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.

Cementitious materials including slag and geopolymers

Abstract: Cementitious materials including slag and geopolymer can be added to conventional cement compositions, such as Portland cement, as a partial or total replacement for conventional cement materials. The slag may comprise silicates and/or oxides of calcium, silicon, magnesium, iron, aluminum, manganese, titanium, sulfur, chromium and/or nickel. The geopolymer may comprise aluminum silicate and/or magnesium silicate. In a preferred embodiment, curing of concrete materials by the action of water on the cementitious materials is enhanced with the addition of an activator component selected from calcium bromide, calcium nitrate, calcium nitrite, calcium chloride, calcium oxide, and sodium bromide.

Method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar

Abstract: The invention discloses a method for recovering polysilicon ingots, carborundum powder and polyethylene glycol from cutting waste mortar The recovering method comprises the following steps shown as an attached diagram, wherein the high temperature purification comprises the following steps of: mixing the prepared silicon micro powder with a fluxing agent according to the weight ratio of 1: 05-5 into lumps, carrying out high temperature treatment in a high temperature vacuum furnace with the treatment temperature range of 1450-1800 DEG C and the treatment time range of 1-10h; and then carrying out directional solidification on melting-state high purity silicon subjected to the high temperature treatment to obtain the polysilicon ingots; wherein the fluxing agent is selected from one or any mixture of silica, alumina, calcium oxide, magnesium oxide, potassium oxide, sodium oxide, calcium fluoride, magnesium fluoride, sodium fluoride, sodium chloride, potassium chloride and calcium chloride The invention has the advantages that: the yields of carborundum and polyethylene glycol are high and can reach more than 70-80 percent; and the recovered polysilicon ingots reach the purity of 6-7N and completely satisfy of the requirement for preparing silicon slices of silicon solar cell

Vitrifiable mixture for quality glasses

Abstract: The glass has a chemical composition as a percentage by weight within the following range: silica 50-58, potash 0-13, soda 0-9, lithium oxide 0-4, calcium oxide 0-3, magnesium oxide 0-4, boric anhydride 0-2, zinc oxide 16-30, barium oxide 0-12, titanium oxide 0-6, zirconium oxide 0-5, yttrium oxide 0-5, alumina 0-3, tin oxide 0-5, lanthanum oxide 0-9, niobium oxide 0-9, bismuth oxide 0-12, germanium oxide 0-5.

Low-boron glass fibers and glass compositions for making the same

Abstract: Low-boron, high-barium glass compositions and fine-diameter glass fibers for forming clean room HEPA and ULPA filters, are provided. The compositions and resulting glass fibers preferably comprise a low concentration, less than about 1 weight percent, of boric oxide, a relatively high concentration of barium, such as from about 5.5 to about 18 weight percent barium oxide, and a concentration of alkali oxide ranging from about 10 to about 14.5 weight percent. Alumina is preferably present in the glass fiber compositions and the resulting glass fibers in a range of from about 4 weight percent to about 8 weight percent, and calcium oxide and magnesium oxide are preferably present in a range of from about 1 weight percent to about 6 weight percent and from about 0 weight percent to about 3.5 weight percent, respectively. The glass fiber compositions also preferably include from about 2 to about 6 weight percent zinc oxide, from about 0.1 to about 1.5 weight percent fluorine, and very low concentrations of manganese oxide, ferric oxide and various impurities such as strontium oxide, lithium oxide, titanium oxide, and zirconium oxide. Preferably, the balance of the composition is silicon dioxide.

Thermal behavior of calcite as an expansive agent

Abstract: In this paper, thermal behavior of calcite as raw material of CaO-based expansive agent was investigated. The products were characterized by using differential thermal analysis (DTA), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD). DTA curves show that calcite has endothermic peak and impurity affects the onset of reactions. The more the impurity increases, the more energy changes increase. At 800-900°C, calcite was decomposed into solid calcium oxide (CaO) and gaseous CO2. Lime (CaO) used as the base of expandable material is the ultimate product of heated calcite. The calcium oxide phase, in reaction to water forms portlandite, at an onset temperature of about 900°C was also characterized by the appearance of the FT-IR mode at 867,3424 and 3644 cm-1. XRD results show that quartz impurity in calcite samples at 900°C forms larnite phase (Ca2SiO4). The expansions are mainly generated from the hydrations of CaO in the CaO-type expansive agent.