Life Cycle Assessment of Comprehensive Utilization of Calcium Carbide Slag in Cement Kiln

2020 ◽  
Vol 993 ◽  
pp. 1487-1495
Author(s):  
Xin Ping Lin ◽  
Ai Wei Liu ◽  
Yun Fa Feng ◽  
Qi Ling Chen ◽  
Tao Chen ◽  
...  

The recycling utilization of solid waste is an important technical means for the sustainable development of the cement industry in China. Calcium carbide slag is a special solid waste in China, which can be used for cement production with a great advantage on CO2 emission reduction. With an view to providing methodological and data support for the development of policies in the cement industry, this paper quantitatively analyzes the environmental effects/environmental benefits of the comprehensive utilization of calcium carbide slag in cement kiln by comparing the traditional system of Portland cement clinker completely produced by natural resources with the system of cement clinker produced by calcium carbide slag based on the life cycle assessment (LCA) method given in standards and specifications of ISO 14040 series. The results show that the latter system has a better effect in material saving and carbon emission reduction, will increase the energy consumption in cement production process, and also slightly increase other pollutants (e.g. SOx, NOx, etc.) emission. The GWP, AP and EP indicators of the calcium carbide slag cement clinker system decrease compared with those of the Portland cement clinker system, while other indicators do not differ much or even slightly increase.

2021 ◽  
Vol 1035 ◽  
pp. 988-998
Author(s):  
Yu Chen Zhang ◽  
Xian Zheng Gong ◽  
Yu Liu ◽  
Li Wei Zhou

Based on the analysis of the development situation of China’s cement industry and the BCG Matrix method, this paper classifies and screens 31 energy-saving technologies in China's cement production, and puts forward guiding suggestions for the application of energy-saving technologies for cement enterprises. The screening results show that the “Energy-efficient powder separation technology” and “New low-calcium cement clinker and production technology” are “double-high” technologies with excellent on both screening indicators. The investment energy saving rates are 17.5 tce/10,000 yuan (tons of standard coal equivalent per 10,000 yuan) and 10 tce/10,000 yuan. The promotion ratio increments are 35% and 25%. “Cement clinker energy-saving nitrogen reduction firing technology”, “Fan drive mode adopts high voltage frequency conversion speed control technology”, “Pure low temperature waste heat power generation technology for cement kiln” are “single-high” technologies with excellent on one of screening indicators. The investment energy saving rates are 0.3tce/10,000 yuan, 4.1tce/10,000 yuan, 3.9tce/10,000 yuan respectively. The promotion ratio increments are 19%, 35%, 31.5% respectively.


2013 ◽  
Vol 743-744 ◽  
pp. 516-522 ◽  
Author(s):  
Fei Fei Shi ◽  
Zhi Hong Wang ◽  
Ming Hui Fang ◽  
Bo Xue Sun ◽  
Ming Nan Zhao ◽  
...  

With the development of economy, China has become one of the largest cement producers in the world. However, cement industry is a main contributor of global carbon emissions. Substituting calcium carbide sludge for limestone is an effective method for CO2 emission reduction in cement industry and has developed rapidly in recent years in China. The purpose of this study is to determine the life cycle CO2 emission of cement clinker produced with calcium carbide sludge as secondary raw material. The results show that compared with general cement clinker, the life cycle CO2 emission intensity of cement clinker produced with calcium carbide sludge will be decreased by 39.1% when substitution rate is 80%. And the CO2 emission results from the procedure of cement clinker production accounts for 85.7% of the total emission, in this stage, the CO2 emission declined by 42.2%.


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.


2014 ◽  
Vol 599 ◽  
pp. 324-327 ◽  
Author(s):  
Jia Ping Cui ◽  
Yu Liu ◽  
Zhi Hong Wang ◽  
Li Li Zhao ◽  
Fei Fei Shi ◽  
...  

The environmental impacts of cement production using two pre-drying processes, i.e., coal-fired pre-drying process and pre-drying process by waste heat from kiln tail process were analyzed and compared through life cycle assessment (LCA). The results show that the energy consumption, GWP, AP, POCP, HT and EP of pre-drying process by waste heat from kiln tail are about 1%, 2%, 5.2%, 5% ,3.5% and 3.8% lower than coal-fired process; therefore the application of pre-drying process by waste heat from kiln tail has obvious environmental benefits.


2013 ◽  
Vol 389 ◽  
pp. 341-345 ◽  
Author(s):  
Ya Li Wang ◽  
Shi Jie Dong ◽  
Lin Lin Liu ◽  
Su Ping Cui ◽  
Hai Bo Xu

Calcium carbide Slag is one kind of industrial wastes from CaC2 hydrolysis reaction that will cause land pollution. In the research, calcium carbide Slag used as a substitute for limestone to produce cement clinker, which with a high portion of CaO content and then an excellent calcium containing raw material. As a kind of industrial wastes, the properties of Calcium carbide slag differentiate from that of natural limestone. The formation process of clinker minerals was studied by means of XRD. The results indicated that clinker minerals formation is similar to that from use of limestone. The generated clinker has a rational mineral composition and well developed mineral phase structure. But, there are many differences in decomposition temperatures between the calcium containing raw materials. Therefore, the carbide slag can be used as a substitute of limestone raw material to produce cement clinker.


