scholarly journals Assessment and Characterization of Mine Waste and Fly Ash Material for Effective Utilization in Opencast Coal Mines

2020 ◽  
Vol 9 (1) ◽  
pp. 2490-2500
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Soil Type ◽  
Energy Demand ◽  
Mine Waste ◽  
Liquid Limit ◽  
Unit Weight ◽  
Angle Of Internal Friction ◽  
Planning And Control ◽  
The Impact

Coal is a major source of nonrenewable energy in India. Most of the Industries depend on the coal to meet the energy demand of the country. Coal mining is invariably associated with the generation of voids. The voids so generated are often filled with overburden (OB) and waste materials. To enhance the utilization, fly ash (FA) is also being used for filling the voids. However, these operations inevitably require excessive planning and control to minimize the environmental impact of mining. In order to evaluate the impact of backfilling the voids with coal mine wastes and fly ash, Overburden and fly ash materials have been collected from Talcher coalfield. The geotechnical characterization study of overburden (OB) sample and OB+30% fly ash samples have been carried out separately for backfilling. After addition of fly ash, it is observed that the permeability is increased but liquid limit, plastic limit, and plasticity index (PI) of the OB are decreased. The maximum dry unit weight of OB mixture decreases while optimum water content increases with the fly ash. The angle of internal friction of OB decreases after addition of the fly ash. Cohesion value of OB sample has not changed much after addition of the fly ash. The grain size analyses results show OB sample is poorly graded. The OB soil type is found to be poorly graded sand of low compressible clay (SP-CL). Similarly, the OB+30% fly ash soil type is of poorly graded sand of low compressible silty (SP-ML) type. The OB and OB+ 30% fly ash contain heavy metals such as Fe and Al in high quantity, mild concentrations of Zn, Cr, and Mn and low amounts of Cu, Co, As, and Se. B and Pb are found below the detection level. The decreasing order of heavy metals in the leachate samples observed to be Fe>Mn>Ni>Cu>Zn>Se>Co>Cd>Cr>As. The major mineral phases in OB and OB+30% fly ash samples are found to be quartz, kaolinite, muscovite, dickite, zinnwaldite, and illite.

Influence of Fly Ash Addition on Behavior of Soft Clayey Soil

2020 ◽  
Vol 38 (5A) ◽  
pp. 698-706
Author(s):  
Hussein H. Karim ◽  
Zeena W. Samueel ◽  
Adel H. Jassem
Keyword(s):  
Fly Ash ◽  
Specific Gravity ◽  
Clayey Soil ◽  
Soft Soil ◽  
Cost Effective ◽  
Liquid Limit ◽  
Ash Content ◽  
Unit Weight ◽  
Cost Effective Method ◽  
The Impact

This paper investigates the impact of the fly Ash addition on the Geotechnical properties of soft soil as well as chooses the optimum percentage added of fly ash. To understand the behavior of fly ash mixed with soil, a number of laboratory experiments testing conducted on clayey soil-fly ash mixture in several percentages (5,10,15,20,25, and 30%) as Atterberg test, Specific gravity test, compaction test, California Bearing Ratio (C.B.R) Test, Unconfined Compressive Strength (UCS) Test, Consolidation Test. Test results indicate rising in plastic limit and liquid limit as fly ash adding.  Specific gravity decreased essentially by adding fly ash. Whereas there was falling on the Dry unit weight value with the contract to the decreasing in the water content.  The CBR and UCS values were increased with increasing fly ash content. 20% was the optimum fly Ash content. This study also benefits the effective use of fly ash and thus a cost-effective method for improving the soil properties.

