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1.
研究了废白土做填充剂及软化剂在天然橡胶中的应用,并与同份数的陶土(同时添加3份芳烃油)进行性能对比。结果表明:废白土可以作为填充剂和软化剂应用于天然橡胶中,且以废白土为填料的胶料流动性、焦烧性、扯断永久变形性能好、耐磨耗性能、冲击弹性、伸长率、耐老化性能均好。  相似文献   

2.
The precipitation characteristics of palladium (Pd) from a simulated radwaste solution by ascorbic acid was investigated. Pd was selectively precipitated by the reduction reaction of Pd with ascorbic acid. When the nitric acid concentration in the 8 component system was below 2.0 M, Pd over 99.5 % was selectively precipitated at an ascorbic acid concentration above 0.06 M, while other elements mainly remained in solution. The precipitation yield of Pd by ascorbic acid decreased with the increase of the nitric acid concentration.  相似文献   

3.
Cementitious ceramics, produced from the hydration of cement and hydrated lime, are responsible for a great deal of damage to the environment due to the high emission of CO2 that occurs in the production of cement and lime. Therefore, the objective of this work was to substitute the hydrated lime with a combination of clay residue and marble waste extracted from ceramic and ornamental rock producing industries, respectively, which constitutes a circular economy for the ceramic industry related to masonry applications. Ceramics were produced in the proportion 1:1:6:1.5 (cement:lime:sand:water), through the molding procedure, and were studied by replacing hydrated lime with 100% clay residue and 100% marble residue, in addition to stoichiometric calculated parts of marble to clay. The molar ratios used were 1:1, 1:2, and 2:1 (marble:clay). Tests of consistency, incorporated air content, water retention, compression strength, density, water absorption by capillarity, adhesion, and electrical resistivity were performed. The results obtained demonstrate that the use of residue of marble and clay together, as long as they are correctly balanced, provides a high gain in technological properties, enabling the circular economy of cementitious ceramics, mainly for the composition 1 marble:1clay, which presented the best properties, both in the fresh and hardened state. The economic analysis carried out proved the financial gains for the industrial sectors involved (civil construction, ornamental rock, and ceramic).  相似文献   

4.
工业废料加固土的试验研究   总被引:2,自引:0,他引:2  
利用炉渣和粉煤灰等废渣、并掺入适量水泥或石灰等胶凝剂来加固土壤,可以节约工程造价、改善环境。分别以水泥、石灰、水泥 石灰混合料加固由粉煤灰、粘土、细砂、淤泥.炉渣以不同配比组成的三种复合土,每种拌合物以相同的加水量分别制备3组试件.自然条件下养护3d.7d.28d后进行无侧限压强度试验、结果表明:A型复合土单掺水泥的加固效果最为显著,其早期和28d强度值均随水泥掺量的增加而显著提高;c型土则单掺石灰的效果最好.最佳掺量为15%;等量复掺“水泥 石灰”时.对B型土的加固效果最好,这说明掺入一定的水泥或石灰或同时加入水泥和石灰加固由粉煤灰,炉渣、软粘土、淤泥和细砂组成的复合土在技术上是可行的.  相似文献   

5.
Bentonites have been proposed as buffer material for barriers in geological disposal facilities for radioactive waste. This material is expected to fill up by swelling the void between the canisters containing the waste and the surrounding ground. However, the bentonite barriers may be submitted to changes of humidity, temperature variation, fluid interaction, mass transport, etc. This could modify the physico-chemical performance of the barrier, mainly on the interface with the steel container and with the geological barrier. The engineered barrier development necessitates thus the study of the physico-chemical stability of its mineral component as a function of time under the conditions of the repository in the long-term.The purpose of the present study was two-fold. Firstly, it was hoped to simulate the chemical transformations (geochemical and cation exchange reactions) coupled with diffusion of chemical-elements into the engineered barrier under repository conditions by applying a thermokinetic hydrochemical code (KIRMAT: Kinetic Reactions and Mass transport).Secondly, it was hoped to apply a simplified method to estimate the swelling capacity evolution by a volume balance in the fluid-saturated engineered barrier, considering that the decay of swelling capacity is directly proportional on the volume of transformed montmorillonite and, taking into account that it may be partially compensated by the volume of neo-formed swelling clays.The system modelled herein was considered to consist of 1-m thick zone of water-saturated engineered barrier. This non-equilibrated system was placed in contact with a geological fluid on one side, which was then allowed to diffuse into the barrier, while the other side was kept in contact with a source of metallic iron. Reducing initial conditions(PO2 0; Eh = − 200 mV) and a constant reaction temperature (100 °C) were considered.The results showed that the EB in contact with the geological fluid was highly transformed after 10,000 years, whereas the most significant chemical processes were illitization, cation exchange and saponization, extending up to 20 cm into the EB. Chemical transformations of minor importance in the EB were identified as well, such as a neo-formation of silicates (quartz, cristobalite), anhydrite, laumontite, magnetite and chlorite in the system.A simplified method based on volume balance showed that the swelling capacity of the bentonite barrier is slightly affected after 10,000 years of diffusion–reaction (D close to 1) because the volume of neo-formed swelling-clays is almost directly proportional to the volume of transformed Na/Ca-montmorillonite, except for a strong illitization and/or neo-formation of non-swelling clays. In the present study, this simple approach predicted that the decay of swelling capacity of the engineered barrier is drastically affected close to the geological barrier-engineered barrier interface. Out this zone the swelling capacity decay lies between 5% and 11%.  相似文献   

