Kiln Waste Research Articles

Efficient in-situ conversion of low-concentration carbon dioxide in exhaust gas using silver nanoparticles in N-heterocyclic carbene polymer

Efficient utilizing CO2 is crucial approaches in achieving carbon neutralization. One of the challenges lies in the in-situ conversion of low concentration CO2 found in waste gases. This study introduces a novel heterogeneous catalyst known as silver nanoparticles in porous N-heterocyclic carbene polymer (Ag@POP-NL-3). The catalyst is synthesized via a streamlined pre-coordination method. Ag@POP-NL-3 exhibits uniform distribution of silver nanoparticles, a porous structure and nitrogen activation groups. It demonstrates high efficiency and selectivity in absorbing and activating CO2 and enabling the conversion of low concentration CO2 (30 vol%) from lime kiln waste gas into cyclic carbonate under mild conditions. This catalytic system achieves both CO2 capture and resource utilization of CO2 simultaneously, effectively fixing low-concentration CO2 from waste gases into C2+ valuable chemicals. This approach elegantly addresses two goals in one solution.

Effect of Fine Aggregates and Mineral Fillers on the Permanent Deformation of Hot Mix Asphalt

Conventional asphalt pavement is the dominant mode of passenger and freight traffic in Pakistan. As a result, asphalt pavements suffer from various failures, where rutting, corrugation, and fatigue cracking are significant. Fine aggregates and mineral fillers play a pivotal role in providing structural integrity in asphalt pavements when subjected to traffic and the environment. The current study aims to examine the effects of various locally accessible fine aggregate and mineral filler materials on the interlocking properties of asphalt mixtures in relation to internal friction angle, rutting resistance, and controlling environmental pollution as an indirect benefit, thereby reducing wastes. Four distinct asphalt samples were prepared using cinders, stone dust, natural sand, and surkhi as fine aggregates and mineral fillers, as a full replacement, as per ASTM D1559, confirming the Asphalt Institute’s gradation for asphalt wearing course. Optimum binder contents (OBC) of 4.40%, 4.1%, 6.57%, and 6.63% by weight of Marshall specimen were concluded for asphalt samples containing stone dust, natural sand, cinder, and surkhi, respectively. The results revealed that surkhi, natural sand, stone dust, and cinder all showed a diminishing tendency in developing interlocking properties in asphalt mixtures at internal friction angles of 35°, 33.7°, 32°, and 28.4°, respectively. The wheel tracking test results revealed that the asphalt samples made with surkhi as fine aggregates and fillers have the highest rut resistance, whereas samples made with cinders as fine aggregates and fillers have the lowest rut resistance. The direct shear test showed that fine aggregates with a larger angle of internal friction are significantly more stable in terms of rut resistance than fine aggregates with a smaller angle of internal friction. The current research will help to prevent pavement rutting and corrugation by adding surkhi into asphalt pavements, with the reduction in brick kiln waste providing an indirect benefit.

Porcelain waste and porcelain production in Worcester: the landscape evidence from fieldwalking

Summary Field survey can provide a longitudinal sample of ceramic production from the porcelain factories which operated in the city of Worcester from 1751 to 2009. Until the twentieth century domestic and industrial waste from the city was used as manure/hard core on fields throughout the county. We have found kiln waste and biscuit wasters from the earliest phases of production to wares made in the late 19th/twentieth century, along with contemporaneous domestic discard. This assemblage provides a series of snapshots of porcelain and semi-porcelain production allowing us to identify trends in types of fabrics, forms, manufacturing and consumption.

Direct Conversion of CO2 in Lime Kiln Waste Gas Catalyzed by a Copper-Based N-heterocyclic Carbene Porous Polymer.

Industrial waste gas is one of the major sources of atmospheric CO2 , yet the direct conversion of the low concentrations of CO2 in waste gases into high value-added chemicals have been a great challenge. Herein, a copper-based N-heterocyclic carbene porous polymer catalyst (Cu@NHC-1) for the direct conversion of low concentration CO2 into oxazolidinones was successfully fabricated via a facile copolymerization process followed by the complexation with Cu(OAc)2 . A continuous flow device was designed to deliver a continuous and stable carbon source for the reaction. Due to the triple synergistic effect of its porous structure, nitrogen activation sites and catalytic Cu center, Cu@NHC-1 shows highly efficient and selective adsorption, activation, and conversion of the low concentration CO2 (30 vol%). Its practical application potential is demonstrated by the ability to successfully convert the CO2 in lime kiln waste gas into oxazolidinones in satisfactory yields under mild conditions.

