Non-ferrous Slags Research Articles

Processing Techniques for Difficult-to-treat Ores by Combining Chemical Metallurgy and Mineral Processing

This paper is concerned with a review of published literature on the processing of difficult-to-treat ferrous and nonferrous ores that have very fine liberation size and have constituent minerals with similar properties for which the conventional mineral processing techniques are ineffective. By altering mineralogy either pyrometallurgically or hydrometallurgically, the low cost methods of mineral processing could be applied on ores which are complex and refractory in character. It briefly reviews methods such as magnetizing roasting and direct reduction for ferrous ores and discusses the pyrometallurgical pre-treatments on nonferrous ores, such as sulfidizing roasting, roast-flotation, segregation process and matte separation process, and hydrometallurigcal pre-treatments to extract valuable metal values by applying leach-precipitation-flotation method, and ion flotation. Application of a combination of chemical metallurgy and mineral processing methods to solid waste materials, in particular, steel plant wastes, nonferrous slags, smelter flue dusts and anode slimes have also been briefly discussed.

Some Interesting Aspects of Non-ferrous Metallurgical Slags

Analyse des laitiers de la metallurgie non ferreuse (production Cu, Ni). Influence de la temperature sur la solubilite des laitiers. Systeme FeS−FeO−SiO 2

Supplementary cementing materials for concrete

This ~ublication Dresents a state of the art review of knowledge on the properties, uses, benefits, and limitations of supplementary cementing materials. As such, it provides an UD-to-date and com~rehensive reference work for structural engineers, concrete technologists, specifiers, and those in the concrete manufacturing and supply industry. The book deals with natural pozzolans, fly ash, silica fume, granulated blast-furnace slag, and nonferrous slags. All but the last group of materials are covered in a 1986 Canadian Standards Association Standard CAN/CSA-A23.5-M86 Supplementary Cementing Materials. This book is, therefore, a timely synthesis of data for those who wish to specify or use such materials. Each of the seven chapters are written by recognized experts in the field and include American and Norwegian authors, as well as Canadian. Each chapter covers the characteristics of the material and its effects on the important properties of fresh and hardened concrete. Some of these materials, mainly fly-ash and slag, are in widespread use in many parts of Canada. Currently, the focus of all concrete technologists is with durability because so much of the concrete in the structures that comprise our infrastructure is exhibiting premature deterioration. This book gives guidance on how the use of these materials in concrete can improve the thermal and permeability characteristics, resistance to chemical attack, and the reduction of deleterious expansion due to alkali-aggregate reactivity. Guidance is given by reference to published, mostly recent, work. Each chapter makes frequent reference to published data and concludes with an extensive and useful list of references. Guidance is also given in the special uses of each material. The format of the book is attractive and clear and at the published price is very good value. This is a timely and valuable publication.

Application of differential thermal analysis to determine the influence of the thermal history on the degree of vitrification in the system CaO-MgO-SiO2

Diopside, CaO.MgO.2SiO2, and glasses of the same stoichiometry are fundamental phases in non-ferrous slags. Samples of this composition, prepared from the melt at different cooling rates, were examined via DTA and IR spectra. A correlation was found between the degree of vitrification and the magnitude of the exothermic effect at around 870 °C. The same dependence exists for some slags. No exotherm was observed for well-crystallized samples. The reactivity with water was assigned to the glass content.

Correlations of electrical conductivity to slag composition and temperature

The electrical conductivity of slags is an important factor in the design of electric smelting furnaces. Although there are many experimental studies on this subject, as yet there are no quantitative correlations of conductivity to slag composition and temperature. The objective of this work was to develop such correlations, on the basis of the experimental data by various other authors. The results show that in the concentration range of industrial-type SiO2-CaO-MgO-MnO slags the slag conductivity can be expressed as a linear function of the molar concentrations of the basic oxides; in the concentration range of industrial nonferrous slags, where the iron oxide content is usually over 20 pct, the slag conductivity can be expressed as an exponential function of the molar concentrations of the iron and basic oxides. The effect of temperature on slag conductivity, in the industrial range of interest, can be accounted for by means of an Arrhenius-type of equation.