Removal of heavy metals from fly ash and the impact on its quality

2002 ◽  
Vol 77 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Henk W Nugteren ◽  
Maria Janssen-Jurkovícová ◽  
Brian Scarlett
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Removal Of Heavy Metals ◽  
The Impact

Effect of Fly Ash on Compaction Behavior of Alluvial Soil

2021 ◽  
Author(s):  
Abdulmuner Malikzada ◽  
Hasan Fırat Pulat ◽  
İnci Develioğlu
Keyword(s):  
Fly Ash ◽  
Alluvial Soil ◽  
Liquid Limit ◽  
Unit Weight ◽  
Sieve Analysis ◽  
Plastic Limit ◽  
Alluvial Deposits ◽  
Dry Unit Weight ◽  
Compaction Behavior ◽  
Engineering Projects

Low plasticity, high bearing capacity, low settlement, etc. are the preferred properties for most engineering projects. Alluvial soils are problematic soils because of low bearing capacity, high organic matter content, and high void ratio so they do not meet the preferred condition for engineering projects. It has been necessary to improve unsuitable materials to make them acceptable for construction. Fly ash (FA) has earlier been used for stabilizing roads due to its high content of calcium and silicate oxides which give puzzolanic properties and thus high compression strength. In this research, fundamental engineering properties, compaction behaviors of three types of (fine, medium, and coarse) alluvial deposits, and the effect of fly ash on compaction behavior of these alluvial soils are presented. Alluvial soil is taken from Çiğli, Balatçık (Izmir, Turkey). To determine geotechnical index properties; wet sieve analysis, plastic limit, liquid limit, specific gravity, standard compaction tests were conducted. In order to determine the effect of fly ash on compaction behavior of alluvial deposits, three different samples (fine < 0.425mm, medium < 2mm, and coarse < 4.75 mm) are prepared and 10%, 15%, 20% fly ash by dry weight of soil is mixed and standard proctor test is performed. As a result of laboratory tests, the liquid limit, plastic limit, and plasticity index values obtained as 38.3%, 25.7%, and 12.6%, respectively. The specific gravities for fine, medium, and coarse samples are 2.68, 2.67, and 2.66, respectively. According to the results of wet sieve analysis and consistency limit tests, it was stated that the soil contains large amounts of sand and clay. The washed sieve analysis and consistency limit tests results were evaluated according to USCS. The conducted test results have shown that maximum dry unit weight for fine, medium, and coarse soils are 16.9, 19.35, and 19.55 (kN/m3), and optimum moisture content for fine, medium, and coarse samples are 17, 11, 10.5% respectively. Generally, by increasing the content of FA, maximum dry unit weight decreased and optimum moisture content increased for all three types of alluvial soil. By increasing FA to 20%, maximum dry unit weight of medium and coarse soils decreases 1.5% and 2%, respectively.

scholarly journals Improving the Characteristics of a Soft Clay Soil Using Cement Activated Low-Calcium Fly Ash

2021 ◽  
Vol 14 (3) ◽  
pp. 8-22
Author(s):  
Qutaiba Majeed ◽  
Abdalla M Shihab M Shihab ◽  
Jasim M. Abbas ◽  
Saad Sh. Sammen
Keyword(s):  
Fly Ash ◽  
Clay Soil ◽  
Soft Clay ◽  
Unit Weight ◽  
Experimental Program ◽  
Dry Density ◽  
Unconfined Compression Test ◽  
Angle Of Internal Friction ◽  
Low Calcium ◽  
Geotechnical Characteristics

In this research, the potential improvement of some geotechnical characteristics of soft clay soil using the low Calcium fly ash was evaluated. (These characteristics include unit weight, shear strength, compaction characteristics and soil plasticity characteristics). In addition, the X-ray diffraction test was performed to measure the mineralogical changes in the soft clay soil when the low Calcium fly ash is added. The ordinary Portland cement was used to activate the fly ash. The total percent of flash and cement was10% to investigate the variation in the effectiveness of activation. The optimum moisture content that which computed by the compaction test was adopted in the rest of the experimental program. The test results revealed that the cement could be used to improve the activating of the fly ash efficiently. The maximum value of dry density was marginally affected due to activation from 1.747 to 1.738 g/cm3 along with a corresponding change in optimum water content from 17.45 to 15.5 %. The soil cohesion parameter increased from 188 to 206 kN/m2 whereas the angle of internal friction rose from about 56.7o to 59.1o. Finally, the results of the unconfined compression test reveal that the cement-activated fly ash could present better results than those obtained from a 28-days curing cement.

