Effect of Oily Sludge Treatment with Molten Blast Furnace Slag on the Mineral Phase Reconstruction of Water-Quenched Slag Properties

Blast furnace slag, which is the main by-product of the ironmaking process discharged at 1450 °C, contains high-quality sensible heat, while oily sludge is the main solid waste produced in the process of gas exploration, storage, and transportation. The energy and resource utilization of blast furnace slag is complementary to the environmentally friendly treatment of oily sludge, which has provided a new idea for the multi-factor synergistic cycle and energy transformation of the two wastes. The pyrolysis of the oily sludge with the molten blast furnace slag was conducted in the current paper. Results showed that the oily sludge was rapidly pyrolyzed, and the heavy metal elements in the oily sludge were solidified. The solidification rate of the heavy metals exceeds 90%, except for vanadium. The reconstituted water-quenched blast furnace slag still has good activity, and it will not affect the further use of the slag after pyrolysis (BFS-P).

Slag Properties in the Primary Production Process of Mn-Ferroalloys

The thermodynamic and kinetic properties of the carbothermic reduction of MnO in the five-component slag, MnO-SiO2-CaO-MgO-Al2O3, is critical in the production process of Mn-ferroalloys. While the reduction rate is mainly dependent on the presence of a solid MnO phase in the slag for Mn-Fe-alloys, the rate for the Mn-Si-Fe alloys has two distinct steps, a slow step followed by a fast step. The extent of the slow step has been shown to be dependent on the S content in the slag. The thermo-physical properties of viscosity, density, interfacial tension and electrical resistivity is reviewed, and these properties are mainly determined by the total basicity.

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.

Thermodynamic study of oxide phase compositions at reducing iron ore coosit by coals of Karazhyra deposit

Application of coals as reducing agents in the direct iron reducing process is a perspective way. For solid-phase iron reducing from iron ore concentrate of Bapy deposit, Republic of Kazakhstan, application of coals of Karazhyra deposit was proposed. Chemical composition of iron ore concentrate of Bapy deposit is presented. By application of methods and means of thermodynamic simulation, analysis of oxide phase composition was carried out. As a result of thermodynamic studies, it was revealed that at reducing of concentrate of specified composition, iron and aluminum oxides, magnesium, calcium, barium, and alkaline metals silicates, sulfides and phosphor compounds are presented in the oxide phase. A dependence of oxide phase parameters on temperature and coal rate was established. It was shown that a number of aluminum oxide, titanium and barium compounds and calcium and magnesium silicates is not practically varying within the whole temperature interval. The number of compounds, containing phosphor, potassium, natrium is decreasing while temperature is increasing due to elements transferring in gas phase. The number of sulfides is decreasing with temperature increase till the whole disappearance in the condensed phase. The number of iron oxides at the temperature higher 872K depends only on reducing agent rate. The number of oxide phase at the temperature lower 853K is maximum, then begins to decrease while the temperature is increasing, the reducing processes are developing and at the temperature of 1013K after completion of reducing process it reaches its maximum value which is not changing then up to temperature 1773K. The studies carried out enable to evaluate slag properties at elaboration of resource-saving technologies of iron direct reducing and can be used at forecasting and evaluation of metallization processes and the further re-melting of materials obtained from Bapy deposit iron ore concentrate of and Karazhyra deposit coals.