Multi-objective optimization and off-design performance based on thermodynamic -economic-environmental analysis of organic Rankine & Kalina cycles for roller kiln waste heat recovery

ABSTRACT Heat recovery from roller kiln’s flue gas and cooling gas is interest topic to make ceramic tile production cleaner and more sustainable. Comparatively, the parallel double-evaporator regenerative organic Rankine cycle (PD-RORC) & Kalina cycle (PD-KC34 (Kalina cycle 34)) provide a good solution for a roller kiln’s low-temperature double heat sources utilization. In this research, the off-design performance of the multiobjective optimized PD-RORC & PD-KC34 based on thermodynamic-economic-environmental model is investigated to provide dependable assessment for the roller kiln’s waste heat recovery. Firstly, the multiobjective optimization of PD-RORC & PD-KC34 is carried out considering thermodynamic, economic and environmental factors, and TOPSIS method is used to select the optimal Pareto solution. Then, the influences of the roller kiln’s operating conditions and heat sink on the off-design performances of PD-RORC & PD-KC34 are further explored. The results show that, under the optimal condition, PD-RORC has superior exergy efficiency () and environmental performance with of 49.76% and environment impact load () of 0.096 mPEChina,90/kWh while PD-KC34 has better net power output () and economic behavior with of 250.72 kW and electricity production cost () of 0.090 $/kWh. In addition, excess air coefficient has the greatest impact on , , and for PD-RORC and PD-KC34. On the whole, PD-KC34 has higher sensitivity on and while PD-RORC shows greater sensitivity on and .

Rejected pottery in Gebel Barkal: Revisiting the localisation of ceramic workshops in the Kingdom of Meroe (Sudan)

The article analyzes the results of a study of the modern day surface of the ceramic accumulation (“pottery dump”) in Gebel Barkal, carried out by the author as a member of the Russian-Sudanese Archaeological Mission at Gebel Barkal (IOS RAS – National Corporation for Antiquities and Museums (NCAM, Sudan)). During the survey of the territory north of the Great Temple of Amun, 239 samples of rejected pottery were found and a map of their location was compiled. The highest concentration of objects is confined to the north-western part of the “pottery dump”, while moving south and east, the number of samples noticeably decreases. All the samples belong to the small moulds for baking bread with plain rim, conical body and pointed bottom. Some of them had simple potmarks. Among the samples, all possible variants of kiln waste are presented – deformation, cracking, melting and sintering of vessels. According to the accompanying ceramic material – fragments of a Hellenized krater with geometric painting, rejected pottery can be dated to the 3rd–1st centuries B.C. The dominance of bread moulds indicates their connection with temple bakeries of the Great Temple of Amun that were nearby, but not yet discovered. The size of the “pottery dump” in Gebel Barkal, covering the area of more than 9500 square meters, indicates a significant amount of consumption of bread by temple staff and pilgrims. The presence of rejected pottery clearly indicates the connection of the “pottery dump” with ceramic workshops, presumably located in its northern part, between the Barkal Mountain and building B 2300.

Influence of electric arc furnace dust and lime kiln waste in Portland cement hydration

Abstract Studies have indicated that the use of electric arc furnace dust (EAFD) results in a delay in the hydration time of Portland cement. Calcium-rich waste such as lime kiln waste (LKW) is one of the techniques used to offset this delay as it accounts for the lack of this element in calcium silicate hydrate (C-S-H) production in the mixture. The objective of this study was to evaluate the influence of electric arc furnace dust (EAFD) and lime kiln waste (LKW) in the hydration process of Portland cement pastes and their influence in setting time and hydration heat. The methodology used required several steps: physiochemical and micro-structural characterization of waste samples; definition and production cement pastes with different levels of waste substitution and a reference paste and evaluation of the cement pastes with respect to setting time and hydration heat. Results showed that the substitution of 1% EAFD with or without LKW presented similar hydration heats as the reference paste. This indicated that EAFD+LKW substitution would not affect substantially the hydration reactions of cement and could allow waste recycling in construction materials.

