الفهرس 
Studies on granulated blast furnace slag (GGBFSOnly 14 pages are availabe for public view
 |  | from | 266 |  |  |
| | | from | 266 | | |
Abstract
The environmental pollution by various wastes has been concerned in the world and these pollutants become hazardous for human health, animals and ecological environment as they accumulate for a long period. Get ridding of these wastes by land-filling or dumping has a negative impact on the surrounding environment and have high cost in transportation .So there are many efforts carried out by using the solidification / stabilization (S / S) method inside a solid matrix to minimize escaping of heavy metals via leaching. blast furnace slag and fly ash are the most popular solidification agents for inorganic wastes. Therefore, the aim of this study is to investigate the immobilization of some heavy metal salts by using alkali activated ground granulated blast furnace slag (GGBFS) paste and mixture of GGBFS/FA pastes as well as the hydration characteristics measurements.
This study investigated the influence of addition of different Pb2+ sources (lead acetate – lead bearing sludge) in different concentration 0.5,1and 2wt% and activator type (NaOH, NaOH/Na2SiO3) on the performance and physico-mechanical properties of alkali activated slag and mixture of GGBFS/FA . Also this study investigated the influence of addition of different concentration of heavy metal rich sludge (HMRS) 2.5, 5,7.5, 10 wt% contains mixture of heavy metals (Ni2+, Mn2+, Cu2+, Cr2+) and activator type (NaOH, NaOH/Na2SiO3) on the performance and physico-mechanical properties of alkali activated slag and mixture of Slag/Fly Ash, 60/40. In addition, the immobilization of Pb2+ and other heavy metal ions was investigated.
.
Each GP and cement pastes were prepared by mixing with the suitable amount of water. The water to solid ratio was 0.24 for all mixes except for the mixes containing HMRS ; the W/S ratio was 0.28. All blended mixes were first manually mixed in the dry state to attain complete homogeneity. 0.5, 1 , 2 wt % of Pb2+ ion in metal salt, with respect to the weight of the mix dissolved in part of volume of water, the sodium hydroxide and sodium silicate were dissolved in the remaining volume of water of geopolymer mixing . 0.5, 1, 2 wt % of Pb2+ in LBS and 2.5 , 5 ,7.5 and 10 wt% of HMRS are used . The samples were preparing by the same way for 100% GGBFS and (GGBFS/FA,60/40%) using NaOH and (NaOH/Na2SiO3,1:1) .The mixing was carried out on a smooth and non – absorbent surface with the aid of an ordinary gauging towel. The operation was completed by continuous and vigorous mixing for about three minutes. After complete mixing the resulted pastes were molded into cubic specimens by using one - inch cube moulds. Compacting by vibration was carried out; the leveling and smoothness of the top surface of the pastes were done by a thin edged towel. The moulds containing the pastes were then cured at room temperature for the first 24 hours in order to attain the final setting of the specimens. The hardened pastes were then removed from the moulds and cured at ~ 100 % RH atmosphere up to 28 days. After 28 days from hydration, the samples used for the leaching measurements.
The effect of addition of lead content (Lead acetate or lead bearing sludge) and heavy metals rich sludge on hydration characteristics of alkali activated GGBFS or GGBFS/FA (60:40%) was investigated. In addition, the immobilization of Pb2+, Cr3+, Mn2+, Ni2+ and Zn2+ was evaluated.
This was carried out via the following tests:
1. Determination of the compressive strength.
2. Determination of the chemically combined water content.
3. Determination of total porosity.
4. X-ray diffraction (XRD) analysis.
5. Scanning electron microscope (SEM) examination.
6Leaching measurement.