2020年7月1日· Fuerstenau [3] examined the effect of aluminium chloride on grinding efficiency of quartz at different pH conditions where improvement was only materialized in the acidic to neutral conditions Water was also considered as a GA to explain the better2021年11月11日· The amount of bound chloride per gram of dry cement paste as a function of the chloride concentration of the added NaCl or CaCl 2 solution The legendChloride binding in concrete: recent investigations and
2017年10月29日· This paper reports on the advantages and drawbacks of available test methods for the determination of chloride content in cementitious materials in general,2015年3月2日· The role of chloride in cement has had a mixed history On the one hand, chloride has long been used to accelerate cement hydration and strength gain On theChloride in cement | Advances in Cement Research
2014年10月15日· The results indicate that the chemicals whether pure grinding aid or mixed product have an improved effect on circuit production rate Certainly, the target1 天前· Methods for obtaining dust samples by means of grinding concrete in order to determine the chloride concentration profile Mater Struct 2013, 46, 337–344 [GoogleApplied Sciences | Free FullText | Effect of a Crystalline Admixture
2022年9月19日· The polycarboxylate grinding aid has both good grinding aid and efficient water reducing properties, delaying the accelerated period of cement hydration and2023年6月1日· Up to now, the effect of chloride ions on the hydration process of cement, especially early hydration, is not thoroughly understood The hydration of cementbasedEffects of chloride content on early hydration performance of
2018年9月24日· Testing methods Equilibrium method for chloride binding The chloride binding capacity of hydrated cement pastes was characterized using the equilibriumGrinding aids, first introduced into cement manufacturing in 1930 [1], are surfaceactive substances that facilitate particle comminution during the milling process In theThe Effect of Various Grinding Aids on the Properties of Cement
2015年6月10日· Abstract and Figures In this paper, the effect of FeSO47H2O and SnCl22H2O on Cr (VI) reduction is compared by measuring Cr (VI) content before and after adding of reducing additives2018年3月19日· Milling aids have been predominantly developed to increase the performance or grinding capacity of cement products, and alcohol amines have been used as grinding aids in cement grinding processes for many years Moreover, the setting point of cement produced with grinding aids is most often changed In this study, the effectsUse of Boron Compounds as Grinding Aids with Alcohol
2023年11月20日· To improve the efficiency and stability of chloride immobilization of portland cement paste, hydrated calcium aluminate cement (HCAC) prepared by wet grinding of CAC was added into portland cement paste as an additive The immobilized chloride ratio (ICR) was evaluated, and the mechanism of chloride immobilization was2020年4月1日· Before being able to calculate the effect of HCl on the chloride binding in cement paste, the question of paste dissolution and solution volume increase must be solved Using the calculated volume increases in Fig 17 , three different levels of chloride binding can be found for the HClsamples: One for each density (2 and 3 g/mL), plus oneThe effect of artificial leaching with HCl on chloride binding in
Chromium (VI) Reducing Agents The raw materials for grey Portland cement manufacturing may contain chromium Due to the highly oxidizing and alkaline conditions of the kiln, during clinker production chromium is partially converted to hexavalent chromium As a result, Portland clinkers and cements contain soluble chromates (usually in theHealth effects Cement can cause ill health by skin contact, eye contact, or inhalation Risk of injury depends on duration and level of exposure and individual sensitivity Hazardous materials in wet concrete and mortar include: alkaline compounds such as lime (calcium oxide) that are corrosive to human tissueCement Hazards and Controls Health Risks and Precautions in
Hexavalent Chromium in Cement Manufacturing: magnesiachrome kiln refractory brick, if used, 3) wear metal from raw mill grinding process, if chromium alloys are used, and 4) additions such as gypsum manganese sulfate, and stannous chloride Some of these materials have limitations such as limited stability, limited supply, and2015年3月2日· Portland cement–steel composites frequently take up chloride from their service environment The degradation processes and test methods are described through a critical review of the literature Plain cement paste is not much affected by chloride except for increased solubilisation of cement solids, but chloride is detrimental to theChloride in cement | Advances in Cement Research
