“…The triboelectrostatic separator consists of two vertical electrode plates and of ejector-tribocharger. The ash particles are charged, injected to an electric field (formed by two plate electrodes) and collected separately depending on their charge (UC is attracted to negative electrode) [157,86,135,136,[149][150][151][152]. However, exposure of the ash to moisture (which is rather common phenomenon) can bring about undesirable behavior and according to Baltrus et al [136] it can be overcome by the addition of Na, Ca or borate ions.…”
“…The triboelectrostatic separator consists of two vertical electrode plates and of ejector-tribocharger. The ash particles are charged, injected to an electric field (formed by two plate electrodes) and collected separately depending on their charge (UC is attracted to negative electrode) [157,86,135,136,[149][150][151][152]. However, exposure of the ash to moisture (which is rather common phenomenon) can bring about undesirable behavior and according to Baltrus et al [136] it can be overcome by the addition of Na, Ca or borate ions.…”
“…The differential charging of different particles in the triboelectrostatic method makes it possible to use a static high voltage separator. Carbon particles are attracted to the negative plate and mineral particles are attracted to the positive plate [12].…”
Beneficiation of fly ash should require for ensuring the removal of reactive elements to reduce the effect of hazardous impact on our atmosphere and can fill the demand for resources such as metals and rare earths. In this chapter, we concentrate to describe the responsible factors involve in fly ash beneficiation that has a great contribution to our environment. The purpose of the current study is to know the recovery of different minerals; maximum removal of the contaminant, reactivity and neutralization capacity of acid mine drainage (AMD) with fly ash and development of the cost-effective method of disposal of fly ash are achieved. Different beneficiation techniques of fly ash and utilization of fly ash are explained.
“…In some cases these problems can be solved by applying physical or chemical pre-treatments or by introducing additives to the mix. Affordable physical treatments are applied quite commonly, for instance by fine grinding [10] or removal of unburnt coal from coal combustion fly ashes [11]. More costly chemical treatments or additives often require additional incentives, such as recovery of other valuable materials (e.g.…”
Section: The Sustainability Challengementioning
confidence: 99%
“…In beneficiation treatments potentially problematic compounds such as free lime, carbon or leachable contaminants are either removed or converted into harmless compounds. For instance removal of (coarse) carbon from coal combustion fly ashes is possible by triboelectrostatic treatments [11], while pre-hydration/washing and carbonation are common ways to reduce free lime, chloride and metal leaching of MSWI bottom ashes [39,40]. Classical magnetic and density separation treatments may be used to separate reactive and non-reactive fractions in complex residues.…”
Section: Unlocking Scms By Beneficiation and Activationmentioning
The partial replacement of Portland clinker by supplementary cementitious materials (SCM) is one of the most popular and effective measures to reduce both costs and CO2 emissions related to cement production. An estimated 800 Mt/y of blast furnace slags, fly ashes and other materials are currently being used as SCM, but still the cement industry accounts for 5-8% of global CO2 emissions. If no further actions are taken, by the year 2050 this share might even rise beyond 25%. There is thus a clear challenge as to how emissions will be kept at bay and sustainability targets set by international commitments and policy documents will be met. Part of the solution will be a further roll-out of blended cements in which SCMs constitute the main part of the binder to which activators such as Portland cement are added. Since supply concerns are being raised for conventional high-quality SCMs it is clear that new materials and beneficiation technologies will need to step in to achieve further progress. This paper presents opportunities and challenges for new SCMs and demonstrates how advances towards more powerful and reliable characterisation techniques help to better understand and exploit SCM reactivity.
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