Evaluation of Green Cement Manufacturing Seeking Joint Treatment for Urban Refuse

2013 ◽  
Vol 567 ◽  
pp. 143-148 ◽  
Author(s):  
Yue Qin Tang

Sanitary landfill, Burning, Compost are the main method to dispose gabage in China.If urben refuse is put into the cement kiln, processing it, producing cement, it will benefit all. This mature method has no influence on neither the cement production nor the quality of cement products,however the indexes of all emissions in the manufacturing meet the national standards. Statistics show the heat generated by every ton of waste is equal to that of 183kg standard coals; the cinders are mixed in cement during the treatment process, thus 107kilograms substitute raw materials can be generated by every ton of waste, and 6 to 7 percent are added. Moreever, it reduces carbon dioxide emission 8000 tons for every 10,000 tons waste. This paper concludes: the utilization of cement kiln to incinerate domestic waste has obvious advantages in environmental protection and total investment does not cost much. The municipal engineering construction has the priority to use the products from domestic treatment cement factories, and domestic waste incineration cement factories should be under self-management. Also supportive policies as well as the readjustment of waste treatment management and interest pattern can promote the development of treating urban domestic waste by cement production.

2020 ◽  
Vol 12 (6) ◽  
pp. 2500 ◽  
Author(s):  
Li Ping ◽  
Gang Zhao ◽  
Xiaohu Lin ◽  
Yunhui Gu ◽  
Wei Liu ◽  
...  

Cement manufacturing and the treatment of sludge are considered both energy-intensive industries and major greenhouse gas (GHG) emitters. However, there are still few studies on comprehensive carbon footprint analysis for adding municipal sludge in the cement production. In this study, the lime-dried sludge blended with calcium oxide at the mass mixing ratio of 10% was utilized as raw material for the preparation of Portland cement. The chemical and physical properties of sludge were analyzed. A set of carbon footprint calculation methods of lime-drying treatment of sludge and reuse in cement kilns was then established to explore the feasibility of coprocessing lime-dried sludge in cement kilns. The results showed lime-dried sludge containing CaO, SiO2, Al2O3, and Fe2O3 was ideal for cement production as raw material. However, the water content of lime-dried sludge should be strictly limited. The lime-drying process presented the biggest carbon emission (962.1 kg CO2-eq/t sludge), accounting for 89.0% of total emissions. In the clinker-production phase, the lime-dried sludge as raw material substitute and energy source gained carbon credit of 578.8 and 214.2 kg CO2-eq/t sludge, respectively. The sludge used for producing cement clinker could reduce carbon emissions by 38.5% to 51.7%. The addition ratio of lime and stacking time in the sludge lime-drying process could greatly affect the carbon footprint of coprocessing lime-dried sludge in cement kiln.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
MARIJA HADŽI-NIKOLOVA ◽  
DEJAN MIRAKOVSKI ◽  
NIKOLINKA DONEVA ◽  
NATAŠA BAKRESKA

The main environmental issues associated with cement production are the consumption of raw materials, energy use and emissions in the air. Noise emissions occur throughout the whole cement manufacturing process - from preparing and processing raw materials, from the clinker burning and cement production process, from material storage as well as from the dispatch and shipping of the final products. The heavy machinery and large fans used in the cement manufacturing process can give rise to noise emissions. Cement Plants are required to comply with standards for reduction in line with national legislation, and to conduct measurements and perform noise surveys. Having this in mind, A TITAN Group Usje Cement Plant in Skopje, following their strong commitment to high environmental performance and Corporate Social Responsibility and Sustainable Development Policy in 2013-2014 have engaged an AMBICON Lab (Faculty of Natural and Technical Sciences) from Stip, to conduct a Noise Control Study in order to identify noise sources within cement plant and marl quarry, determine their impacts on nearby residents and develop noise control/protection strategies. During the past three years, the Usje Cement plant has implemented most of the noise control measures proposed in this Study. Also, a follow-up study during 2016-2017 was conducted in order to assess the effectiveness of measures taken. This paper presents the outcomes of noise reduction measures taken. Keywords: noise, cement industry, process management, measures, environment


2011 ◽  
Vol 10 (1) ◽  
pp. 93
Author(s):  
Prasticia chandra Dewi

Cement manufacturing is consisting of four components that are limestone with the percent composition of 70%, iron sand 10%, silica 10%, and clay 10%. Source of major raw materials for cement production in PT Semen Padang are limestone and silica. The mining process is involving various costs such as direct costs, indirect costs, overhead costs, etc. Therefore, cost calculations needed to determine the selling price of produced silica. In calculating the cost of production considered various aspects, such as operating costs, material costs, labor costs. So that, it can determine cost of goods production. The research objective is calculating cost of goods manufacturing the silica. Benefit of the research for PT Semen Padang is describing cost of goods production in determining cost of goods sold. Cost of goods production that resulted for silica mining is IDR 58.000 per ton, while internal price of silica is IDR 53.851 per ton. Research result is show that there is difference between results based on Full costing method with current price. This shows that several other factors is necessary considered in calculating the cost of goods production. Keywords: Mining, silica, cost of goods production


