Kinetcis of silicothermic reduction of clacined dolomite in flowing argon atmosphere
The magnesium vapour extracted is removed using vacuum condition to condense as a dense metal. Thermodynamic analysis of this process has been carried out in the past to predict the distribution of the metal impurities in condensed magnesium. The results suggested that a number of impurities in different phases formed in the region between reaction zone and condenser. The thermodynamic results only are not sufficient to describe the process, and the knowledge of the kinetics of the Pidgeon process is required. Kinetics plays important role to give more insight to the process such as for process design and control.
Producing Pure Magnesium Through Silicothermic Under the Atmospheric Pressure
The majority of pure magnesium produced worldwide is made by using silicothermic method (Pidgeon process). However, the Pidgeon process suffers poor efficiency, low industrial concentration, and intermittent production. The main reason is that Pidgeon process requires to keep the reaction chamber in a vacuum state during the entire reduction process. By analyzing the thermodynamic reaction principle, we reveal that it is the low magnesium partial pressure instead of vacuum that is necessary for the silicothermic process. Based on this understanding, we develop a new technique that can produce pure magnesium under the atmospheric pressure by using silicothermic method. Flowing argon is used to carry away the magnesium vapor around the reactants, which reduces the local magnesium partial pressure. The magnesium production efficiency reaches 82.36% that is comparable to the widely used Pidgeon method, and high purity of magnesium with 99.97 wt% after melting is produced directly. The industrialized application of this exciting technique is expected to help the silicothermic to realize high efficiency, automated, and continuous production while at the same time completely change the poor production conditions, and reduce energy consumption and pollution.
Warm Hands in Cold Age – On the Need of a New World Order of Care
The world is aging as fertility and mortality are both decreasing. This article focuses on practical care work for the elderly. Such work is done primarily by women even though a larger portion than previously is paid rather than unpaid. All over the world, most elderly care work is organized within the family, most often unpaid. Men receive more care from partners than women, while women receive more care from female relatives. When care work is paid, the payment is generally low. A comparison between Germany, Spain, and Sweden demonstrates similar gender patterns, even though the role of the state in supporting care differs considerably as do care workers' conditions. The sustainability of today's distribution and organization of care work is questioned as the need for care increases, and the possibility of more equal sharing of care work between women and men is explored.