6.
Composite fabricated from starch and different concentrations of clay was prepared by solution casting method. The casted film was irradiated to different gamma irradiation doses 10, 20, 30, and 40 kGy. The dispersion of clay into starch was investigated by using X‐ray diffraction (XRD). The structural morphology of the composite was measured by scanning electron microscope and infrared spectroscopy. Film properties, such as water vapor transmission, mechanical, and thermal properties were also measured. The gel content and swelling behavior of the starch/clay composite were investigated. It was found that the gel content increases with increasing clay content and irradiation dose. The results obtained indicate that the starch/clay composite showed an increase in the tensile strength, thermal stability. Moreover, there is a decrease in water vapor transmission (WVRT) which improves its barrier properties. Both XRD and infrared spectroscopy showed that starch can be intercalated into the clay galleries. Also antibiotic drug Chlortetracycline HCl was loaded into the starch/clay composite by direct adsorption method. Chlortetracycline HCl adsorption capacity of composite was found to increase from 1.13 to 4.20 mg Chlortetracycline HCl per gram dry film with increasing amount of drug concentration. In vitro drug release studies in different buffer solutions showed that the basic parameters affecting the drug release behavior of the film are pH of the solution, drug concentration, and time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

7.
In this work an extensive SEM/EDS microstructural investigation associated with technological properties was carried out on kaolinitic clay bodies incorporating different amounts, up to 20 wt.%, of a bentonite-treated petroleum waste. The clay bodies were fired at temperatures from 850 to 1100 °C and then bend tested until rupture. Fracture surface observation revealed the existence of relatively small BaSO4 particles that do not significantly contribute to the rupture process. By contrast, larger clay matrix embedded particles and voids exert more influence on the ceramic rupture. Since these particles are also normal features in waste-free clay bodies, the incorporation of bentonite-treated petroleum waste cannot be directly related to the rupture process. Exception occurred above 10 wt.% added waste and temperatures higher than 1000 °C, at which the comparatively higher amount of non-plastic quartz particles plays a role in the decrease of strength.  相似文献   

8.
Investigations were carried out in order to solidify in cement a low-level radioactive waste of complex chemistry obtained by mixing two process streams, a slurry produced by ultra-filtration and an evaporator concentrate with a salinity of 600 gxL− 1. Direct cementation with Portland cement (OPC) was not possible due to a very long setting time of cement resulting from borates and phosphates contained in the waste. According to a classical approach, this difficulty could be solved by pre-treating the waste to reduce adverse cement–waste interactions. A two-stage process was defined, including precipitation of phosphates and sulfates at 60 °C by adding calcium and barium hydroxide to the waste stream, and encapsulation with a blend of OPC and calcium aluminate cement (CAC) to convert borates into calcium quadriboroaluminate. The material obtained with a 30% waste loading complied with specifications. However, the pre-treatment step made the process complex and costly. A new alternative was then developed: the direct encapsulation of the waste with a blend of OPC and calcium sulfoaluminate cement (CS̄̄A) at room temperature. Setting inhibition was suppressed, which probably resulted from the fact that, when hydrating, CS̄̄A cement formed significant amounts of ettringite and calcium monosulfoaluminate hydrate which incorporated borates into their structure. As a consequence, the waste loading could be increased to 56% while keeping acceptable properties at the laboratory scale.  相似文献   

9.
In this study, it was aimed to stabilize trommel sieve waste (TSW) occurring during manufacture of borax from tincal. The effects of TSW added on the mechanical properties and radioactive transmission of modified cement prepared by adding TSW to clinker was investigated. The properties which TSW as additive caused the cement to gain were tested and compared with normal Portland cement.Measurements have been made to determine variation of mass attenuation coefficients of TSW and cement by using an extremely narrow-collimated-beam transmission method in the energy range 15.746-40.930 keV with X-ray transmission method. The characteristic Kα and Kβ X-rays of the different elements (Zr, Mo, Ag, In, Sb, Ba and Pr) passed through TSW and cement were detected with a high-resolution Si(Li) detector. Results are presented and discussed in this paper.  相似文献   

