Browsing by Author "Ercikdi, Bayram"

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Effect of construction and demolition waste on the long-term geo-environmental behaviour of cemented paste backfill
(SPRINGERONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2021) Yilmaz, Tekin; Ercikdi, Bayram; 0000-0003-3288-5192; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Yilmaz, Tekin
The construction and demolition waste (CDW) could be used as backfill material to fill the voids created during the ore production in underground mining. However, there is a need to clarify the impact of CDW on groundwater pollution when it is used as backfill material in cemented paste backfill (CPB) of sulphide-rich tailings (S-rT). This study presents the influence of CDW on the long-term geo-environmental behaviour of CPB samples (CPBs) when used as replacement (10 wt.%) to S-rT. For this reason, the dynamic-tank leaching test was conducted on CPBs and pH, conductivity (Ec), sulphate (SO42-) and heavy metals (HMs) analyses were executed for leachates over 30-360 days of leaching period. The effects of mineralogy and microstructure on the geo-environmental behaviour of CPBs were also analysed via X-ray fluorescence (XRD) and mercury intrusion porosimeter (MIP). The utilisation of CDW in CPB mixtures was found to reduce the SO42- release (up to 13.89%), neutralise the acid generated and lower the Ec (up to 22.16%). Furthermore, the HMs releases (except As, Cu and Zn) were prevented (Ni and Cr) or reduced up to 92%, which is compatible with the improved CPB microstructure. Only the release of arsenic (As) exceeded the limit value for groundwater in CPB of CDW leachate. These findings suggest that not only the cost, strength and stability but also the impact on groundwater pollution should be considered when disposing of CDW as CPB material in underground voids.
Evaluation of geochemical behaviour of flooded cemented paste backfill of sulphide-rich tailings by dynamic-tank leaching test
(TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND, 2020) Yilmaz, Tekin; Ercikdi, Bayram; Deveci, Haci; 0000-0003-3288-5192; 0000-0003-4105-0912; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü
This research elucidates the geochemical behaviour of cemented paste backfill (CPB) of sulphide-rich tailings (S-rT). The dynamic-tank leaching test was performed on the CPBs for up to 360 days. The CPBs with the alkaline industrial by-products (AIPs) produced relatively lower acidity, Ec and SO(4)(2-)than the Control. The AIPs replacement appeared to considerably mitigate the release of heavy metals (HMs) including As. Only Mo and As in CPBs of AIPs exceeded the limit-values for ground-water. These findings demonstrated that a suitable CPB mixture design to control the release of all HMs in CPB is of practical importance for ground-water quality.
Evaluation of the neutralization performances of the industrial waste products (IWPs) in sulphide-rich environment of cemented paste backfill
(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND, 2020) Yilmaz, Tekin; Ercikdi, Bayram; Cihangir, Ferdi; 0000-0003-3288-5192; 0000-0003-3945-1055; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü
The purpose of this research is to examine the neutralization performances of CaO-rich industrial waste products (IWPs) in the sulphide-rich environment of cemented paste backfill (CPB). A total of 205 CPB samples were prepared by using four different IWPs (type-C fly ash (C-FA), blast furnace slag (BFS), calcitic limestone (CL) and dolomitic limestone (DL)) as 5, 10 and 15 wt% substitute for sulphide-rich tailings. These CPB samples were cured and subjected to the acid (pH) and sulphate (SO42-) tests during 7-360 days of curing periods. MIP and XRD tests were also carried out to understand the generation of acid and sulphate and their effect on CPB stability at 28 and 180 days. The findings indicated that the utilisation of IWPs in CPB mixtures mitigated the acid (up to 58.9% higher pH values) and sulphate (up to 72.1% lower SO42- ion release) production, and enhanced the microstructure (12.43% lower total porosity) of CPBs owing to the neutralization potential, pore-filling effect, pozzolanic and partially binding characteristics of IWPs. It can be inferred from these findings that the IWPs can be suitably utilised as neutralization materials in CPB of sulphide-rich tailings. This in turn allows the mitigation of potential disposal/pollution problems associated with these IWPs.