Activating of Nickel Slag and Preparing of Cementitious Materials for Backfilling

2014 ◽  
Vol 936 ◽  
pp. 1624-1629 ◽  
Author(s):  
Ke Qing Li ◽  
Yang Yi Zhang ◽  
Peng Zhao ◽  
Lin Feng
Keyword(s):  
Raw Materials ◽  
Chemical Activation ◽  
Cementitious Materials ◽  
Evaluation Standards ◽  
Smelting Operation ◽  
Backfill Materials ◽  
Filling Method ◽  
Cementitious Activity ◽  
Activation Conditions ◽  
Cementing Agent

The back-filling method is distinguished from other mining methods by its higher cost. In order to solve this problem and utilize water-granulated nickel slag as much as possible, nickel slag from flash smelting operation was used to prepare cementitious materials for backfilling. Approaches including mechanical activation and chemical activation were adopted to improve the cementitious activity of the slag. By taking the strength of the backfill materials as the evaluation standards, the hydration activity and cementitious performance of the slag were investigated under different activation conditions, and the mechanism of chemical activation was analyzed. The results shows that cementing agent prepared by using mainly the slag (occupying 85% of the total raw materials) can be used to replace cement and meet the production requirements for backfilling materials.

Comparative Study of Different Activation Treatments for the Preparation of Activated Carbon: A Mini-Review

2017 ◽  
Vol 100 (3) ◽  
pp. 299-312 ◽  
Author(s):  
Muhammad Imran Din ◽  
Sania Ashraf ◽  
Azeem Intisar
Keyword(s):  
Activated Carbon ◽  
Comparative Study ◽  
Raw Materials ◽  
Chemical Activation ◽  
Comparative Approach ◽  
Adsorption Mechanisms ◽  
Temperature Activation ◽  
Activation Conditions ◽  
Physical And Chemical ◽  
Characterisation Techniques

In this review, various methods of preparation of activated carbon from agricultural and commercial waste material are reviewed. In addition, we also discuss various activation treatments using a comparative approach. The data are organised in tabulated form for ease of comparative study. A review of numerous characterisation techniques is also provided. The effect of time and temperature, activation conditions, carbonisation conditions and impregnation ratios are explained and several physical and chemical activation treatments of raw materials and their impact on the micro- and mesoporous volumes and surface area are discussed. Lastly, a review of adsorption mechanisms of activated carbon (AC) is also provided.

scholarly journals An Assessment of Reuse of Light Ash from Bayer Process Fluidized Bed Boilers in Geopolymer Synthesis at Ambient Temperature

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Woshington S. Brito ◽  
André L. Mileo Ferraioli Silva ◽  
Rozineide A. A. Boca Santa ◽  
Kristoff Svensson ◽  
José Antônio da Silva Souza ◽  
...  
Keyword(s):  
Fly Ash ◽  
Ambient Temperature ◽  
Raw Materials ◽  
Chemical Activation ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Bayer Process ◽  
Dimensional Structure ◽  
Aluminum Production ◽  
Production Chain

Sustainable civil construction in the future, besides having low energy consumption and greenhouse gas emissions, must also adopt the principle of reusing wastes generated in the production chain that impact the environment. The aluminum production chain includes refining using the Bayer process. One of the main wastes produced by the Bayer process that has an impact on the environment is fly ash. Geopolymers are cementitious materials with a three-dimensional structure formed by the chemical activation of aluminosilicates. According to studies, some are proving to be appropriate sources of Al and Si in the geopolymerization reaction. The research reported here sought to assess the possibility of reusing fly ash characteristic of the operational temperature and pressure conditions of Bayer process boilers in geopolymer synthesis. Geopolymerization reaction was conducted at an ambient temperature of 30°C, and the activator used was sodium hydroxide (NaOH) 15 molar and sodium silicate (Na2SiO3) alkaline 10 molar. Fly ash and metakaolin were used as sources of Al and Si. XRD, XRF, and SEM Techniques were used for characterizing the raw materials and geopolymers. As a study parameter, the mole ratios utilized followed data from the literature described by Davidovits (year), so that the best results of the geopolymer samples were obtained in the 2.5 to 3.23 range. Resistance to mechanical compression reached 25 MPa in 24 hours of curing and 44 MPa after 28 days of curing at ambient temperature.

