Development of a novel non-contact and quick-response detector for boron in coal fly ash based on thermal neutron absorptiometry

Hiroyuki Masaki,Shinji Yasuike,Kenji Matsumoto,Masaru Tajiri,Yoshihiro Yoshioka,Seiji Inoba

doi:10.1016/j.heliyon.2018.e00752

Abstract

Coal fly ash (CFA), a by-product from coal-fired power plants, has many applications. However, there are concerns that the trace elements in CFA-based materials may contaminate groundwater. Therefore, many methods have been developed to rapidly measure these trace elements in CFA in order to management and/or screening their leachability. However, satisfactory methods to measure boron alone have not been reported. In this study, we developed an instrument for the non-contact analysis of boron in CFA samples. This simple instrument consisted of a sealed neutron source, a moderator, a proportional counter, and a signal processing device. The analysis method, based on thermal neutron absorptiometry, can rapidly measure the boron content within five minutes without pre-treatment. We applied the developed equipment to over 200 CFA samples, and excellent correlation was obtained between the proposed and traditional methods. These results indicated that the developed equipment is useful for managing and/or screening boron in CFA.

Highlights

Coal fly ash (CFA) is a by-product from coal-fired power plants
Trace elements in CFA are determined with atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma optical emission spectrometry (ICP-OES) [12, 13, 14, 15]
Chromium, arsenic, selenium, lead, and other metals are measured by X-ray fluorescence (XRF) [16, 17, 18], mercury is measured by pyrolysis AAS [19], and fluorine is measured by combustion ion chromatograph [20, 21]

Summary

Introduction

Coal fly ash (CFA) is a by-product from coal-fired power plants. The global generation of CFA is as much as over 750 million tons per year [1]. Despite the great potential of CFA-based materials in geotechnical applications, there are environmental concerns about the hazardous trace elements in CFA, such as boron, fluorine, chromium, arsenic, selenium, mercury, and lead [5, 6]. Chromium, arsenic, selenium, lead, and other metals are measured by X-ray fluorescence (XRF) [16, 17, 18], mercury is measured by pyrolysis AAS [19], and fluorine is measured by combustion ion chromatograph [20, 21] Such simple and rapid analysis methods of boron in CFA without acid digestion have not been reported

Methods

Results

Conclusion