Leachable characteristics of arsenical borogypsum wastes and their potential use in cement production.
In this study; the potential use of arsenical borogypsum wastes (ABW) as a set retarder in cement industry was investigated. The comparative performances of arsenical borogypsum wastes (ABW) and natural gypsum samples (NG1 and NG2) at different proportions in the range of 3-8 wt % were tested based on compressive strength over 1, 2, 7, and 28 days and setting times. The use of ABW was observed to lead to a somewhat slower rate of development of strength of the mortar samples than those of NG1 and NG2 during the curing period of 7 days. This is the indication of the effectiveness of ABW as a set retarder. The 28-day compressive strength of mortars tended to decrease with the addition or increasing the proportion of ABW, beyond 5 wt % in particular. The data for setting times of the cement products confirmed set retarding characteristics of ABW with an initial setting time of 90-120 min at 3-5 wt % dosage, which conforms to the desired setting time of > or = 60 min for CEM I (42.5 N) type cement (TS EN 197-1). Leachability tests (TCLP and SPLP) have also shown that ABW can be classified as a nonhazardous waste; but it can readily release metals such as As and Mn, in particular, whereas the mortar samples containing ABW-cement clinker present no environmental concern with its remarkably reduced leachability.
Alp
Ibrahim
I
Department of Mining Engineering, Karadeniz Technical University, 61080 Trabzon, Turkey. ialp@ktu.edu.tr
Deveci
Haci
H
Süngün
Y Halil
YH
Yazici
Ersin Y
EY
Savaş
Mehmet
M
Demirci
Songül
S
D001152:Arsenicals / Q000032:analysis*; D002133:Calcium Sulfate / Q000032:analysis*; D003247:Conservation of Natural Resources; D003252:Construction Materials / Q000032:analysis*; D015386:Hazardous Substances; D055595:Mechanical Phenomena; D008670:Metals / Q000032:analysis; D010316:Particle Size; D013997:Time Factors; D014866:Waste Products / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014961:X-Ray Diffraction
D001152:Arsenicals; D015386:Hazardous Substances; D008670:Metals; D014866:Waste Products; D014874:Water Pollutants, Chemical; D002133:Calcium Sulfate