Minimizing Segregation in Bunkers

1973 ◽  
Vol 95 (1) ◽  
pp. 81-85 ◽  
Author(s):  
K. Clague ◽  
H. Wright
Keyword(s):  
Particle Size ◽  
Flow Regime ◽  
Mass Flow ◽  
Raw Materials ◽  
Model Tests ◽  
Material Density ◽  
Filling Method ◽  
Density Results

Bunkers used in steelworks sinter plants and other applications need to be designed and operated so that the feed emerging is unsegregated. A series of model tests has been carried out to discover which bunker shape, flow regime, and filling method give the least segregation for raw materials of different particle size and density. Results are compared with results from larger bunkers. The main conclusions are that an evenly-filled wedge-shaped mass-flow bunker is best at preventing segregation and that material density has little effect.

scholarly journals Highly microporous carbons from olive tree pruning: Optimization of chemical activation conditions

2019 ◽  
Vol 7 (1) ◽  
pp. 102830 ◽  
Author(s):  
Arminda Mamaní ◽  
María Fabiana Sardella ◽  
Marianela Giménez ◽  
Cristina Deiana
Keyword(s):  
Chemical Activation ◽  
Olive Tree ◽  
Microporous Carbons ◽  
Activation Conditions ◽  
Tree Pruning

scholarly journals Microporosity Development of Herringbone Carbon Nanofibers by RbOH Chemical Activation

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Vicente Jiménez ◽  
Paula Sánchez ◽  
Fernando Dorado ◽  
José Luís Valverde ◽  
Amaya Romero
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Carbon Nanofibers ◽  
Flow Rate ◽  
Chemical Activation ◽  
Micropore Volume ◽  
Structure Development ◽  
Activation Temperature ◽  
Activating Agent ◽  
Activation Conditions

The influence of different activation conditions, including activating agent/CNFs ratio, activation temperature, and He flow rate, on the pore structure development of herringbone carbon nanofibers (CNFs) was studied. The best results of activated CNFs with larger specific surface area can be achieved using the following optimized factors: RbOH/CNFs ratio = 4/1, activation temperature = ,and a He flow rate = 850 ml/min. The optimization of these three factors leads to high CNFs micropore volume, being the surface area increased by a factor of 3 compared to the raw CNFs. It is important to note that only the creation of micropores (ultramicropores principally) took place, and mesopores were not generated if compared with raw CNFs.

scholarly journals Characterization and Modelling Studies of Activated Carbon Produced from Rubber-Seed Shell Using KOH for CO2 Adsorption

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 855 ◽  
Author(s):  
Azry Borhan ◽  
Suzana Yusup ◽  
Jun Wei Lim ◽  
Pau Loke Show
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Co2 Adsorption ◽  
Chemical Activation ◽  
Freundlich Isotherm ◽  
Nitrogen Adsorption ◽  
Rubber Seed ◽  
Modelling Studies ◽  
Carbon Dioxide Co2 ◽  
Activation Conditions

Global warming due to the emission of carbon dioxide (CO2) has become a serious problem in recent times. Although diverse methods have been offered, adsorption using activated carbon (AC) from agriculture waste is regarded to be the most applicable one due to numerous advantages. In this paper, the preparation of AC from rubber-seed shell (RSS), an agriculture residue through chemical activation using potassium hydroxide (KOH), was investigated. The prepared AC was characterized by nitrogen adsorption–desorption isotherms measured in Micrometrices ASAP 2020 and FESEM. The optimal activation conditions were found at an impregnation ratio of 1:2 and carbonized at a temperature of 700 °C for 120 min. Sample A6 is found to yield the largest surface area of 1129.68 m2/g with a mesoporous pore diameter of 3.46 nm, respectively. Using the static volumetric technique evaluated at 25 °C and 1.25 bar, the maximum CO2 adsorption capacity is 43.509 cm3/g. The experimental data were analyzed using several isotherm and kinetic models. Owing to the closeness of regression coefficient (R2) to unity, the Freundlich isotherm and pseudo-second kinetic model provide the best fit to the experimental data suggesting that the RSS AC prepared is an attractive source for CO2 adsorption applications.

scholarly journals Experimental Study on the Performance and Microstructure of Cementitious Materials Made with Dune Sand

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Chaohua Jiang ◽  
Xiaobin Zhou ◽  
Guilan Tao ◽  
Da Chen
Keyword(s):  
Raw Materials ◽  
Cementitious Materials ◽  
Dune Sand ◽  
Ordinary Concrete ◽  
Granulated Blast Furnace Slag ◽  
The Matrix ◽  
Lower Porosity ◽  
Dry Shrinkage ◽  
Hydrate Products ◽  
Furnace Slag