Utilization of cement rotary kiln waste heat for calcination of phosphogypsum

The cement industry nowadays is giving thrust to replace and reduce fossil fuel-based energy through recovery of waste heat, utilization of wastes (Alternative fuels) and adoption of renewable energy sources like wind energy, solar PV systems etc.In cement plants, high temperature heat is released into the atmosphere through exhaust flue gases, radiation and convection heat from hot and exposed surfaces like rotary kiln. A lot has already been explored about recovery of waste heat from exhaust hot flue gases. Many Indian cement plants have installed Waste Heat Recovery Systems (WHRS) at their facility for generating electricity by using heat energy in hot flue gases. At present cumulative generation capacity is estimated as ~344 MW from such WHRS facilities in Indian cement plants.Indian cement industry is facing issues about limited availability of the mineral gypsum. This is going to be more critical with possible restrictions over mineral gypsum import in India. On the other hand, the huge inventory of phosphogypsum is a challenge for phosphoric acid manufacturing plants. Phosphogypsum can’t be used without processing in the cement production process due to adverse impact on cement properties. Processing of Phosphogypsum requires high temperature and if the temperature is raised through fossil fuel combustion then it will add to extra cost and associated Green House Gas (GHG) emissions. Heat recovery from kiln hot shell surfaces can be explored for phosphogypsum calcination purpose here. A feasibility concept of phosphogypsum calcination through kiln waste heat recovery is discussed in this paper.

Environmentally sound destruction of hexachlorobutadiene during waste incineration in commercial- and pilot-scale rotary kilns

Hexachlorobutadiene (HCBD) is a persistent organic pollutant (POP) that is banned in many countries. To investigate the destruction of HCBD in industrial waste, we conducted incineration tests at a commercial-scale incineration plant equipped with a 130-t/day rotary kiln and at a pilot-scale plant with approximately 2-kg/h of feeding rate. At the commercial-scale plant, waste oil containing 37% by weight of HCBD was co-incinerated at 1058 °C together with the solid and liquid industrial wastes that the plant normally processes. The concentrations of HCBD in the bottom ash (0.25 ng/g-dry), effluent slurry (2.8 ng/L), and stack gas (8.2 ng/m3N) were comparable with those obtained when only the usual industrial waste was incinerated. A destruction efficiency of 99.999996% was obtained from the co-incineration test, with negligible discharge of chlorinated dioxins and furans. At the pilot-scale plant, refuse-derived fuel spiked with HCBD was incinerated. It was found that both decomposition and unintentional generation of HCBD occurred simultaneously in the primary combustion chamber; however, the decomposition rate exceeded the generation rate to afford a destruction efficiency of 99.99993%. Together, these results indicate that HCBD contained in industrial waste can be efficiently destroyed in best available technology (BAT) rotary kiln waste incinerators.

Recycling Of The Mixture Resulted From Sanitary Ware Waste, Roller Kiln Waste And Ceramic Tiles Sludge Waste In The Manufacturing Of Ceramic Floor Tiles

Ceramic tiles industry is a big source for wastes that have a bad effect on the environment. The first source of waste is associated with roller kilns as it needs a periodic surface grinding to its rollers which results in a waste powder. The second type of waste is ceramic tiles sludge which produced from a water treatment plant. The third waste is sanitary ware waste which coming out from sanitary ware industry. The main aim of this paper is to investigate the ability of substituting part of the main body mixture of floor tiles by these three types of waste powder. Many Experiments were done on the raw materials. Rectangular tile specimens were moulded, dried and fired. Sintering parameters and mechanical properties were determined. The sample that consist of 2% Roller Kiln, 39% Ceramic tiles sludge, 15% sanitary ware waste, and 44% Floor tiles mixture has the optimum properties.

Recycling of the Mixture Resulted from Roller Kiln Waste and Ceramic Tiles Sludge Waste in the Manufacturing of Ceramic Floor Tiles

Ceramic tiles industry produced many types of wastes that are routinely discarded as stock piles. One of the environmental problems associated with roller kilns is the periodic need to grind its rollers which results in a waste powder. The second type of waste is ceramic tiles sludge which produced from a water treatment plant in the ceramic tiles factory. This paper investigates the probability of substituting part of the main body of floor tiles mixture by these two types of waste powder. Many Experiments were done on the raw materials. Rectangular tile specimens were molded, dried and fired. Linear firing shrinkage, loss on ignition, sintering parameters, and mechanical properties were determined. It was found that the samples with the composition (1% Roller Kiln, 35% Ceramic tiles sludge, and 64% Floor tiles mixture) or (2% Roller Kiln, 24% Ceramic tiles sludge, and 74% Floor tiles mixture) have the optimum properties.