Additionally, the reaction degree of cement without TIPA is 6811%, while that for addition of TIPA (006%), it is 7431%, which indicates the accelerated hydration of cement by TIPA The same results can also be found in FA: the reaction degree of FA is increased from 3618% to 4198% with 006% TIPA2022年9月19日· In view of the disadvantages of polycarboxylic acid grinding aids, such as poor reinforcement effect and cumbersome synthesis process, a new type of polycarboxylic acid grinding aid was prepared to meet the requirements of multifunctional admixture for cement concrete The polycarboxylate grinding aid (PC) was prepared using acrylicEffect of Polycarboxylic Grinding Aid on Cement Chemistry and
2015年10月23日· In this chapter an introduction of widely applied energyefficient grinding technologies in cement grinding and description of the operating principles of the related equipments and comparisons over2022年4月15日· Due to the toxicity and mobility of chromium, the disposal of chromiumcontaining waste is a pressing issue Coprocessing of chromiumcontaining waste in a cement kiln is currently one of the mostEffects of Alkali on Water Soluble Hexavalent
2023年7月15日· Carbonation curing of concrete is an effective measure to reduce CO 2 emissions, but it can adversely affect chloride binding capacity of cement pastes and its durability In this study, the chloride ion content and phase assemblages of cement pastes under three curing conditions: standard curing, carbonation curing, and mixed curing (72017年6月15日· Triethanolamine (TEA) is the main chemical used as cement additive with multi functions as grinding aid during cement comminution process and setting time regulator for cement hydrations This couple function is the main advantage from using TEA in addition to the relatively small dosage as well as the alkali and chloride free featuresEffect of triethanolamine on cement hydration toward initial setting
Since Directive 2003/53/EC came into effect, all EU Member States have been obliged since 17 January 2005 to reduce the chromate content in cement and cementcontaining preparations Among other things, Regulation (EC) No 1907/2006 defines the following restriction regarding the production, marketing and use of cement and cementcontaining2020年7月1日· 1 Introduction The term chemical additives or grinding aids (GAs) refers to any substance which results in increased grinding efficiency and reduction in power consumption when added to the mill charge (amounts not exceeding 025 wt% of the feed) during grinding [1], [2], [3]The use of grinding aids to increase mill throughput is quiteA critical review on the mechanisms of chemical additives used in
2023年12月8日· In this study, barium ions (Ba 2+) were loaded in expanded perlite (EP) to prepare Ba/EP composites and then added to the Portland cement paste The chloride ion binding capacity and the setting time of the cementBa/EP composite system were verified The diffusion of Ba 2+ in the cement paste was observed by SEMEDS, and the phase2014年7月23日· The calorimetric measurements were applied in testing the effect of some sulfates, used as Cr(VI) reducers in cement, as setting and hardening modifiers The iron(II) sulfate is most commonly added as Cr reducer to cement on grinding This was taken as a reference in the studies of the other potential chromium reducers, such as tin(II) andThe studies of the effect of sulfates added as chromium(VI
Chromium(VI) levels in cement produced is Lukavac is up to 8 ppm, with the majority between 5 and 7 ppm Chromate has high oxidizing effectiveness, because of its high ambition to switch over to the level of the trivalent Cr by addition of oxidizable substances as ferrous sulfate, stannous sulfate or antimony(III) compounds2014年11月1日· The effect of magnesium and sulphate present in sea water on chloride binding in Portland cement paste was investigated Ground well hydrated cement paste was exposed to MgCl 2, NaCl, NaCl + MgCl 2, MgSO 4 + MgCl 2 and artificial sea water solutions with a range of concentrations at 20 °C Chloride binding isotherms areThe impact of sulphate and magnesium on chloride binding in Portland
1994年6月1日· Klemm, WA Construction Technology Laboratories, Inc, Skokie, IL Due to increasing environmental and healthrelated concerns, the amount of hexavalent chromium found in portland cement is coming under increasing scrutiny Hexavalent chromium has been classified as a carcinogen, and its release into the air or groundwat2011年9月1日· In this paper, the effect of FeSO47H2O and SnCl22H2O on Cr(VI) reduction is compared by measuring Cr(VI) content before and after adding of reducing additives in cement samples(PDF) EFFECT OF RAW MATERIALS AND REDUCTION
2023年3月18日· To combat environmental challenges—such as the depletion of natural resources and a high carbon footprint—and contribute to the effort of achieving zerowaste technology and sustainable2014年10月1日· The Xray diffraction patterns of the cement pastes cured in the presence of tin(II) chloride showed several additional peaks that have been attributed to the formation of calcium hydroxostannate(PDF) The studies of the effect of sulfates added as chromium(VI
