاز لتنظيم ضربات القلب في العالم
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العتبة العباسية المقدسة تستعد لإطلاق الحفل المركزي لتخرج طلبة الجامعات العراقية
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