Fixed-bed column for the removal of cesium, strontium, and lead ions from aqueous solutions using brick kiln waste

ABSTRACTFixed-bed column was employed for the dismissal of strontium, cesium, and lead cations by the waste of brick kiln as a low-cost adsorbent. Brick kiln waste was characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Thermal Gravimetric Analysis (TGA) & Differential Thermal Analysis (DTA), and particle size analyzer. The column performance was 80.1%, 73.6%, and 68.5% for Pb2+, Cs+, and Sr2+, respectively. Scale-up of continuous processes was studied by applying some kinetic column models. Exhausted bed was regenerated using 0.2 mol/L HNO3 and multiple reused for further sorption which is necessary for the industrial applications and maintenance cost of the adsorption treatment plant. The process is simple, eco-efficient, and environmentally friendly.

Suitability of brick kiln waste as a stabilizer to clayey soils

Due to increased use of brick masonry for construction of buildings in Pakistan, huge quantities of Brick Kiln Waste (BKW) are generated which not only create disposal problems but are a hazard to the environment. In order to get rid of such problems, it is necessary to investigate suitability of the BKW as a stabilizer to the clayey soils. For this purpose, an experimental program was carried out to stabilize clayey soil with the BKW ranging from 5 to 40%. Basic geotechnical tests were performed on the clayey soil blended with the BKW. The results showed that the clayey soil became coarser and more suitable as a subgrade material with addition of the BKW. There was negligible reduction in dry density up to 7% when the BKW added was 40%. As expected, the cohesion and friction angle of the blended soils respectively decreased and increased with inclusion of the BKW. As compared to the clayey soil, the ultimate bearing capacity of the blended soil having 40% of the BKW increased by 21%. This study shows that clayey soils stabilized with the BKW could be used as a partial fill material for highway embankments and foundations of buildings.

Fabrication of ceramic membranes from nano–rosette structure high alumina roller kiln waste powder for desalination application

In the manufacture of some ceramic products, in particular wall and floor tiles, roller kilns are used for firing. In this work, the kiln rollers grind waste is recycled and used as raw material in the production of ceramic membranes for use in water filtration. The powder waste was analyzed by XRF for chemical composition, XRD for mineralogical composition, DTA and TGA for thermal behavior, TEM, particle size distribution, and powder density. It was determined that the particles are nano–sized and have rosette–like segregations structure.Ceramic membranes were prepared by in disc form using an organic binder (PVA) with concentrations ranging from 2% to 8% by weight. They were subsequently pressed at 25 MPa, dried and fired at firing temperatures ranging from 1100° to 1300°C for 1, 2, and 3 h soaking time. The following properties were then investigated; Apparent and closed porosity, bulk density, water absorption and desalination performance. It was found that the best properties were obtained on firing the prepared ceramic membranes at 1250 °C, where salt separation percentage reached 99% with a flux of 244.5 L m−2 h−1 using a solution of salt concentration 5000 ppm.

The generation of power from a cement kiln waste gases: a case study of a plant in Kenya

AbstractThe cement production process is energy intensive both in terms of the thermal energy (firing the kiln, drying and De carbonation) and electrical energy for driving the numerous drives within the process line. The average specific power consumption of the case study plant was 111 kWh/ton of cement with an average peak demand of 9.7 MW. The high cost of electric power at 0.14 USD/kWh results in very high cost of production that significantly lowers the company's profit margin and limits its competitive advantage. The generation of electrical power from waste heat recovery would reduce the electricity power bill through partially substituting the power procured from the national grid. This research evaluated the potential that the plant has for generating electrical power from the hot waste gases vented into the atmosphere and it was found that the plant has the potential to generate 3.4 MWh of electrical power. This results to a net potential to generate 2.89 MWh of electrical power after factoring in the auxiliary power consumption by Waste heat recovery plant system at 15%. This ultimately gave a reduction of 33% in the electricity power bill of the case study plant. The paper recommends the installation of a steam rankine cycle for the power generating plant. In this work the authors designed the steam boilers for the waste heat recovery plant for conversion of thermal energy to electrical energy, selected a commercial steam turbine and evaluated its economic feasibility and established that the designed plant would have a simple payback period of 2.7 years.

The enrichment of an alkaliphilic biofilm consortia capable of the anaerobic degradation of isosaccharinic acid from cellulosic materials incubated within an anthropogenic, hyperalkaline environment.