2018 ◽  
Vol 68 (331) ◽  
pp. 166
Author(s):  
S. Chhaiba ◽  
M. T. Blanco-Varela ◽  
A. Diouri

For some time the cement industry has been seeking procedures to effectively lower the higher energy costs involved in cement manufacture. Timahdit oil shale and Jerada coal waste could potentially be used as alternative raw materials to produce clinker. This study explored the possibility of applying those materials to a greener use, based on the reactivity and burnability of raw mixes containing Moroccan oil shale and coal waste. The findings showed that, irrespective of particle size, oil shale mixes delivered higher reactivity than coal waste materials, although reactivity was highest in the oil shale clinker with a particle size < 45 μm. The clinkers bearing oil shale with a particle size < 90 μm or a blend of oil shale and coal waste with a size < 45 μm contained higher proportions of alite ( > 70 %).


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Li Luo ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Tiejun Chen

The cement industry has for some time been seeking alternative raw material for the Portland cement clinker production. The aim of this research was to investigate the possibility of utilizing iron ore tailings (IOT) to replace clay as alumina-silicate raw material for the production of Portland cement clinker. For this purpose, two kinds of clinkers were prepared: one was prepared by IOT; the other was prepared by clay as a reference. The reactivity and burnability of raw meal, mineralogical composition and physical properties of clinker, and hydration characteristic of cement were studied by burnability analysis, differential thermal analysis, X-ray diffraction, and hydration analysis. The results showed that the raw meal containing IOT had higher reactivity and burnability than the raw meal containing clay, and the use of IOT did not affect the formation of characteristic mineralogical phases of Portland cement clinker. Furthermore, the physical and mechanical performance of two cement clinkers were similar. In addition, the use of IOT was found to improve the grindability of clinker and lower the hydration heat of Portland cement. These findings suggest that IOT can replace the clay as alumina-silicate raw material for the preparation of Portland cement clinker.


2013 ◽  
Vol 743-744 ◽  
pp. 171-174 ◽  
Author(s):  
Ya Li Wang ◽  
Shi Jie Dong ◽  
Lin Lin Liu ◽  
Su Ping Cui

Calcium carbide Slag is from CaC2 hydrolysis reaction and will do harm to land and make pollution. Calcium carbide slag can be a substitute for limestone to produce clinker with a high portion of CaO as an excellent calcium raw material. As a kind of industrial wastes, the properties of calcium carbide slag differentiate from that of natural limestone. In the present investigation, the modern analysis methods of XRF, XRD, DTA/TG, petrographic analysis were used to compare carbide slag and limestone, and the results showed that the main chemical compositions of the calcium carbide slag were basically the same with that of natural limestone. Comparing with limestone materials, calcium carbide slag had a higher content of CaO, and the main mineral phase constituent of limestone was CaCO3, whereas the main mineral of calcium carbide slag was Ca (OH)2 with a lower decomposition temperature. It has been found that under the same temperature the amount of C3S in the clinker of calcium carbide slag batching was slightly less than that of limestone batching.


2014 ◽  
Vol 599 ◽  
pp. 98-102 ◽  
Author(s):  
Jiang Feng Li ◽  
Xiu Cheng Luo ◽  
Meng Ke Sun ◽  
Wei Guo Shen ◽  
Bing Cao ◽  
...  

The production of steel slag, a byproduct of the steel refining keeps increasing rapidly and it reached 90.42 million tons in 2011 in China, but its comprehensive utilization ratio is only 22% and far less than the ratio of 65% in Europe. Main chemical compositions of steel slag are CaO, SiO2, Al2O3, FeO, Fe2O3, MgO, MnO, P2O5 and so on, C3S, C2S, C3MS2, RO phase are its common minerals. Due to its high reactivity and Ferro content, steel slag has high potential utilization as supplementary hydraulic cementitious materials or cement clinker meal in cement industry. A method of multiple phased sintering was presented, it can break through the bottlenecks for the steel slag using in the cement industry, e.g. volume stability and grindability ,the carbon emission of cement industry is slashed, it is an effective new approach to massively utilize steel slag in cement industry.


2016 ◽  
Vol 27 (2) ◽  
pp. 178-193 ◽  
Author(s):  
Nickolaos Chatziaras ◽  
Constantinos S. Psomopoulos ◽  
Nickolas J. Themelis

Purpose – Cement production has advanced greatly in the last few decades. The traditional fuels used in traditional kilns include coal, oil, petroleum coke, and natural gas. Energy costs and environmental concerns have encouraged cement companies worldwide to evaluate to what extent conventional fuels can be replaced by waste materials, such as waste oils, mixtures of non-recycled plastics and paper, used tires, biomass wastes, and even wastewater sludge. The paper aims to discuss these issues. Design/methodology/approach – The work is based on literature review. Findings – The clinker firing process is well suited for various alternative fuels (AF); the goal is to optimize process control and alternative fuel consumption while maintaining clinker product quality. The potential is enormous since the global cement industry produces about 3.5 billion tons that consume nearly 350 million tons of coal-equivalent fossil and AF. This study has shown that several cement plants have replaced part of the fossil fuel used by AF, such waste recovered fuels. Many years of industrial experience have shown that the use of wastes as AF by cement plants is both ecologically and economically justified. Originality/value – The substitution of fossil fuels by AF in the production of cement clinker is of great importance both for cement producers and for society because it conserves fossil fuel reserves and, in the case of biogenic wastes, reduces greenhouse gas emissions. In addition, the use of AF can help to reduce the costs of cement production.


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