Spinel (MgAl2O4) containing high alumina refractory cements are in high demand by the glass, cement and metallurgy industries. Spinel-based cements improve thermomechanical strength and minimise slag attack. In addition they can give outstanding improvements to lining life when compared with other refractory materials.
Spinel cements are normally produced by a sintering process starting with synthetic spinel and high alumina content cements. The problem with this is the high cost of sintered and electrofused spinel raw materials. A solution to this is to generate the spinel phase in-situ when making the refractory materials from active alumina and high purity dolomites.
Recent work from Araceli Elisabet Lavat and María Cristina Grasselli from Universidad Nacional del Centro de la Provincia de Buenos Aires seeks to better understand this potential new processing route.
The research work, published under AZojomo* (OARS)**, seeks to establish the feasibility of application of Agentinian dolomite raw materials in preparing refractory cements. The starting materials were fully characterized for particle size and chemical and mineral composition by laser granulometry, fluorescence, X-ray diffraction (XRD) and FTIR techniques.
The phase changes during cement synthesis up to 1450°C were studied by the combination of XRD and infrared spectroscopy. The research found the optimal temperature for an in-situ spinel formation was 1450°C.
Dr. Ian Birkby | EurekAlert!
New biomaterial could replace plastic laminates, greatly reduce pollution
21.09.2017 | Penn State
Stopping problem ice -- by cracking it
21.09.2017 | Norwegian University of Science and Technology
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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