2019 ◽  
Vol 117 (23) ◽  
pp. 12584-12591 ◽  
Author(s):  
Leah D. Ellis ◽  
Andres F. Badel ◽  
Miki L. Chiang ◽  
Richard J.-Y. Park ◽  
Yet-Ming Chiang

Cement production is currently the largest single industrial emitter of CO2, accounting for ∼8% (2.8 Gtons/y) of global CO2emissions. Deep decarbonization of cement manufacturing will require remediation of both the CO2emissions due to the decomposition of CaCO3to CaO and that due to combustion of fossil fuels (primarily coal) in calcining (∼900 °C) and sintering (∼1,450 °C). Here, we demonstrate an electrochemical process that uses neutral water electrolysis to produce a pH gradient in which CaCO3is decarbonated at low pH and Ca(OH)2is precipitated at high pH, concurrently producing a high-purity O2/CO2gas mixture (1:2 molar ratio at stoichiometric operation) at the anode and H2at the cathode. We show that the solid Ca(OH)2product readily decomposes and reacts with SiO2to form alite, the majority cementitious phase in Portland cement. Electrochemical calcination produces concentrated gas streams from which CO2may be readily separated and sequestered, H2and/or O2may be used to generate electric power via fuel cells or combustors, O2may be used as a component of oxyfuel in the cement kiln to improve efficiency and lower CO2emissions, or the output gases may be used for other value-added processes such as liquid fuel production. Analysis shows that if the hydrogen produced by the reactor were combusted to heat the high-temperature kiln, the electrochemical cement process could be powered solely by renewable electricity.


2019 ◽  
Vol 11 (2) ◽  
pp. 537 ◽  
Author(s):  
Ali Naqi ◽  
Jeong Jang

The cement industry is facing numerous challenges in the 21st century due to depleting natural fuel resources, shortage of raw materials, exponentially increasing cement demand and climate linked environmental concerns. Every tonne of ordinary Portland cement (OPC) produced releases an equivalent amount of carbon dioxide to the atmosphere. In this regard, cement manufactured from locally available minerals and industrial wastes that can be blended with OPC as substitute, or full replacement with novel clinkers to reduce the energy requirements is strongly desirable. Reduction in energy consumption and carbon emissions during cement manufacturing can be achieved by introducing alternative cements. The potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies. Seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed. The study provides a comprehensive analysis of options for future cements, and an up-to-date summary of the different alternative fuels and binders that can be used in cement production to mitigate carbon dioxide emissions. In addition, the practicalities and benefits of producing the low-cost materials to meet the increasing cement demand are discussed.


2020 ◽  
Vol 993 ◽  
pp. 1527-1533
Author(s):  
Xue Yang ◽  
Xin Ping Lin ◽  
Yan Jing Wang ◽  
Yu Liu ◽  
Li Wei Hao ◽  
...  

The annual output of domestic waste has exceeded 400 million tons in China since 2016, which causes an urgent demand on harmless disposal in the current rapid process of urbanization. Compared with traditional disposal means (e.g. incineration and landfill), co-processing with cement production seems to be a better chose to meet the requirements of domestic waste treatment (i.e. harmless, volume reduction, waste utilization). However, co-processing technology also has some negative impact (e.g. extra energy consumption for pretreatment of domestic waste), so the environmental feasibility of domestic waste co-processing in cement kiln should be verified. In this paper, the influences caused by domestic waste co-processing on the cement clinker products including resource/energy consumption, as well as the pollutant emissions were quantify based on the investigation of typical plants in China. Moreover, the environment impact between landfill treatment and co-processing scenario were compared using life cycle assessment (LCA) method. The result shows that the energy consumption and CO2 emission per ton cement clinker production increased by 3.6% and 0.8% after co-process domestic waste, respectively. Furthermore, compared with sanitary landfill treatment, the co-processing in cement kiln will increase the impact of FFP, but reduce GWP and HTP impacts, especially significantly decrease the impact of LOP and SOP, bring in a good beneficial on material saving and energy saving.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
S. P. Dunuweera ◽  
R. M. G. Rajapakse

We first discuss cement production and special nomenclature used by cement industrialists in expressing the composition of their cement products. We reveal different types of cement products, their compositions, properties, and typical uses. Wherever possible, we tend to give reasons as to why a particular cement type is more suitable for a given purpose than other types. Cement manufacturing processes are associated with emissions of large quantities of greenhouse gases and environmental pollutants. We give below quantitative and qualitative analyses of environmental impact of cement manufacturing. Controlling pollution is a mandatory legal and social requirement pertinent to any industry. As cement industry is one of the biggest CO2 emitters, it is appropriate to discuss different ways and means of CO2 capture, which will be done next. Finally, we give an account of production of nanocement and advantages associated with nanocement. Nanofillers such as nanotitania, nanosilica, and nanoalumina can be produced in large industrial scale via top-down approach of reducing size of naturally available bulk raw materials to those in the nanorange of 1 nm–100 nm. We mention the preparation of nanotitania and nanosilica from Sri Lankan mineral sands and quartz deposits, respectively, for the use as additives in cement products to improve performance and reduce the amount and cost of cement production and consequent environmental impacts. As of now, mineral sands and other treasures of minerals are exported without much value addition. Simple chemical modifications or physical treatments would add enormous value to these natural materials. Sri Lanka is gifted with highly pure quartz and graphite from which silica and graphite nanoparticles, respectively, can be prepared by simple size reduction processes. These can be used as additives in cements. Separation of constituents of mineral sands is already an ongoing process.


