Papers by Keyword: Slag

Abstract: The expediency of processing iron-containing concentrate with low iron content, increased content of manganese and copper is considered in the article. To process such a concentrate, a metallization process is proposed to produce sponge iron with a reducing agent - carbon. It was found that in solid-phase reduction at 1150 °C iron is reduced to a greater extent, as well as small particles with a copper content of about 95%, manganese is not recovered. The simulation process of metallization with carbon at a temperature of 1250 °C shows that iron is mainly distributed in the metallic phase, to a lesser extent in slag phases, manganese is distributed in two phases - metal and slag, copper is presented as a separate phase of metallic copper in the composition with iron alloys, and also composes a part of iron alloys. The reduction degree from concentrate to the metallic part is 80 - 91% for iron and 95 - 98% for copper. The presence of metallized particles of various sizes, representing phases of iron with manganese and copper was found in the slags.

Abstract: The paper considers the existing problems of the production of ceramic products in the territory of the Russian Federation, presents the priority directions of development of this industry. The study includes the determination of the properties of samples based on the raw material base of the Orenburg region, namely, waste generated during the development of brown coal from the Tyulgansk deposit - white and red clays and nickel slag of OJSC Yuzhuralnickel Combine of the Orenburg region. The study presents data from the study of the technological properties of the raw materials, the development of the composition of the ceramic mixture. The influence of the material composition of the clay / slag mixture on the physic mechanical characteristics of the products of the experimental compositions was determined: compressive strength, fire shrinkage, water absorption and density.

Abstract: The paper deals with investigation of changes in selected properties of concretes which have been exposed to acid rain. The experiments took place in laboratory under model solution representing acid rain (40 % HNO₃, 60% H₂SO₄) over a period of 7 weeks. The concrete samples investigated were concretes with ordinary Portland cement only as well as concretes of high-portion-mineral-addition-cements as well. Disruptions, cracking and samples' falling apart at the end after 7-week exposure to acid rain were observed by evaluation of visual changes. Based on the determination of the other parameters the results are not so uniform that is why the clear statement of more suitable concrete resistant to acid rain is not given. The assumption that a high-mineral concrete mix would be more suitable for environments exposed to acidic rain was not confirmed in this experiment.

Abstract: Limestone and slag blended concrete is an innovative concrete which belongs to the family of limestone calcined clay cement (LC3) concrete. Strength is an important property of structural concrete. This study shows artificial neural networks (ANN) and gene expression programming (GEP) models for predicting strength development of limestone and slag blended concrete. ANN model consists of an input layer, a hidden layer, and output layer. GEP model consists of the sum of three expression trees. The input parameters of ANN and GEP models are mixtures and ages. The output parameter is a strength. The correlation coefficients of ANN and GEP model are 0.99 and 0.98, respectively. Both ANN and GEP model can produce prediction results of the strength of ternary blended concrete reliably.

Abstract: The reducibility of titanomagnetite iron ore materials (agglomerate, pellets) with various TiO₂ contents are studied. The mineralogical features of agglomerate and pellets before and after reduction are investigated. Calculations of technical and economic indicators of blast furnace smelting using iron ore materials with different TiO₂ contents are carried out. It is shown that an increase in the content of titanium dioxide in pellets and agglomerate (with an increase in the amount of concentrate introduced into them) does not change the quality of iron ore preparation for blast furnace smelting.

Abstract: The invention of Chinese paktong was well-known in ancient China from at least the fourth century AD and is considered to be one of the most important inventions in the history of metallurgy, facilitating economic and material exchange in the West during the 17-19^th centuries. As recent investigations into the relevant archives of paktong show, it is recognized that the early industry of such metal had intimate connections with Yunnan and Sichuan provinces. Due to the recent year research on some ancient metallurgical remains of Chinese paktong in Yunnan, it shows that the slags in the sites of Mouding and Jiangyin were from the specific metallurgical process, probably by intentionally accumulating nickel with iron. Both sites were likely to be the places of mining or refining and roasting the ores, but the outcomes from them might be the roughly finished products.

Abstract: In the presentation, previous archaeological achievements as well as analytical studies conducted on ironwork sites in Chungju are reviewed. In addition, the early iron production technology in the area can be characterized based on various evidences. Extensive ironworks were conducted at various sites concentrated especially in Chungju. Direct smelting was still the main technology until rather later on. Substantial amounts of tap slag and their analytical features support this idea. In addition, comprehensive studies as to the structure of furnaces and tuyeres used to do ironwork and their technical relationships also need to be discussed. Furthermore, smithing processes, which were mostly conducted at the smelting sites, were also described in detail so that the general ironworking process could be identified.

Abstract: There are shown studies on development of the alkali-activated slag cements and concretes using Chinese raw materials. Such cements and concretes are able to provide high performance characteristics of materials and constructions under exposure of sea climate. The tests had been done for compliance with the requirements set in the national standards of P.R.China and were determined characteristics of strength, wet conditions shrinkage, freeze-thaw resistance, corrosion and weather resistance, biodegradability, water permeability, bond strength between concrete and reinforcement. The obtained positive results of tests allowed to recommend them for a pilot-scale production of the developed materials in sea construction for protection of the sea coastal line in the P.R.China.

Abstract: Aluminosilicate materials are generally considered electrical insulators. In order to achieve enhanced electrical conductivity these materials must doped with suitable conductive admixtures such as carbon black. These composites gain the importance in the new field of applications such as self-sensing materials or self-monitoring structures. This paper presents a study on self-sensing properties of alkali-activated slag composite with 2 and 4% of carbon black as conductive filler during repeated flexural and till fracture loading in the configuration of three-point bending test. The results showed that best performance of the self-sensing properties was achieved with 4% of carbon black, though both the compressive and flexural strengths were deteriorated.

Abstract: This paper studies the fundamental research and development of sprayed cement-based mixture designed to withstand the chemically aggressive conditions. The aim of this paper is to verify the possibilities of usage of suitable secondary raw materials as a substitution of a binder and filler of the original mixture while preserving or improving the physical-mechanical properties. In this part of the research was studied the possibility to substitute the binder in rate of 20-60 wt.% by high temperature fly ash and the whole filler by foundry sand and slag. Test samples were made from nine recipes, in which was monitored the influence of secondary raw materials on the compressive strength and the water absorption after 28 days of curing. The results of this paper show, it is possible to successfully substitute part of the binder by high temperature fly ash and the filler wholly by foundry sand in the sprayed mixture. These optimized recipes showed positive influence mainly in the long-term on mechanical properties.