Results 1 - 10 of 1913
Results 1 - 10 of 1913. Search took: 0.024 seconds
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[en] The present paper addresses the alkali activation of Portland cements containing blast furnace slag (20 and 30% by cement weight) with a view to the possible use of these materials in oil well construction. The hydration studies conducted showed that in cement/slag blends, the sodium silicate activator partially inhibited the dissolution of the silicate phases in the Portland cement, retarding cement hydration and reducing the precipitation of reaction products. Due to such partial inhibition, the cement/slag blends had significantly lower mechanical strength than Portland cements hydrated with water. 29Si and 27Al MAS NMR and BSE/EDX studies, in turn, showed that the CSH gel forming in the alkali-activated cement/slag pastes contained Al in tetrahedral positions and low Ca/Si ratios. (Author) 29 refs.
[en] Several tests were performed to provide preliminary data to assess the qualifications of a simulated slagging-pyrolysis incinerated (SPI) transuranic waste form as a DOT proposed Low-Level Solid. The tests were performed to address: (1) the response of a simulated SPI-processed transuranic waste form to realistic process handling and transportation accident scenarios, and (2) the quantity of particulate production of the SPI processed simulated waste form subjected to Type A packaging test conditions as specified in the Code of Federal Regulations, Title 49, Part 173.398. Test results indicate that the simulated SPI waste form and packaging are capable of satisfying the Type A test conditions specified for the new proposed LLS category
[en] A method for decontamination of steel components contaminated with radioactive material comprises melting a mass of material, including a proportion of contaminated steel and slag forming material, to form a volume of molten steel and a volume of slag. The radioactive material originally present in the steel migrates to the slag which is then separated from the steel. The amount of slag forming material utilised may be selected such that the radioactivity of the resulting slag is sufficiently low to permit unrestricted handling and disposal of the slag. (author)
[en] The viscosity of the lands represents one of the most relevant variables of most of the processes metallurgical and kinetics of the refine operations, since it is one of the decisive factors of the efficiency in the reactions between metal and lag, as much as slag-refractory. In the last decades, the mathematical models of different metallurgical processes have established methods to predict viscosity of mixtures of oxides fused to high temperatures in function of the chemical composition. The model developed by Toguri, based on the data reported by Johasen and Winterhager et al has proposed the Kv model. The used index it is similar to the relationship used in the steel industry like the basicity index. It is presented in this work values determined of viscosity in experimental form by means of the technique of inclined plane. (Author)
[en] Process for reprocessing magnesium elements, radioactivated, used or recovered as waste in nuclear reactors whereby, after crushing to fine particles, these elements are mixed with a silico-aluminous substance in the presence of a mineral oxidizer then placed in an electric oven and raised to a temperature of 1400 to 16000C to oxidize the magnesium and cause it to enter into the composition of a synthetic slag, the molten mass then being poured into moulds that are stored in containers forming a barrier to radiation
[fr]Procede de traitement des elements en magnesium, rendus radioactifs, mis en oeuvre ou recuperes comme dechets dans les reacteurs nucleaires, caracterise en ce que, apres broyage sous forme pulverulente, ces elements sont melanges a un materiau silicoalumineux en presence d'un oxydant mineral puis portes au four electrique progressiveement jusqu'a temperature de 1400 a 16000C pour oxyder le magnesium et le faire entrer dans la composition d'un laitier synthetique, la masse fondue etant ensuite coulee dans des moules qui sont stockes dans des conteneurs constituant une barriere pour les radiations
[en] This book mentions structural analysis which deals with definition of structural analysis, and classification of structure, reaction, shear force and bending moment, plane truss, influence line and moving load, arch and cable, column, space truss, a statically indeterminate structure and its approximation solution, slag of structure using geometric method, slag of structure using energy method, slope deflection method, moment distribution method, influence line of a statically indeterminate structure, force method and direct strength method.
[en] The objective of this study is to present an efficient condition for recovering vanadium values from the fuel oil ash. It was found that the ash processing should be conducted on wet grinding, particle size test and leaching test for the maximum vanadium recovery from the fuel oil ash. In leaching test, 90% of elemental vanadium was recovered from the fuel oil ash at leaching temp. of 950C leaching time of 60 min., pH. 2 and pulp density of 50%. (author)
[en] Purpose: To improve the transfer efficiency of radioactive materials into slags. Method: Contaminated metals are melt with adding slagging agent in order to transfer the radioactive materials into the slag, where the slagging agent holds less free energy than that of metal oxides contaminated with radioactive materials in order to promote the transfer of the contaminated materials into the slag layer. This effect can also be attained on metals or alloys other than iron contaminated with radioactive materials. In the case of alloy, the slagging agent is to containing such metal oxide that free energy is less than that of the oxide of metal being the main ingredient element of the alloy. The decontamination effect can further be improved by containing halogenide such as calcium fluoride together with the metal oxide into the slagging agent. (Ikeda, J.)
[en] The antifouling properties for some mortars with steel making slags were investigated by real marine immersion tests and a unique laboratory acceleration tests with a specially devised biofilm acceleration reactors. Mortars mixed with steel making slags containing abundant iron elements tended to form biofilm and also bifouling. The two kinds of biofilm formation tests were used in this study. Real immersion in marine environments and laboratory test with a specially devised biofilm acceleration reactor. The former evaluated the biofouling characteristics more properly, while the latter did the biofilm formation characteristics more effectively
[en] A method for determining the original mix composition of hardened slag-blended cement-based materials based on analysis of backscattered electron images combined with loss on ignition measurements is presented. The method does not require comparison to reference standards or prior knowledge of the composition of the binders used. Therefore, it is well-suited for application to real structures. The method is also able to calculate the degrees of reaction of slag and cement. Results obtained from an experimental study involving sixty samples with a wide range of water/binder (w/b) ratios (0.30 to 0.50), slag/binder ratios (0 to 0.6) and curing ages (3 days to 1 year) show that the method is very promising. The mean absolute errors for the estimated slag, water and cement contents (kg/m3), w/b and s/b ratios were 9.1%, 1.5%, 2.5%, 4.7% and 8.7%, respectively. 91% of the estimated w/b ratios were within 0.036 of the actual values. -- Highlights: •A new method for estimating w/b ratio and slag content in cement pastes is proposed. •The method is also able to calculate the degrees of reaction of slag and cement. •Reference standards or prior knowledge of the binder composition are not required. •The method was tested on samples with varying w/b ratios and slag content