Influence of TiO2 on the melting property and viscosity of Cr-containing high-Ti melting slag

A study on the melting and viscosity properties of the chromium-containing high-titanium melting slag(CaO–SiO2–MgO–Al2O3–TiO2–Cr2O3) with TiO2 contents ranging from 38.63 wt% to 42.63 wt% was conducted. The melting properties were investigated with a meltingpoint apparatus, and viscosity was measured using the rotating cylinder method. The FactSage 7.1 software and X-ray diffraction, in combination with scanning electron microscopy–energy-dispersive spectroscopy(SEM–EDS), were used to characterize the phase equilibrium and microstructure of chromium-containing high-titanium melting slags. The results indicated that an increase in the TiO2 content led to a decrease in the viscosity of the chromium-containing high-titanium melting slag. In addition, the softening temperature, hemispheric temperature, and flowing temperature decreased with increasing TiO2 content. The amount of crystallized anosovite and sphene phases gradually increased with increasing TiO2 content, whereas the amount of perovskite phase decreased. SEM observations revealed that the distribution of the anosovite phase was dominantly influenced by TiO2.

Optimization of operating parameters and kinetics for chloride leaching of lead from melting furnace slag

The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated.The effects of operating parameters such as leaching time,NaCl concentration,FeCl3concentration,liquid/solid ratio,stirring rate,temperature,and particle size on recovery of lead were studied and the optimization was done through the response surface methodology(RSM)based on central composite design(CCD)model.The optimum conditions were achieved as follows:leaching time60min,80°C,stirring rate800r/min,NaCl concentration200g/L,FeCl3concentration80g/L,liquid/solid ratio16,and particle size less than106μm.More than96%of lead was effectively recovered in optimum condition.Based on analysis of variance,the reaction temperature,liquid/solid ratio,and NaCl concentration were determined as the most effective parameters on leaching process,respectively.Kinetics study revealed that chloride leaching of galena is a first-order reaction and the diffusion through solid reaction product and chemical reaction control the mechanism.The activation energy of chloride leaching of galena was determined using Arrhenius model as27.9kJ/mol.

STUDY ON SLAG DETACHABILITY AND STICK SLAG MECHANISM OF SSFCE

In the paper, the effects of linear expansion coefficient and basic index of melting slag on the detachability of self shielded flux cored electrode (SSFCE) are investigated. An equation is obtained on the principles of ceramics and mineralography which predict the detachability of basic SSFCE. In addition, stick slag mechanism of SSFCE is analyzed.

Calculation Model for Surface Tension of Slag Melt

Based on the coexistence theory of slag melt structure and Butler’s equation,a new calculation model has been proposed for the calculation of surface tension of slag melt.This model establishes a specific correlation between surface tension and mass action concentrations(activities) in the melt and on its surface on the basis of inner and surficial structures of slag melt.Calculated surface tensions of CaO-SiOand MnO-SiOslag melts are consistent with those measured.Furthermore,iso-surface tension lines of CaO-MnO-SiOslag melt have also been calculated.

Niobium and phosphorus behavior during melting-separation process of pre-reduced niobium ore concentrate

The pre-reduced Bayan Obo ferroniobium（FeNb）ore concentrate block was taken as raw materials for studying the physical properties of niobium-enriched slag and changes in niobium recovery rate.In addition,the dephosphorization rate of the slag under different melting-separation conditions was investigated using the melting-separation test.The research results demonstrate that（i）the niobium recovery rate and dephosphorization rate of the slag decrease with the increase in melting-separation temperature;（ii）the niobium recovery rate of the slag initially increases and then decreases with increase in basicity and time;and（iii）the dephosphorization rate of the slag increases with the increase in basicity and time.When the test was performed under the conditions of basicity of 0.6-0.7,time of 7-10min,and temperature of 1400-1450°C,the niobium recovery rate and dephosphorization rate are over 96%and 95%,respectively.By scanning electron microscopy,it is observed that niobium mainly exists in the form of calcium and titanium silicate within the slag phase,with uneven distribution.