A. Romero-Serrano

Effect of copper, sulfur, arsenic and antimony on silver distribution in phases of lead blast furnace

Abstract An experimental study was carried out to estimate the effect of the lead impurities on the silver distribution in the phases formed in the lead blast furnace. Samples of sinter with different contents of Cu, S, As and Sb were equilibrated under reducing atmosphere ( p (CO)/ p (CO 2 )=2.45) at 1573 K in a tube furnace and slowly cooled. The samples were characterized by scanning electron microscopy and microanalysis (SEM-EDS). There were five immiscible phases: slag (CaO, FeO and SiO 2 ), matte (S, Cu and Fe), speiss (As, Fe and Cu), Cu–Sb phase and lead bullion (Pb, Ag, Sb, Cu, etc). The results showed that Cu and Sb promote silver losses during the process since they form a liquid solution with higher silver solubility than liquid bullion. Sulfur and arsenic react with copper to form the matte and speiss phases, respectively. The effect of S and As is to reduce the amount of Cu–Sb alloy and then the silver losses from the bullion.

Effect of CaO/SiO2 and Fe/SiO2 ratios on phase equilibria in PbO-ZnO-CaO-SiO2-“Fe2O3” system in air

Abstract Experimental studies on phase equilibria and liquidus temperature in the PbO-ZnO-CaO-SiO 2 -“Fe 2 O 3 ” system, with the mass ratios of CaO/SiO 2 =1-1.6 and Fe/SiO 2 = 1.3-1.7, and 40% PbO and 8% ZnO, were carried out between 1273 and 1573 K. Slags were equilibrated at 1273 to 1573 K and cooled rapidly by quenching. The XRD and SEM-EDS results showed that the slag compositions are in the franklinite primary phase field. Calcium and lead silicates are formed between 1373 and 1473 K. The Ca/Pb silicate and magnetoplumbite phases are partially formed by an incongruent reaction. The experimental and thermodynamical results showed that the liquidus increased by increasing CaO/SiO 2 mass ratio and decreasing Fe/SiO 2 mass ratio.

Inyección de mineral de manganeso en acero liquido

A theoretical and experimental analysis is carried out to estimate the rate of MnO reduction when manganese ore is injected into liquid steel with three carbon contents, 0.5, 1.0 and 2.0 mass % at 1600 °C. It is assumed that there are two reaction zones along the flux injection operation: a transitory reaction between the rising particles and the bulk metal, and the permanent reaction between the metal and the top slag. The experiments were carried out in an open 10 kg induction furnace using A1203 refractory. The results show that the transitory reaction plays a more important role in the powder injection process than the permanent reaction. The reduction of MnO with silicon is more important when the basicity of the slag is high; this is because the aSi02 decreases as the slag basicity is increased. However, when the slag basicity is low and the initial carbon content in steel is high the reduction of MnO with silicon becomes less efficient, although silicon still remains better reducing agent than carbon.