Search results
Results from the WOW.Com Content Network
Underground mine ventilation provides a flow of air to the underground workers of a mine with sufficient volume to dilute and remove dust and noxious gases (typically NO x, SO 2, methane, CO 2 and CO) and to regulate temperature. The source of these gases are equipment that runs on diesel engines, blasting with explosives, [1] and the orebody ...
Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200 °C and 700 °C, the iron oxide is partially reduced to iron(II,III) oxide, Fe 3 O 4. 3 Fe 2 O 3(s) + CO (g) → 2 Fe 3 O 4(s) + CO 2(g) [9]
O–C–O: 180° , [3] decreasing to as low as 163° at higher temperature and/or pressure [4] Magnetic susceptibility: −0.49×10^−6 cm^3/mol Surface tension: 4.34 dyn/cm at 20 °C and equilibrium pressure Viscosity [5] of liquid at equilibrium pressure 0.0925 mPa·s at 5 °C 0.0852 mPa·s at 10 °C 0.0712 mPa·s at 20 °C 0.0625 mPa·s at ...
The required temperature varies both in absolute terms and in terms of the melting point of the base metal. Examples: Iron oxide becomes metallic iron at roughly 1250 °C (2282 °F or 1523 K), almost 300 degrees below iron's melting point of 1538 °C (2800 °F or 1811 K).
At a pressure of 1 atm (0.101325 MPa), the gas deposits directly to a solid at temperatures below 194.6855(30) K [2] (−78.4645(30) °C) and the solid sublimes directly to a gas above this temperature. In its solid state, carbon dioxide is commonly called dry ice. Pressure–temperature phase diagram of carbon dioxide. Note that it is a log ...
Calcination is thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O 2 fraction of air), generally for the purpose of removing impurities or volatile substances and/or to incur thermal decomposition.
The industry producing these gases is also known as industrial gas, which is seen as also encompassing the supply of equipment and technology to produce and use the gases. [1] Their production is a part of the wider chemical Industry (where industrial gases are often seen as "specialty chemicals").
Room and pillar mining was in use throughout Europe as early as the 13th century, [17] and the United States since the late 18th century. It is still in use throughout the US, [12] but has slowed or stopped entirely in parts of Europe. [17] Coal mining in the United States has nearly always operated with a room and pillar layout, although ...