2018 ◽  
Vol 280 ◽  
pp. 481-486 ◽  
Author(s):  
Teewara Suwan

Geopolymer cement is an aluminosilicate material which activated by the alkaline solution. With appropriate heat curing regimes, geopolymer cement could achieve an excellent performance as construction material. Apart from that, geopolymer cement is one of the alternative cementitious materials for green construction as its raw starting materials could be any pozzolanic industrial by-products. Global carbon-dioxide emission from Portland cement consumption could be reduced with the replacement of that geopolymer cement. Therefore, the development of geopolymer cement is receiving much more attention. However, various kinds of materials have been used as geopolymer precursors. The main aim of this paper is, thus, to summarize current information on the usage of raw materials in geopolymer production by categorize its types and sources. The summarised details of chemical composition and compressive strength could provide a guide line for readers to evaluate possible reactions or outputs of their selected local raw materials as well as the prediction of material’s combination for the improvement of targeted strength of each possible prime material.


2015 ◽  
Vol 768 ◽  
pp. 135-141 ◽  
Author(s):  
Ye Qing Li ◽  
Huan Zhong Wang ◽  
Jiang Zhang ◽  
Song Bai Yu ◽  
Wen Juan Miao

The national general survey manifests that the Chinese soil is suffering from serious contamination, mainly arising from heavy metals (HM). Due to the large amount of heavy metal waste, many researchers have performed the feasibility studies on co-processing this kind of waste in cement kilns. In this paper, we review these results from the perspectives of national standards, the crystal structure of clinker, and the volatility of metals in cement kiln system. The crystal structure of clinker mineral offers physical possibility for the solidification of HM atoms. The volatility studies also indicate that most of the metals will not emit from the kiln system. For the incorporated metals in clinker, their release ratio is very low, and the leaching HM atoms can be immediately enclosed by the cement hydration products. Based on these theoretical results, we measured the HM in the raw materials and in the cement product for 1 year in a cement plant. The bag filter dust contained high level of Tl with an average of 219.30 ppm. The other metals were almost solidified by the clinker. With the vaporization of Tl in the raw materials, the circulation pattern causes the accumulation and buildup of Tl in the system. The incorporation capacity of clinker on HM is predicted in this paper, but the incorporation ratio of HM from contaminated soil, the circulation pattern of HM in cement kiln system, and the emission of HM is currently not clear and further work is in progress.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Protus Nalobile ◽  
Jackson Muthengia Wachira ◽  
Joseph Karanja Thiong’o ◽  
Joseph Mwiti Marangu

Pyroprocessing is an important stage in cement manufacturing. In this process, materials are subjected to high temperatures so as to cause a chemical or physical change. Its control improves efficiency in energy utilization and hence enhances production for good quality assurance. Kilns used in cement manufacturing are complex in nature. They have longer time constants, and raw materials used have variable properties. They are therefore difficult to control. Additionally, the inclusion of various alternative fuels in burning makes the process more complex as the fuel characteristics remain inconsistent throughout the kiln operation. Fuel intensity standards for kilns using fuel oil are very high, ranging from 2.9 GJ to 7.5 GJ/ton of clinker produced. Grinding of clinker consumes power in the range of 2.5 kWh/ton of clinker produced. These and other pyroprocessing parameters make cement production costly. The pyroprocessing process in kilns and the grinding technologies therefore have to be optimized for best processing. This paper discusses the cement manufacturing and grinding processes. The traditional kiln technologies and the current and emerging technologies together with general fuel and energy requirements of cement manufacturing have been discussed. From the discussion, it has been established that the cement manufacturing and grinding technologies are capital-intensive investments. The kiln processes are advanced and use both electricity and natural fuels which are expensive and limited factors of production. The raw materials used in cement manufacturing are also limited and sometimes rare. The calcination of the raw materials requires external energy input which has contributed to the high cost of cement especially to low-income population in the developing countries. Self-calcining materials, in which the pozzolanic materials burn on their own, are potential pozzolanic materials with great potential to lower the cost of cement production. Such materials, as shown from the previous research study, are rice husks, broken bricks, spent bleaching earth, and lime sludge. There is a need, therefore, for research to look into ways of making cement using kiln processes that would use this property. This will be cost-effective if successful. It can be done at micro- and small-scale enterprise.


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