CHLORINATION AND ACTIVATION OF PENNSYLVANIA ANTHRACITES
Special Research Report SR-59 The object of this work was to produce an active carbon from Pennsylvania anthracite with low ash content. Commercially available Pennsylvania anthracites at present, contain at least 6 per cent mineral matter, which following normal activation will be increased to at least 12 per cent. This high ash content is unacceptable in most applications. Kinetic studies on mineral matter removal by high temperature chlorination of various Pennsylvania anthracites and sink-float fractions were conducted in the temperature range from 1000°-1200°C. It was found that a large fraction of the discrete mineral matter was removed in the first hour of chlorination. An electron microprobe was used to examine the mineral matter distribution in anthracite with reference to Si, Al, and K. The effect of chlorine on the removal of these constituents at 900°C was also studied. It was established that chlorine removed mineral matter along its periphery and that chlorine is strongly chemisorbed in the carbon phase. High ash refuse anthracite was chlorinated with and without carbon monoxide. It was observed that (1) carbon is the active reducing agent in the chlorination of refractory oxides in anthracite, and (2) carbon- mineral matter contact determines the extent by which the amount of mineral matter is removed. Prechlorinated and devolatilized anthracite was activated in carbon dioxide and steam in a fluidized bed at 950°C. The following runs were performed: (1) activation with carbon dioxide followed by chlorination, (2) activation with a mixture of carbon dioxide and chlorine, (3) activation of prechlorinated samples in carbon dioxide, and (4) activation of prechlorinated samples in steam. Activation of prechlorinated anthracite was demonstrated to be the superior process for produci.ng activated carbon of those studied. Prechlorination resulted in (1) an increased gasification rate of anthracite in carbon dioxide or steam, and (2) an active carbon of significantly larger surface area and lower ash content. In some cases, active carbons having ash contents of only 3.5-5.0 per cent were produced. These materials are thought to be of commercial interest. Steam activation removed most of the chemisorbed chlorine.
|CHLORINATION AND ACTIVATION OF PENNSYLVANIA ANTHRACITES
|Attribution-NonCommercial-NoDerivs 3.0 United States
|July 27, 2016
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