ElBaz et al., J. Mater. Environ. Sci., 2019, 10(11), pp. 1062-1073 1062 J. Mater. Environ. Sci., 2019, Volume 10, Issue 11, Page 1062-1073 http://www.jmaterenvironsci.com Journal of Materials and Environmental Sciences ISSN : 2028-2508 CODEN : JMESCN Copyright © 2019, University of Mohammed Premier Oujda Morocco Review of beneficial uses of cement kiln dust (CKD), fly ash (FA) and their mixture A. A. Elbaz 1 , A. M. Aboulfotoh 1* , A. M. Dohdoh 1 , A.M. Wahba 1 1 Environmental Engineering Department, Faculty of Engineering, Zagazig University, Zagazig, Sharkia, 44519, Egypt. 1. Introduction 1.1 Cement kiln dust Cement kiln dust (CKD) is an industrial by-product formed during the manufacture of cement and is a waste material that is traditionally destined for landfills. It is a fine powdery material similar in appearance to Portland cement [1]. Wet-process kilns and dry-process kilns are the main two types of cement kiln processes, the first type accept feed materials in a slurry form; and the later one accepts feed materials in a dry ground form. The exhaust gases from cement production process are passed through dust collection system (e.g., cyclone). Part of the collected CDK from the cyclone could be returned to the kiln. The production of one ton of cement generates around 0.06-0.07 ton of CKD. Global cement production is expected to increase from 3.27 billion metric tons in 2010 to 4.83 billion metric tons in 2030; with approximately 220 million tons of cement dust is discarded annually from these cement manufacturing facilities. X-ray diffraction analysis of cement kiln dust showed that the main constituent is calcite (CaCO3), quartz (SiO2) and calcium sulfate (CaSO4) [2]. CKD is generally non-hazardous because of its relatively low leaching properties for heavy metals. However, its presence in open atmosphere for a long period may have significant effects on the environment. Trace constituents include cadmium; lead, selenium, and radionuclide are generally found at concentrations of less than 0.05 percent by weight in CKD. However, since these constituents are potentially toxic, and its concentrations can vary between cement plants, it is important to assess the mobility and leach ability of these traces constituents in the CKD [3]. 1.1.1 Environmental problems related to CKD: Dust emissions originate mainly from the raw mills, the kiln system, the clinker cooler, and the cement mills. A general feature of these process steps is that hot exhaust gas or exhaust air is passing through pulverised material resulting in an intimately dispersed mixture of gas and particulates. The nature of the particulates generated is linked to the source material itself, that is, raw materials (partly calcined), clinker or cement. These emissions are not only deteriorating air quality but also degrading human health. Emissions have local and global environment impact resulting in global warming, ozone depletion, acid rain, biodiversity loss, reduced crop productivity etc. [4] Abstract Beneficial use of industrial by product materials has the potential to provide economic benefits such as preserve raw resources, and avoid negative environmental impacts associated with the acquisition and processing of raw materials. Cement kiln dust (CKD) and Fly Ash (FA) are by-products formed during the manufacture of cement and coal-fired electricity generation respectively. The present work presents a general review on the applications of the CKD and FA in the field of agriculture, waste treatment, soil stabilization, concrete and cement industry. These beneficial uses of CKD and FA can contribute significant environmental and economic benefits. Environmental benefits can include reduced greenhouse gas emissions, reduced need for disposing in landfills, and reduced use of virgin resources. Economic benefits can include job creation in the beneficial use industry, reduced costs associated with CKD and FA disposal, increased revenue from the sale of CKD and FA, and savings from replacement of other more costly materials. Received 17 Aug 2019, Revised 03 Oct 2019, Accepted 04 Oct 2019 Keywords Agriculture, By products reuse, Cement Kiln Dust Fly Ash, Soil stabilization, Waste management, [email protected]; [email protected] Phone: +201111784499; Fax: +20552304987
Review of beneficial uses of cement kiln dust (CKD), fly ash (FA) and their mixture
May 03, 2023
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