scholarly journals THE ROLE OF BACKFILL QUALITY ON CORRUGATED STEEL PLATE CULVERT BEHAVIOUR

2017 ◽  
Vol 12 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Damian Beben
Keyword(s):  
Numerical Analysis ◽  
Internal Friction ◽  
Steel Plate ◽  
Plate Thickness ◽  
Numerical Calculations ◽  
Unit Weight ◽  
Steel Shell ◽  
Orthotropic Plates ◽  
Angle Of Internal Friction ◽  
The Impact

The subject of the article is a three-dimensional numerical analysis of the impact of backfill quality on the deformation of corrugated steel plate culvert. In the numerical analysis, the author took into consideration three different backfill types. The paper presents the calculations performed with the use of Abaqus program based on finite element method. A steel shell was modelled with the use of the theory of orthotropic plates, and backfill with the use of elastic-perfectly plastic Drucker-Prager model. The author made the numerical calculations under static live loads for the corrugated steel plate culvert with a span of 12.315 m and height of shell of 3.555 m. Soil cover over the shell crown was equal to 1.0 m. The steel shell consisted of the sheets of the corrugation of 0.14×0.38 m and plate thickness of 0.0071 m. The main aim of this paper is to present the impact of backfill quality (internal friction angle, unit weight, Young’s modulus) on the effort of the steel shell. The paper also shows the numerical calculations for the actual culvert, which previously had been studied experimentally. The author compared the obtained numerical results to the results of experiments. Parametric analysis showed that the angle of internal friction was a major factor in corrugated steel plate culverts. Considering the entire width of the corrugated steel plate culvert, the calculation model II was most favourable. The proposed method of modelling of the corrugated steel plate culvert allowed obtaining reasonable values of displacements and stresses in comparison to experimental results.

Analysis of wind resource under heat wave conditions in southern Europe

2021 ◽  
Author(s):  
María Ofelia Molina ◽  
Enrique Sánchez ◽  
Claudia Gutiérrez ◽  
María Ortega
Keyword(s):  
Energy Demand ◽  
Heat Waves ◽  
Energy System ◽  
High Energy ◽  
Planning And Control ◽  
High Penetration ◽  
Using Data ◽  
And Control ◽  
Wind Resource ◽  
The Impact

&lt;p&gt;In recent years, renewable energy is gaining importance in the energy mix, increasing the dependence of the energy system on weather. Atmospheric patterns that affect wind energy production focusing on the winter months have been studied in previous works, as wind resource in Europe is higher for this season, but also because it is when there is a greater and more stable heating demand in Europe. Southern European countries, however, present summer demand increases due to the cooling needs of these countries (Spain, Portugal , Italy and Greece). These increases have been seen with real daily demand data from ENTSO-E (the European Network of Transmission System Operators for Electricity). Demand in Spain is even higher on days of heat waves in the 2015-2018 period, reaching in that case the annual maxima. The objective of this work is to study the wind patterns in these episodes of heat waves. Reduced overall summer wind power supply coupled with high energy demand under these conditions could be compromised. We will analyse means of daily wind anomalies on days of heat waves (composites) using data from the ERA5 reanalysis and the E-OBS temperature observations. The study of the wind resource in conditions of high energy demand due to extreme climate events, can help in the energy supply strategic planning and control to minimize the impact of these events on an electricity system with high penetration of renewables.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Eluviation and Leaching of Elements from Broken Fly-Ash-Based Porous Geopolymer

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6884
Author(s):  
Peng Shi ◽  
Yuan Zhang ◽  
Qingfu Sun ◽  
Xupeng Ta
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Groundwater Quality ◽  
Ph Value ◽  
Quality Standard ◽  
Class Iii ◽  
Liquid Ratio ◽  
Solid Liquid ◽  
The Impact ◽  
Cu And Zn