Bubbling at high flow rates in inviscid and viscous liquids (slags)

The behavior of gas discharging into melts at high velocities but still in the bubbling regime has been investigated in a laboratory modeling study for constant flow conditions. Air or helium was injected through a vertical tuyere into water, zinc-chloride, and aqueous glycerol solutions. High speed cinematography and pressure measurements in the tuyere have been carried out simultaneously. Pressure fluctuations at the injection point were monitored and correlated to the mode of bubble formation. The effects of high gas flow rates and high liquid viscosities have been examined in particular. Flow rates were employed up to 10-3 m3/s and viscosity to 0.5 Ns/m2. In order to attain a high gas momentum, the tuyere diameter was only 3 x 10-3 m. The experimental conditions and modeling liquids were chosen with special reference to the established practice of submerged gas injection to treat nonferrous slags. Such slags can be highly viscous. Bubble volume is smaller than that calculated from existing models such as those given by Davidson and Schuler10,11 due to the effect of gas momentum elongating the bubbles. On the other hand, viscosity tends to retard the bubble rise velocity, thus increasing volumes. To take elongation into account, a mathematical model is presented that assumes a prolate ellipsoidal shape of the bubbles. The unsteady potential flow equations for the liquid are solved for this case. Viscous effects are taken into account by noting that flow deviates from irrotational motion only in a thin boundary layer along the surface of the bubble. Thus, drag on the bubble can be obtained by calculating the viscous energy dissipation for potential flow past an ellipse. The time-dependent inertia coefficient for the ellipsoid is found by equating the vertical pressure increase inside and outside the bubble. This pressure change in the bubble is obtained by assuming that gas enters as a homogeneous jet and then calculating the stagnation pressure at the apex of the bubble.

Studies on the flotation of a non-ferrous slag

The flotation behaviour of a complex non-ferrous slag, which contained tin, lead and copper, as well as willemite, galena and sphalerite, associated with oxidic and siliceous gangue, was investigated. A sulphidization flotation flowsheet producing collective tin-lead-copper and willemite concentrates was developed. The surface chemical changes during the processing were interpreted on the basis of XPS measurements.

Cementitious Properties of Nonferrous Slags from Canadian Sources

Abstract This report presents data on the characterization of nine Canadian nonferrous slags. The characterization includes the determination of grinding energy, fineness, chemical composition, estimates of glass content, pozzolanic activity, and strength development. Grinding the slags to 4000 cm2/g seems to be economically feasible. The chemical analysis indicates that calcium oxide contents for all samples are low with the exception of a lead slag. It is concluded that for research purposes, glass content should be measured with a scanning electron microscope image analyzer. Slag activity should be estimated using the ASTM Specification for Ground Iron Blast-Furnace Slag for Use in Concrete and Mortars (C 989) test. The 28-day index indicates a direct relationship between strength and glass content when determined at 23°C in specimens cured in the moist room. Tests carried out at 38°C fail to confirm that strength development is directly related to vitrification.

Heterogeneous Equilibria and Phase Diagrams

Each year the problem of reviewing in a few pages the large field of heterogeneous equilibria and phase diagrams becomes more difficult. The number of good papers in this field has increased each year as the practical value of the results has become apparent in such widely diverse fields as improvement of metals by alloying or heat treatment, substitution for criti­ cally scarce metals, ferrous and nonferrous slag metallurgy, surface finishing of metals, control of corrosion and oxidation of metals, glass making, develop­ ment of high-temperature refractories, cement technology, geologic ther­ mometry, the origin of rocks, minerals and ores, the separation and purifi­ cation of solid and liquid organic compounds, the preparation and purifica­ tion of chemicals. the utilization of natural products. the development of useful byproducts. and a host of other industrial developments. During this past year the literature has been particularly extensive because of the large number of good papers, published in Russian journals during the past few years, which have just become accessible this year by inclusion in the 1954 volume of Chemical Abstracts. More than 500 papers in the phase-equilibriu m field were noted. In this review we have tried to mention, at least by subject matter, those which contain important pertinent data. One of the best methods for presenting the results on heterogeneous systems is that proposed by Bogue & Newkirk (1) in their review of this subject two years ago in the Annual Review of Physical Chemistry. This method, based on chemical composition, divides the subject into five broad categories: (a) aqueous salt systems, (b) organic systems, (c) anhydrous salt systems, (d) metallic systems, and (e) oxides and refractory systems. Be­ cause of their long-range importance, we first of all call attention to the re­ cent advances in graphical methods, theoretical studies, new experimental techniques and apparatus, and cite reviews of certain aspects of phase equilibria. GRAPHICAL METHODS AND THEORETICAL STUDIES