2016年10月30日· Isothermal calorimetry study of the effect of chloride accelerators on the hydration kinetics of oil well cement Constr Build Mater, 77 (2015), pp 260269 Characterization of various cement grinding aids and their impact on grindability and cement performance Constr Build Mater, 23 (2009)2011年12月1日· The order of chloridebinding capacity as a function of exposure temperature is as follows: 22°C>3°C>13°C>5°C The order of chloridebinding capacity as a function of the percentage of GGBFSEffect of Cold Temperature on the ChlorideBinding Capacity of Cement
2011年6月24日· This paper examines the effect of temperature ranging from 22°C to –3°C on the chloridebinding capacity for cement paste containing varying percentages of “Effect of cement type on chloride binding and corrosion of steel in concrete” Cem Concr Res, 25(4), 893–902 Crossref Google Scholar Bertolini, L (2008White dealing with the durability aspect of concrete, the chloride effect on concrete is the most important factor as it causes the corrosion of reinforcement of concrete The statistical studies have shown that more than 40% structures have failed due to the corrosion of reinforcement steel Due to high alkaline nature of calcium hydroxideEffect of Chloride Attack on Durability of Concrete | Concrete Technology
2020年7月15日· The spherical RFA balls in Fig 1 a were observed, and then they were destroyed and grinded into small particles in Fig 1 b It was noticed that a small amount of hydrates revealed that a little hydration took place during the wet grinding process, as it might be seen in Fig 1 b (Yang et al, 2019c)The fineness of RFA and UFA wasThe comparative analysis was carried out to know the effect of chromium hexavalent reducing additives such as ferrous sulphate (FeSO 47H 2 O) and stannous chloride SnCl 22H 2 O on the reduction of Cr (VI) by measurement of Cr(VI) before and after adding the reducing agent in cement samplesEffect of FeSO47H2O and SnCl22H2O added as Chromium (VI)
En exemplary method for reducing hexavalent chromium in cementious compositions comprises: combining a cement and a reducing agent selected from the group consisting of (A) a hydroxylamine or the salt or derivative thereof, the hydroxylamine having a structure represented by the formula wherein R 1 and R 2 each comprise a hydrogen or C 1 C 年12月1日· As a common grinding aid in cement mills, alkanolamine can significantly reduce the energy consumption and enhance cement property When alkanolamine is used as a cement chemical additive, it will change the hydration characteristics of the cement bonds and hardening properties However, the effect of alkanolamine on the hydration ofAdvances of alkanolamine in hydration of Portland cement
2020年7月15日· In this study, to promote the chloride binding capacity of coal fired fly ash (RFA) in cementitious materials, wet grinding was employed and ultrafine fly ash (UFA) with D50 = 21 μm was prepared; SEM, XRD, TG, FTIR, and XPS were used to evaluate the chemical and physical change in the process of wet grindingThen, two kinds of binders2018年9月1日· Mangi et al [1] investigated the effects of sodium and chloride attack on concrete blended with coal bottom ashes for the exposure period of 90 days, and it was found that incorporation of coal(PDF) Shortterm effects of sulphate and chloride on the concrete
2012年1月1日· TEA, conventionally used as a grinding aid for cement clinker as well as an accelerator to compensate for the retarding effect of some superplasticizers [25], might also be used as a setting2021年4月1日· Calcium stearate combines with cement and water to generate a waxlike substance with a weaker bond than the CSH compound Further it was observed that utilising hydrophobic chemicals such asEffect of hydrophobic agent in cement and concrete : A Review
Phosphate ester polymers were prepared from phosphate ester monomers for the first time and their effects as cement grinding aids and waterreducing performance were studied Fouriertransform infrared (FTIR) spectroscopy and tests for standard viscosity, setting time, mortar fluidity, mortar compressive strength were conducted The results showed that2018年2月21日· Why, When, and How Corrosion Happens Concrete is a porous material with a pore solution that typically maintains a pH higher than 126 Under these alkaline conditions, a thin (nanometer scale) “passive” film forms on the reinforcement surface which effectively stops corrosion This passive film breaks down due to the exposure toPredicting Concrete Corrosion: The Effects of Chloride | Giatec
This paper presents the results of a study conducted to assess the effect of sulphate contamination on the chloridebinding capacity of plain and blended cements Cement paste specimens admixed with a fixed quantity of sodium chloride and varying dosages of sodium sulphate or magnesium sulphate were prepared The pore solution was extractedWater Spray in Cement Mills Water spray installed generally in second compartment of ball mill to control cement temperature Cement discharge temperature should be kept below about 110 o C but, the same time should allow some 60% dehydration of gypsum to optimize cement strength without excessive false setCement Grinding Cement Plant Optimization