The fly ash from powerplants used for coal mine end backfilling can effectively reduce the impact of ground fly ash accumulation on the environment. However, due to the long-term action of the overlying strata and groundwater, when the backfilling body is broken, heavy metals will also be leached, thus having an impact on the groundwater. Therefore, in this paper, the eluviation and leaching of elements from a broken fly-ash-based porous geopolymer is studied. The fly-ash-based geopolymer material was prepared to perform a dynamic eluviation and static leaching test, and it was found that the amount of Cu and Zn in the leachate was less abundant, whereas Pb was more abundant, but far less than the limit of the Class III groundwater quality standard. An acidic environment and a smaller solid–liquid ratio can promote the leaching of Cu and Zn, while the leaching of Pb is basically unaffected by the pH value. Moreover, the amount of Cu, Zn, and Pb in the lixivium increased with the increase in leaching time, and the amount of Cu and Zn in the lixivium was still low after 150 h of leaching, whereas the amount of Pb was high, approaching the limit value of the Class III groundwater quality standard, showing a tendency to increase after 100 h of leaching. A leaching orthogonal experiment was designed, and the results showed that the main order of each factor affecting the leaching of heavy metals from the fly-ash-based geopolymer was grain size > pH > solid–liquid ratio; thus, the leaching of heavy metals from fly-ash-based geopolymer can be controlled, which is significant with respect to the extensive use of fly-ash materials underground.

Агрономическая эффективность промышленной (голландской) технологии возделывания картофеля

2018 ◽  
Author(s):  
C. Coy ◽  
A.V. Shuravilin ◽  
O.A. Zakharova
Keyword(s):  
Heavy Metals ◽  
Regression Analysis ◽  
Positive Response ◽  
Growth Yield ◽  
Correlation And Regression Analysis ◽  
Yield And Quality ◽  
Quality Of Products ◽  
High Degree ◽  
The Impact

Приведены результаты исследований по изучению влияния промышленной технологии возделывания картофеля на развитие, урожайность и качество продукции. Выявлена положительная реакция растений на подкормку K2SO4 в период посадки. Корреляционно-регрессионный анализ урожайности и качества клубней выявил высокую степень достоверности результатов опыта. Содержание нитратов и тяжелых металлов в клубнях было ниже допустимых величин.The results of studies on the impact of industrial technology of potato cultivation on growth, yield and quality of products. There was a positive response of plants to fertilizer K2SO4 in the period of planting. Correlation and regression analysis of yield and quality of tubers revealed a high degree of reliability of the results of experience. The contents of nitrates and heavy metals in tubers was below the permissible values.

The impact of urban effluents on the coastal marine environment of Mediterranean islands

1995 ◽  
Vol 32 (9-10) ◽  
pp. 85-94 ◽  
Author(s):  
Michael O. Angelidis
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Marine Environment ◽  
Suspended Particle ◽  
Pollution Source ◽  
Mediterranean Islands ◽  
Coastal Marine Environment ◽  
Coastal Marine ◽  
The Impact ◽  
The City

The impact of the urban effluents of Mytilene (Lesvos island, Greece) on the receiving coastal marine environment, was evaluated by studying the quality of the city effluents (BOD5, COD, SS, heavy metals) and the marine sediments (grain size, organic matter, heavy metals). It was found that the urban effluents of Mytilene contain high organic matter and suspended particle load because of septage discharge into the sewerage network. Furthermore, although the city does not host important industrial activity, its effluents contain appreciable metal load, which is mainly associated with the particulate phase. The city effluents are discharged into the coastal marine environment and their colloidal and particulate matter after flocculation settles to the bottom, where is incorporated into the sediments. Over the years, the accumulation of organic matter and metals into the harbour mud has created a non-point pollution source in the relatively non-polluted coastal marine environment of the island. Copper and Zn were the metals which presented the higher enrichment in the sediments of the inner harbour of Mytilene.

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