Anthropogenic hyperalkaline sites provide an environment that is analogous to proposed cementitious geological disposal facilities (GDF) for radioactive waste. Under anoxic, alkaline conditions cellulosic wastes will hydrolyze to a range of cellulose degradation products (CDP) dominated by isosaccharinic acids (ISA). In order to investigate the potential for microbial activity in a cementitious GDF, cellulose samples were incubated in the alkaline (∼pH 12), anaerobic zone of a lime kiln waste site. Following retrieval, these samples had undergone partial alkaline hydrolysis and were colonized by a Clostridia-dominated biofilm community, where hydrogenotrophic, alkaliphilic methanogens were also present. When these samples were used to establish an alkaline CDP fed microcosm, the community shifted away from Clostridia, methanogens became undetectable and a flocculate community dominated by Alishewanella sp. established. These flocs were composed of bacteria embedded in polysaccharides and proteins stabilized by extracellular DNA. This community was able to degrade all forms of ISA with >60% of the carbon flow being channelled into extracellular polymeric substance (EPS) production. This study demonstrated that alkaliphilic microbial communities can degrade the CDP associated with some radioactive waste disposal concepts at pH 11. These communities divert significant amounts of degradable carbon to EPS formation, suggesting that EPS has a central role in the protection of these communities from hyperalkaline conditions.

Biogeochemical Reduction Processes in a Hyper-Alkaline Leachate Affected Soil Profile

Hyperalkaline surface environments can occur naturally or because of contamination by hydroxide-rich wastes. The high pH produced in these areas has the potential to lead to highly specialized microbial communities and unusual biogeochemical processes. This article reports an investigation into the geochemical processes that are occurring in a buried, saturated, organic-rich soil layer at pH 12.3. The soil has been trapped beneath calcite precipitate (tufa) that is accumulating where highly alkaline leachate from a lime kiln waste tip is emerging to atmosphere. A population of anaerobic alkaliphilic bacteria dominated by a single, unidentified species within the Comamonadaceae family of β-proteobacteria has established itself near the top of the soil layer. This bacterial population appears to be capable of nitrate reduction using electron donors derived from the soil organic matter. Below the zone of nitrate reduction a significant proportion of the 0.5N HCl extractable iron (a proxy for microbial available iron) is in the Fe(II) oxidation state, indicating there is increasing anoxia with depth and suggesting that microbial iron reduction is occurring. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental files.

Excavations on the site of Balmerino House, Constitution Street, Leith

The remains of the front of Balmerino House (NGR: NT 2711 7616), built in 1631, were uncovered during an archaeological excavation at St Mary's Star of the Sea Roman Catholic Church, Constitution Street, Leith. The work also revealed several phases of medieval to post-medieval activity, and a small burial ground which predated the house. The earliest feature uncovered by the excavation was a well containing 13th- to 14th-century pottery. Large quantities of late to post-medieval pottery were recovered, as well as iron objects, glass and bone. The human remains comprised six adult males, although some were incomplete due to later disturbance. Of importance to the history of clay tobacco pipe manufacture in Scotland is a small assemblage of clay-pipe wasters and kiln waste dated c 1630–40.

Western Marmarica Coastal Survey 2008: a preliminary report

AbstractThis paper reports the preliminary results of a brief survey east of Tobruk over Easter 2008. The survey concentrated upon two areas: between Wadi Qseirat and Wadi Gabar, north of Kambut and around Marsa Lukk. Thirty-four sites were identified, ranging from larger settlements near good harbours (one each at Wadi Duma and Marsa Lukk), to farmsteads, farms and larger inland villages. Eleven sites provided evidence of industrial activity through the presence of kiln waste and at four of them, of the kilns themselves. Dated sites belong to the Early and Late Roman periods, Iron Age and Hellenistic sherds are present in small quantities. Marmaric ware, first identified along the coast of the western desert of Egypt, is shown to extend into this area and may be associated with cairn and enclosure burials.

Analysis of transport phenomena in a rotary-kiln hazardous waste incinerator

Processing of hazardous waste in a rotary kiln incinerator is a complex process. Since hazardous waste has often very complicated chemical compositions and physical forms, the transport phenomena within the incinerator are not well understood, and the incineration process expects large uncertainties in process chemistry and is difficult for emission control. For better understanding of the incineration process, various transport phenomena taking place in the rotary kiln were discussed and analysed in this paper. To get more quantitative understanding, process simulation was conducted by using Computational Fluid-Dynamics (CFD) to characterise gas and solid flow and mixing, temperature and species distribution in the incinerator. To include all the waste streams in a single CFD model is a difficult task, and how to define the different waste streams with different calorific values and chemical compositions is a challenge to the CFD modelling. In this study, hazardous waste in various forms is firstly converted to a hydrocarbon-based virtual fuel mixture based on an overall mass and energy balance. The combustion of the simplified waste was then simulated with a combustion model. The distribution of temperature and chemical species is broadly investigated under various conditions. The predicted temperature distribution has been validated with available measurement data from an operating rotary kiln waste incinerator, and reasonable agreement between the predicted and measured data has been reached.