10.
The objective of this experimental study was to use ground clay brick (GCB) as a pozzolanic material to minimize the alkali-silica reaction expansion. Two different types of clay bricks were finely ground and their activity indices were determined. ASTM accelerated mortar bar tests were performed to investigate the effect of GCB when used to replace cement mass. The microstructure of the mortar was investigated using scanning electron microscopy (SEM). The results showed that the GCBs meet the strength activity requirements of ASTM. In addition, the GCBs were found to be effective in suppressing the alkali-silica reaction expansion. The expansion decreased as the amount of GCBs in the mortar increased.  相似文献   

11.
Since K fixation in soils is largely a function of clay mineralogy, an effort was made to elucidate the influence of mineralogical variations in soil clays on K fixation, under the moisture-temperature regimes usually prevalent in tropical upland rice soils. Beidellitic clay turned out to be the most severe fixer of addedK (80%), followed by vermiculitic (69%) clays. Fixation is not appreciable (< 15%) in clays consisting of montmorillonite, x-ray amorphous material, chlorite, hydrous mica, kaolinite and halloysite. Fixation by beidellite and vermiculite clays is reduced by the simultaneous occurrence of other mineral species.  相似文献   

12.
Water and nutrients are two important inputs to agriculture that need to be used judiciously with higher efficiency to save these limited resources. For these purposes, a series of nanoclay–polymer composite (NCPC) superabsorbent nutrient carriers were prepared. These NCPCs were based on the reactions of different types of nanoclays (10 wt %) with partially neutralized acrylic acid and acryl amide by a free‐radical aqueous solution copolymerization reaction with N,N′‐methylene bisacrylamide as a crosslinker and ammonium persulfate as an initiator. The nanoclays isolated from three different types of soils were dominant in kaolinite (clay I ), mica (clay II ), and montmorillonite (clay III ), and a portion of each was freed from amorphous aluminosilicate. Thus, there were six different types of nanoclays used, namely, those dominated by kaolinite, mica, and smectite with and without amorphous aluminosilicate. Fourier transform infrared spectroscopy and X‐ray diffraction (XRD) investigations showed evidence of interaction between the clays and polymer. XRD investigation also showed that the reaction between the polymer and clays I and II occurred on the surface of various clay particles without intercalating into the stacked silicate galleries, whereas in the case of clay III (the smectite‐dominated clay), evidence indicated the intercalation of polymer into the stacked silicate galleries of the clay and the exfoliation of the clay. The water absorbency decreased in the NCPCs compared to that of the pure polymeric hydrogel. In case of the pure polymer, the entire amount of nutrient loading released within 15 h of incubation; this was higher than that of the NCPCs. In the initial stage (up to 15 h), no significant differences in nutrient release were observed among the different polymer/clay composites, but there were differences in later stages. Among the different NCPCs, the percentage release of nutrients at 48 h ranged from around 70% in the polymer/clay III composite to 90% in the polymer/clay I composite. The presence of amorphous aluminosilicates in clay did not make any difference in the nutrient‐release rate. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39951.  相似文献   

13.
Nanocomposites based on a furan resin and different types of clays were obtained. Their thermal and fire behaviours were compared with traditional phenolic resins, which are known by their excellent flame resistance. Three types of montmorillonite clays were in situ added to the thermosetting matrix. A cone calorimeter and a smoke chamber were used to evaluate the performance of the materials against fire and their smokes generation. Global parameters were calculated for comparison purposes. Fires derived from the furan resin combustion grow faster than the phenolic ones, but they are extinguished more rapidly. This effect is enhanced by the incorporation of inorganic nanofillers. The only addition of any clay causes shorter fires but slightly speeds up the degradation process. A homogeneous nanofiller dispersion was found to be crucial to achieve good fire behaviour. Nevertheless, for materials with similar dispersion, the crosslinking degree of the polymer matrix appears as a secondary factor that determines slighter differences in the performance. Nanocomposites with organomodified clays showed a quite similar fire performance, though the composite containing the clay (Southern Clay Products, Inc., Louisville, Ky, USA) Cloisite®30B showed the best performance taking into account both the fire risk and the smoke evolution and obscuration. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

