Calcium oxide

About: Calcium oxide is a research topic. Over the lifetime, 7600 publications have been published within this topic receiving 66104 citations. The topic is also known as: caustic lime & quicklime.

Evaluation of Moisture Susceptibility of Asphalt Mixtures Containing Bottom Ash

Abstract: Bottom ash, as a by-product of coal-fired electric power plants, has recently been used in constructing transportation facilities. However, the use of bottom ash in asphalt mixtures is still in an early stage. The moisture resistance of asphalt mixtures containing bottom ash, which has not been adequately researched, is investigated in this study. Eight asphalt mixtures produced with one type of asphalt cement, two types of aggregate, three sources of bottom ash, and lime additive were evaluated using the principles in AASHTO T283. Analysis of test data indicated that granite mixtures had higher tensile strength values than did limestone mixtures in dry conditions. Addition of lime or bottom ash did not substantially change these values. All mixtures tested met the Superpave volumetric mix design requirement of tensile strength ratio (TSR) after one freeze-thaw cycle. The addition of lime significantly improved the moisture resistance of the asphalt mixtures as measured by the TSR. With lime addition, aggregate type, bottom ash addition, and bottom ash source were all insignificant with respect to TSR. On the basis of TSR rate (TSRR), the addition of lime significantly improved the moisture resistance of the asphalt mixtures subjected to multiple freeze-thaw cycles. Without lime addition, bottom ash played a role similar to that of lime in improving the TSRR for the materials tested.

Reaction mechanism for the CaO-Al and CaO-CaF2 desulfurization of carbon-saturated iron

Abstract: The desulfurization of carbon-saturated iron with CaO is inefficient due to the formation of solid reaction products on the CaO particles which inhibit sulfur transfer. It has been shown in full scale and pilot plant studies that Al improves desulfurization with CaO. The present results indicate that Al affects the rate at 1450 °C, but not at 1350 °C, and that zirconium, which has a stronger affinity for oxygen than Al, does not increase the rate as much as aluminum. Alternate methods of producing a liquid reaction surface, such as desulfurization with CaO-CaF2 or a premelted calcium aluminate flux, also increase the rate. From these results, it is concluded that it is critical to have a liquid reaction surface for effective desulfurization. Aluminum in the metal, reacting with oxygen and CaO, provides a liquid calcium aluminate surface. An optimum aluminum level of about 0.1 to 0.3 pct was found. At lower levels, the Al is consumed and eventually solid calcium silicate forms, and at higher levels, possibly an alumina-rich solid phase forms.

Heavy metal stabilizer

Abstract: The invention discloses a heavy metal stabilizer which comprises sodium bentonite, zeolite powder, sulfydryl-iron base modified charcoal, reduced iron powder and calcium oxide. By carrying out sulfydryl-iron base modification on charcoal, the adsorption property of the heavy metal stabilizer to heavy metal is improved greatly; by mixing the sulfydryl-iron base modified charcoal with sodium bentonite, zeolite powder, reduced iron powder and calcium oxide, the heavy metal stabilizer is obtained. Compared with other materials, the heavy metal stabilizer has a better heavy metal adsorption property, can be applied to soil of different pH and combined pollution of multiple pollutants such as lead, zinc, copper, cadmium and arsenium at different degrees through reasonable proportioning, can simultaneously and effectively reduce exchangeable form quantity of pollutants such as lead, zinc, copper, cadmium and arsenium in soil, and is high in efficiency, stable and effective for a long term.

High thermal emittance coating for X-ray targets

Abstract: A high thermal emittance coating for an X-ray tube anode target comprises a high melting point oxide or a mixture of such oxides added to titanium dioxide and another oxide selected from the group consisting of calcium oxide and yttrium oxide.

Silicone rubber composition for producing cables or profiles with retention of function in the event of fire

Abstract: A composition which is useful for producing profiles and cable insulation which retain their function in the event of fire, comprise peroxidically crosslinking or condensation-crosslinking silicone rubber, metal oxides selected from magnesium oxide, aluminum oxide, tin oxide, calcium oxide and barium oxide and metal compounds of this class which produce oxides on heating, boric acid, zinc borate, and a platinum complex having at least one unsaturated group.