What is particulate matter?
Particulate matteris basically classified into two categories: Particulate matter directly related to materials in and around rigs and Particulate matter in the emissions from the use of diesel fuel. The former is primarily cement dust and fine particles from the handling and storage of sand or another proppant. This type of particulate matter is unlikely to have any impact off the site, and onsite exposure is covered by US Occupational Safety and Health Administration rules.
Fugitive dust emissions in cement factory can be captured by flue gas cleaning devices, generally by electrostatic precipitators (ESP). ESP should remove more than 98 percent of particulates, so, the number of particulate emissions of fugitive dust into the atmosphere will be in a range of 1% to 2% only in most cases.
Due to a constant and continuous increase in industrial globalization and generation of waste, solid waste management has become one of the major global environmental issues that needs to be immediately be dealt with. Cement kiln dust (CKD) is one of such industrial waste or by product that is a progressively significant environmental concern related to its emission and disposal.
Properties of cement kiln dust:
CKD is fine powdery type of material in a shade of grey to tan in colour and is generally formed in a relatively uniform in size. The particle size distribution of CKD depends on the process technology, method of dust collection, chemical composition of CKD, alkali content and various other external factors that can directly and indirectly influence the same. CKD is fine grained, solid, highly alkaline particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the production of cement clinker in the cement industry.
Cement kiln dust that is generated in such a way is partly reused in cement plants and landfills. Due to lack of landfilling space and a constantly increasing disposal cost, the active use of CKD in highway uses, waste treatment, soil stabilization, cement mortar/concrete, CLSM, etc. has become an attractive alternative as compared to its sheer disposal.
Use of cement kiln dust:
Over 2.8 billion tons of cement was generated globally in the year 2009. India has got a huge cement industry as being the second largest cement producer in the world after China with the total capacity of 180 million tonnes, comprising of about 20 cement companies across the country. The generation of CKD has been estimated to be 15–20% of clinker or cement production, which increase the global CKD levels drastically causing for immediate attention to be properly dealt with.
The leachate obtained from cement kiln dust may contain hazardous compounds and its caustic nature poses harmful effects to the environment as well as human health. Hence, it is essential to know the characteristics of leachate obtained from CKD for beneficial utilization towards solid waste management.
Several studies have shown that CKD could be actively used in making cement paste/mortar/concrete within the same industry itself.
Hence the dust produced by the cement industry can be easily utilized within the same industry if proper techniques and measures are used.