14.
Biomass is an often abundant, renewable, low ash and low sulfur fuel. Due to these properties, biofuels are promising alternatives for traditional petroleum-based fuel applications; however, traditional biofuels for internal combustion engines are not cost competitive with gasoline, diesel or fuel oils. One method to reduce the cost of biofuels is to use slurry fuels which have a potential lower cost than liquid biofuels due to high conversion efficiencies. Slurry biofuels, such as a mixture of corn and water, could provide a biofuel alternative for diesel engines, pressurized gasifiers and heating oil applications such as burners or gas turbines. Use of these biomass slurries poses important questions about their stability and suitability for practical applications in internal combustion engines and combustors.This work reports rheology data for stable corn-starch water slurries (CSWS) which used a polyacrylic acid thickener to eliminate settling of the slurry and to provide desirable shear-thinning behavior for most of the compositions evaluated. The effect of shear rate on the viscosity of the CSWS was studied using a BOHLIN-controlled stress (CS) rheometer. The well-known Ostwald—de Waele power law and Sisko models for viscosity fit the data. The effect of corn starch content, thickener content and temperature on the viscosity of CSWS was also studied. The favorable shear thinning properties were observed for starch contents up to 45% starch and should aid pumping, injection and spraying. The lower heating values of the slurries, however, are undesirably low.  相似文献   

15.
进行了垃圾作水泥生产原料或燃料的分类,着重分析了水泥窑煅烧垃圾生产水泥时,有害排放物CO2,CO,SO2,NOx,重金属,HCl,二恶英和氟的产生过程和控制策略,在此基础上,推荐了一种烟气净化工艺流程,即采用向急冷塔中高压喷射碱液,并辅以袋式除尘器的方法不仅能避免二恶英的后期合成,还可有效降低烟气中SO2,HCl,F的含量。  相似文献   

16.
The activated‐monomer cationic ring‐opening polymerization of ethylene oxide, initiated with ethylene glycol and using an acid‐exchanged montmorillonite clay called Maghnite‐H+ as an effective catalyst, was carried out to obtain the corresponding homopolymers with narrow polydispersity ratios. The molecular weights of the obtained polymers were controlled with the feed ratio of the monomer to the initiator. The effects of the amount of the catalyst and time on the polymerization yield and viscosity of the polymers were studied. The structure was confirmed with proton nuclear magnetic resonance and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

17.
Waste rubber powder (RP) was subjected to chemical modification by using different concentrations of oxidizing agents such as nitric acid and 30% hydrogen peroxide solution. This treatment leads to introducing some functional groups onto the surface of RP. The chemically modified RP was incorporated in natural rubber mixes either alone or in combination with carbon black (HAF). The physicomechanical properties of NR vulcanizates obtained were studied and compared to NR vulcanizates filled with untreated RP. It was found that the chemically modified RP improves tensile strength and aging resistance of NR vulcanizates compared with untreated RP. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 30–36, 2004  相似文献   

18.
使用扫描电子显微镜、X射线荧光光谱仪、激光粒度分析仪等分析手段,对流化床垃圾焚烧炉对流受热面的松散性浮灰和烧结性积灰的微观结构和组成成分等进行研究。结果表明,省煤器浮灰中大部分颗粒保持着独立的形态,而对流管束浮灰存在烧结现象;绝大部分的浮灰粒径位于0~100μm;省煤器浮灰的灰熔点低于对流管束浮灰熔点80℃左右;对流管束浮灰和省煤器浮灰在成分组成上差别不大,浮灰中的主要元素均为Ca、Si、Al和S,但对流管束浮灰中Ca和S的含量高于省煤器浮灰。各层积灰中Ca和S的含量较高,主要物相为CaSO4。对流管束积灰中Ca和S含量高于省煤器积灰;对流管束和省煤器积灰中Al和Si的含量远低于浮灰中的相应含量。从积灰内层到外层Ca和S的含量逐渐减少,而Al和Si的含量逐渐增加;积灰内层K、Na、Fe和Cl的含量高于其他层。  相似文献   

19.
Leather industries which promote hide stabilization by the conventional chrome-tanning process are a major source of pollution because of the resultant chromium-rich wastes. In this work, an extensive characterization of such a chromium-rich waste sludge is presented, regarding its chemical composition (XRF), crystalline phase contents (XRD), organic carbon content (TOC), thermal behavior by thermogravimetry (TG) and differential scanning calorimetry (DSC), as well as its stability under chemical attack (the concentration of important ions in the leachates being determined by capillary electrophoresis) and when submitted to temperatures as high as 1100 °C, in air. The material showed the tendency to produce some undesirable, and previously non-detected hexavalent chromium when exposed to high temperatures, but after washing off the soluble salts and the elimination of the organic matter by firing, the resultant material was succesfully tested as a ceramic pigment in a conventional glaze composition usually employed in the ceramic tile industry.  相似文献   

20.
陈勇 《聚氯乙烯》2012,(2):43-44
介绍了空气压缩系统的运行和耗能情况,针对其中存在的节能空间进行了改造,分析了压缩机的余热利用产生的经济效益。  相似文献   

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