Papers by Keyword: Lime Sludge

Abstract: Lime sludge (LS) is a solid waste from lime making industry and normally disposed in landfill or recycled. LS has been studied as one of the raw materials in various ceramic productions such as bricks, ceramic tiles and glass-ceramics. In this study, LS was utilized in the preparation of bioactive glass using the 45S5 bioactive glass. The 45S5 bioactive glass contains SiO₂ (45 wt.%), Na₂O (24.5 wt.%), CaO (24.5 wt.%) and P₂O₅ (6 wt.%). It has the ability to bond with soft tissue and promote bone growth. The LS was combined with bioactive glass as a potential replacement of calcium carbonate (CaCO₃). The ratio between LS:CaO was varied (0:100, 25:75, 50:50, 75:25 and 100:0) to study the effect of LS weight percentage on the bioctive glass. The preparations of bioactive glasses involved batching, mixing, melting at 1400 °C, water quench and milling. LS was characterized using X-ray diffraction (XRD), while the fabricated glasses were characterized using particle size analyzer, XRD and scanning electron microscopy (SEM). The XRD results proved that the phase and chemical composition of bioactive glass were not affected by the addition of LS. The XRD and SEM results indicated that the addition of lime sludge in bioactive glass was effective to promote the formation of hydroxyapatite (HA) layer.

Abstract: An impoundment is an engineering construction used for the safe deposition of unexploitable waste from industrial and mining facilities. In terms of the legislative requirements of the Slovak Republic, a Measurements Project must be developed for each impoundment. In this document the prerequisites for the safe operation of an impoundment, the limit and critical values of the monitored phenomena and the facts influencing the safety of the impoundment and the area endangered by such a site are also defined. The safety and stability of an impoundment are verified according to a Measurements Project by considering stability at regular time intervals. This contribution presents, in the form of a parametric study, a stability analysis of a lime sludge impoundment. The stability analysis provides an example of the utilization of an information database of the results of the regular monitoring of the geotechnical properties of the materials forming the impoundment ́s body and the surrounding rock mass.

Abstract: This paper shows that a new approach (i.e. cold-bonding technique) to recycle uncontaminated and innocuous lime sludge as coarse aggregates. The cold-bonding technique incorporates the principles of the cement chemistry and composite material to develop recycling coarse aggregates. Herein lime sludge was regarded as the main materials to produce recycling coarse aggregates, which meet the specifications of green building materials in Taiwan, using the cold-bonding technique instead of sintering method in light of the issues of reduction of waste, energy, and CO₂ footprint. The results show that the specific gravity (in the oven-dry state, OD) of recycling coarse aggregate is in the range of 1.20 to 1.23; the absorption capacity is in 40.0 to 44.6 %; the dry loose density (i.e. unit weight) is 811 to 837 kg/m³; the single particle compressive strength at 28-day is in the range of 17.8 to 20.4 MPa; the particle cylindrical crushing strength ranges from 27.9 to 33.8 MPa; other characteristics also satisfies ASTM C33. The developed recycling coarse aggregates could increase the reuse and recycling of lime sludge, reduce the energy consumption and CO₂ footprint, and diminish the impact on the environment and future generations.

Abstract: Utilization of industrial and agricultural waste products in the construction industry has been the focus of research for economical and environmental reasons. In this paper, Lime sludge, a paper and pulp industry waste product, has been chemically, physically and thermally characterized, in order to evaluate the possibility of its use as construction materials. X-ray Fluorescence and X-ray diffractometry studies for the determination of composition and presence of crystalline material and Thermo Gravimetric Analysis to identify the phase transition of lime sludge, as well as physical and mechanical properties and its pozzolanic activity have been conducted. It is concluded that the acceptance of this waste product by the construction industry could be decided depending on the application, keeping in view of the limitations on the mechanical strength.