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.

Compound high-efficiency desulfurizer

Abstract: The invention discloses a compound high-efficiency desulfurizer The compound high-efficiency desulfurizer is prepared from the following raw materials in part by weight: 10 to 20 parts of magnesium oxide, 15 to 20 parts of calcium oxide, 15 to 20 parts of calcium carbide, 12 to 18 parts of barium carbonate, 8 to 15 parts of sodium carbonate, 7 to 12 parts of zinc oxide, 7 to 12 parts of magnesium powder, 3 to 8 parts of sodium chloride, 3 to 10 parts of ferrous sulfate, 4 to 10 parts of silicon dioxide, 3 to 10 parts of magnesium chloride and 8 to 13 parts of calcium fluoride A method for preparing the compound high-efficiency desulfurizer comprises the following steps of: drying and crushing the raw materials respectively to ensure that the particle size of each component is 03 to 08mm, mixing the components in a proportion, and fully stirring to obtain a finished product In this way, the compound high-efficiency desulfurizer is applicable to the desulfurization treatment of various materials, and the manufacturing process is simple and reasonable, has a good desulfurization effect and is low in production cost

Characterisation and performance of three promising heterogeneous catalysts in transesterification of palm oil

Abstract: In this work, the performance of three heterogeneous catalysts, namely potassium hydroxide/γ-alumina, bulk calcium oxide, and nano-calcium oxide, in comparison with the homogeneous potassium hydroxide was studied in the transesterification of palm oil to produce methyl esters and glycerol. The physical and chemical properties of the heterogeneous catalysts were thoroughly characterised and determined using a number of analytical methods to assess their catalytic activities prior to transesterification. The reaction products were analysed using liquid chromatography and their properties were quantified based on the American Society of Testing and Materials and United State Pharmacopoeia standard methods. At the 65°C reaction temperature, the oil-to-methanol mole ratio of 1: 15, 2.5 h of the reaction time, and catalyst (φ r = 1: 40), potassium hydroxide, potassium hydroxide/γ-alumina, nano-calcium oxide, and bulk calcium oxide gave methyl ester yields of 97 %, 96 %, 94 %, and 90 %, respectively. The impregnation of γ-alumina with potassium hydroxide displayed a catalytic performance comparable with the performance of potassium hydroxide where the former could be physically separated via filtration resulting in a relatively greater purity of products. Other advantages included the longer reusability of the catalyst and more active sites with lower by-product formation.

A consecutive decomposition–sintering dilatometer method to study the effect of limestone impurities on lime microstructure and its water reactivity

Abstract: In this paper we develop a consecutive decomposition–sintering dilatometer method (CDSD) to study the effect of limestone impurities on lime microstructure features that are formed during the limestone decomposition. Two experimental parameters, the changing in slope of the dilatometer traces ( β ˙ ) and the total shrinkage of the produced lime (Σ) in the subsequent sintering stage, have been shown to be influenced by the impurities. The first limestone investigated was poorly recrystallized with heteroblastic texture and a total amount of impurities equal to 2.2 wt%. The second limestone was strongly recrystallized limestone with equigranular xenotopic fabric and with 0.7 wt% total impurities. β ˙ and Σ turns-out to be 13 × 10−4 [min−1] and 1.43 wt% for the lime from the first sample, and 3 × 10−4 [min−1] and 11.2 wt% for the calcium oxide from the second one. Sintering steps among CaO grains catalysed by the escaping CO2 lead, in the first lime–limestone matrix, to lime grains of irregular shapes and average dimensions between 3 and 7 μm. In the second lime–limestone matrix, liquid phases between CaO and impurities promote locally denser oxides regions mixed with others where solid-state sintering steps occurs. In these regions the average grain dimensions are 6–10 μm. CDSD methods allow to understand the lime water-reactivity vs. the temperature of lime formation tests in term of competition between coarsening and densification phenomena occurring in the temperature range 700–1200 °C and in air.