Settling of Copper Phases in Lime Modified Iron Silicate Slag

Copper in discarded slag decreases the profits and copper recovery during the pyrometallurgical extraction processes. The copper losses to slag can be reduced by using a settling furnace, in which mechanically entrained copper droplets separate from the slag under the action of gravity. The settling rate of entrained droplets can be increased by modifying the slag composition and, thus, the slag properties, which are known to influence the settling rate. The knowledge of industrial CaO slag modification in a reduced iron silicate slag with a Fe/SiO2 ratio close to unity is limited. An industrial trial was thus conducted in an electric settling furnace, where the slag had been pretreated in a fuming furnace, to investigate the effect of CaO slag modification on the final slag copper content. Slag samples were collected from the ingoing and outgoing slag and from within the furnace of batches modified with CaO up to about 16 wt %. The trial was evaluated by comparing the final slag copper content and the copper recovery in the settling furnace. The results indicate that the settling becomes more efficient with the CaO modification as the final slag copper content decreased with increasing CaO content.

Development of the model complex of the expert system of control and management of the slag mode in modern mixed blast furnace conditions

The aim of the work is to develop physicochemical bases for predicting the technological properties of finite blast furnace slags, algorithmic and software for the subsystem for diagnosing the slag regime of blast furnace smelting. Based on experimental data on the properties of natural finite blast furnace slags, predictive models for calculating the viscosity of the final slag at a temperature of 1400-1550 °C were improved by including in the model structure an integrated slag melt index of the parameter Δe, which reflects the individual effect. Using the integral parameters of the slag melt characterizing the charge state of the system Δe and the structure of the slag ρ, an equation was developed to determine the viscosity of the slag at any temperature corresponding to the slag temperature at the cast iron outlet. As a result of analytical research, a predictive model for determining the enthalpy of slag depending on the integral parameters Δe and ρ and the temperature of the melt has been developed. It is shown that the viscosity characterizes the fluidity of the slag and provides desulfurizing and drainage properties. The calculation of the viscosity for the specified production of pig iron by the chemical composition of the slag is carried out according to the basic model of slag in a conditionally "homogeneous" state and taking into account its heterogeneity. This takes into account the presence of macroheterogeneous inclusions formed when using coke with low strength characteristics and due to incomplete combustion of pulverized coal fuel in the blast furnace. The improved models for evaluating the viscosity and enthalpy of the final slag are software implemented in the new version of the «Slag» system for operational control of the slag mode of blast furnaces in Ukraine. Rapid assessment of the slag mode using the «Slag» system as part of the DCS allows you to effectively and at a modern level solve the problems of optimizing the slag mode and the quality of pig iron in modern conditions of blast furnace smelting.

Bioleaching of Valuable Components from a Pyrometallurgical Final Slag

Pyrometallurgical copper final slag was subjected to leaching by means microbial cultures of three different groups based on their optimum temperature for growth and activity: mesophilic and moderate thermophilic bacteria, and extreme thermophilic archaea. The leaching experiments were performed by the shake-flask technique and in agitated bioreactors under batch and continuous-flow conditions. The effect of the most essential factors (particle size, pulp density, pH, aeration) on this process was studied. The highest rates of extraction of the non-ferrous metals (Cu, Zn, Co) and iron were achieved by means of some archaea but at relatively low pulp densities (5 – 10%). Some moderate thermophilic bacteria were the most efficient at the higher pulp densities (15 – 20 %). The, leaching by some mesophiles at pH 3.0 – 3.5 was also very attractive since it was connected with high extractions of these metals (about 85 – 92% at 20% pulp density), much lower acid consumption and low solubiliation of fayalite which resulted in the production of pregnant solutions suitable for the recovery of the dissolved non-ferrous metals.

Activity Calculation Model for Oxygen Converter Final Slag

In this paper the activity calculation model for SiO2-Al2O3-CaO-MgO-FeO-MnO slag system has been established according to the molecule-ion coexistence theory. From that the activity of each component in the converter slag at steelmaking temperature can be calculated and then provides the basis for analyzing the equilibrium distribution of element between slag and steel, as well as thermodynamics analysis related to the activity.With the increasing of FeO mass fraction, the activity of 3CaO.SiO2 shows a significant decreasing trend and the activity of MnO.SiO2 and 2MnO.SiO2 increases slowly. The activity of 3CaO.SiO2 increases at first then decreases, with the increasing of basicity. When the basicity w(CaO)/w(SiO2)=3, the activity of 3CaO.SiO2 reaches its maximum value. The activities of MnO.SiO2 and 2MnO.SiO2 decrease gradually.

Research and Application on Parameter Optimizing of Oxygen Lance Nozzle on Converter for Semi-Steel Making

In order to meet the need of production and promote the smelting efficiency of converter, Pangang Vanadium-extracting&Steel Making Plant optimized oxygen lance nozzle according to the situation of primary 120t converter semi-steel making and have inspected new oxygen lances smelting effect in industrial test. The test shows that the average oxygen blowing intensity raised 0.19m3/t·min with optimized nozzle, shortened oxygen blowing time by 56s,total iron in final slag reduced 0.7%, dephosphorizing rate rose to 82.10% from 79.06%, which developed a good result.

Experimental Study on Optimization of Slag Splashing Modifiers with Magnesite Tailings

The pile up of Magnesite Tailings cause serious environment pollution and mineral resources waste. When making the low-carbon steel or the ultra low-carbon steel in middle or small size converters, the slag superheat is always higher due to the higher tapping temperature. In order to reduce the tapping temperature, after blowing is also needed, which wil cause the contents of FeO in final slag get increased, the slag with lower viscosity, and the contens of MgO in final slag cant get saturated. So Slag Splashing should not proceed immediately that we must slag Modifiers. The modifier was synthesized by calcined magnesite and anthracite powder,modifier takes the treatment of slag. The experimental result show that the slag has a higher melting point and a suitable viscosity to achieve the requirements of slag splashing.

Optimization of Steelmaking Process for 200t Converter

To solve the problems appeared in the initial operation period of 200t BOF such as low heating velocity, high TFe content in final slag, severe lining erosion, etc, optimization of steelmaking process is carried out. Metallurgical effects are greatly improved after optimization: slag-forming time is shortened by 0.9min; oxygen consumption is lowered by 1.5 m3 per ton steel; carbon content of aimed molten iron is increased by 0.031% while oxygen activity of which is decreased by 206ppm. TFe content of BOF slag is reduced by 0.84% on average.

Bottom-Blown Stirring Technology Application in Consteel EAF

Bottom blown stirring technology application in EAF was studied in this paper. The basic principle of bottom blowing process was researched, the bottom blown stirring can give strong stirring effect on the molten steel bath, thus bath mixing time was shortened, decarburization and dephosphorization were improved, however over stirring would lead to liquid steel incontact with atmosphere air. Reasonable process was considered on Consteel EAF. results show that: with bottom-blown stirring technology, decarburization and dephosphorization increase significantly; oxygen and lime consumption decrease; content of FeO in final slag reduces; and heat time becomes short.