This paper presents the results of an investigation on the utilization of dune sand from waterway regulation engineering as the main raw materials to produce cementitious materials. The mechanical and durability properties of the cementitious materials were studied. Furthermore, a scanning electron microscope (SEM) and mercury intrusion porosimeter (MIP) were used to identify the microstructure of the specimens. The results show that the compressive and splitting tensile strength of cementitious materials can be improved due to the addition of ground granulated blast-furnace slag (GGBS) which mainly attributes to a better grain size distribution and pozzolanic effect compared to the specimen added cement alone. The specimen with the addition of suitable cement, GGBS, and gypsum shows low dry shrinkage and excellent abrasion resistance. Correspondingly the specimens present a lower porosity and total volume of pores at different curing ages. The SEM observation indicates that there are quite a lot of hydrate products such as calcium silicate hydrate gel in the matrix which verifies the formation of cementitious compounds. The results obtained suggest that there is potential in manufacturing cementitious material with dune sand in substitution of ordinary concrete to use in hydraulic engineering.

scholarly journals The Use of SEM and Other Complimentary Techniques for the Determination of Properties of Cementitious Materials

1992 ◽  
Vol 00 (8) ◽  
pp. 4-4 ◽  
Author(s):  
Eric A. Draper ◽  
Jan Skalny
Keyword(s):  
Building Materials ◽  
State Of The Art ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Modern State ◽  
Microscopic Evaluation ◽  
The World ◽  
Cost Effect

The need for continued rehabilitation of our concrete infrastructure has lead to the adaptation of modern “state-of-the-art” analytical methods for the characterization of concrete and other cementitious materials. Some of these techniques have not, until relatively recently, been commonly associated with the evaluation of concrete but are very useful both as tools for quality assurance and in the determination of the extent of existing damage. The technique of interest here is the coordinated electron-optical microscopic evaluation of concrete.Concrete is the most widely used building material in the world. Contrary to popular belief, concrete is not inert but chemically very complex and dynamic. While it is true that, pound for pound, concrete and its raw materials (cement, aggregate and water} are the most inexpensive building materials available for construction, it is also true that it responds to its environment in numerous and sometimes very subtle ways. These responses may sometimes result in a loss of durability and tremendous amounts of time and money being expended while searching for the cause(s) of the problem and providing a cost-effect solution A quick survey of any large metropolitan area and the on-going construction repairs to highways and bridge decks there will quickly confirm this.

Study on Advanced Treatment of Landfill Leachate by Sludge-Based Activated Carbon

2014 ◽  
Vol 955-959 ◽  
pp. 2701-2704
Author(s):  
You Lan Chen ◽  
Shan Shan Wu
Keyword(s):  
Activated Carbon ◽  
Landfill Leachate ◽  
Pollution Control ◽  
Raw Materials ◽  
Chemical Activation ◽  
Ground Surface ◽  
Domestic Waste ◽  
Vertical Ground ◽  
Characterization Of Activated Carbon

Sludge-based Activated Carbon(SAC) was carried out on the method of chemical activation and high temperature pyrolysis, using municipal sludge as the main raw materials, mixed with a small amount of corn straw. Through the analysis of characterization of activated carbon, the best quality blending ratio of straw is 10% ; the dynamic adsorption results of tail liquid of landfill leachate show that SAC can effectively remove most of harmful substances in the tail liquid of landfill leachate and the effluent reached the vertical ground surface standard of the standard for pollution control on the landfill site for domestic waste .

Impact of Grinding Technology on Final Properties of Portland Cement

2016 ◽  
Vol 677 ◽  
pp. 191-196
Author(s):  
Karel Dvořák ◽  
Dusan Dolak ◽  
Iveta Hájková
Keyword(s):  
Portland Cement ◽  
Raw Materials ◽  
Chemical Activation ◽  
Technical Equipment ◽  
Production Methods ◽  
The Past ◽  
Main Emphasis ◽  
Save Energy ◽  
Burning Mode ◽  
Reducing Energy

Portland cement got his name derived from the appearance of concrete that resembles sandstone located near city of Portland in England. In 1824, John Aspdin was granted a patent for the production of Portland cement.In the past, energy and economic demands on production of cement were lower than they are today. Production was characterized by a slower burning mode and coarser grinding. Product produced this way were reaching lower compressive strength.Currently there are several companies producing Portland cement. Main ones in Czech Republic are Holcim, Heidelbergcement group and Lafarge Cement a.s. Their production methods are very similar. The differences are mostly in the possibility of using local raw materials with different chemical composition and the technical equipment of factories. In the production, the main emphasis is on reducing energy and financial cost.One way to save energy and money is to use mechanical-chemical activation when grinding Portland clinker.

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