A Study on the Metallurgical Characteristic of Hammer Scale Produced through Traditional Iron-making Experiments

This study attempted to investigate the metallurgical characteristic through material scientific analysis of hammer scale produced as a direct smelting method restoration experiment for each raw material of iron. To this end, four hammer scale groups were set up, respectively, by experimenting with Gyeongju-Gampo Iron sand and Yangyang Iron ore. For the analysis, principal component analysis, compound analysis, microstructure observation, and chemical composition were confirmed. As a result of principal component analysis, as forging and refining progressed, the content of Fe increased and the content of non-metallic objects decreased. As a result of compound analysis, iron oxide-based compounds were identified. As a result of confirming microstructure and chemical composition, Wüstite and Fayalite were observed overall, and agglomerated Wüstite were observed in some. Magnetite on shape of polygon and pillar was observed. In addition, it was confirmed that internal defects, impurities, and non-metallic interventions gradually decreased. In the future, it is necessary to investigate the metallurgical characteristic through material scientific analysis of hammer scale produced through restoration experiments using various raw material of iron, and compare them with those excavated from Iron manufacture ruins.

Lead Recovery from a Lead Concentrate throughout Direct Smelting Reduction Process with Mixtures of Na2CO3 and SiC to 1000 °C

Lead was recovered through a direct smelting reduction route from a lead concentrate by using mixtures of Na2CO3 and SiC to 1000 °C. The lead concentrate was obtained from the mining State of Zacatecas, México by traditional mineral processing and froth flotation. The experimental trials showed that 86 wt.% of lead with a purity up to 97% can be recovered from the lead concentrate by a single step reduction process when 40 wt.% Na2CO3 and 0.4 g SiC were used in the initial charge. The process was modeled in the thermodynamic software FactSage 7.3 to evaluate the effect of adding different amounts of Na2CO3 on the lead recovery rates while holding constant the SiC amount and temperature. The stability phase diagram obtained showed that an addition of 34 wt.% Na2CO3 was enough to reach the highest lead recovery. It was observed that the interaction of Na2CO3 and SiC at a high temperature promotes the formation of C and Na2O, and SiO2, respectively, where the Na2O partially bonds with silica and sulfur forming Na2S and sodium silicates which may decrease the SO2 emissions and increase the weather degradation of the slag. The PbS was mainly reduced by the produced C and CO formed by the interaction between Na2CO3 and SiC at 1000 °C. The predicted results reasonably match with those obtained experimentally in the lead recovery rates and compounds formation.

Characterization of Early Iron-Production Technologies in Chungju, Korea

In the presentation, previous archaeological achievements as well as analytical studies conducted on ironwork sites in Chungju are reviewed. In addition, the early iron production technology in the area can be characterized based on various evidences. Extensive ironworks were conducted at various sites concentrated especially in Chungju. Direct smelting was still the main technology until rather later on. Substantial amounts of tap slag and their analytical features support this idea. In addition, comprehensive studies as to the structure of furnaces and tuyeres used to do ironwork and their technical relationships also need to be discussed. Furthermore, smithing processes, which were mostly conducted at the smelting sites, were also described in detail so that the general ironworking process could be identified.

Feasibility of nickel extraction from Indian chromite overburden by solid state reduction and smelting route

The present work demonstrates the extraction of nickel from low-grade chromite overburden by using solid state reduction and direct smelting route. Goethite & Quartz are present as major phases whereas chromite, hematite were identified as minor phases in the mineral. Solid state reduction of pellets were carried out inside a horizontal tube furnace at 1000?C, 1200?C, 1400?C for 30, 60, 90 and 120 minutes respectively with creating reducing atmosphere. Pellets of varying basicity (i.e. 0.5, 0.6, 0.7, 0.8 and 0.9) were used directly in the EAF for smelting studies. Highest percent of nickel (2%) having ~ 91% recovery were obtained in solid state reduction route for pellets which was reduced at 1400?C for 120 minute. Similar recovery (~90%) of nickel was obtained inside the ingot (0.67% Ni ) by using pellets of 0.9 basicity through smelting route. From the present investigation, it could be concluded that the solid state reduction as well as smelting routes are feasible for the recovery of nickel from low grade chromite overburden. The production of nickel pig (low grade ferronickel) could also be feasible by smelting route.

Comparison of Gold Yield with Traditional Amalgamation and Direct Smelting in Artisanal Small-Scale Gold Mining in Uganda

Background. The amalgamation method used by artisanal small-scale miners is the single largest source of global mercury emission. The goal of the ‘Free Your Mine’ project is to stop mercury use in artisanal and small-scale mining. Objectives. The aim of the present study was to compare gold recovery and time consumption between the amalgamation method and direct smelting, using borax for smelting under standardized conditions. Materials and Methods. This was an experimental study in a pragmatic setting in the mining community of Tiira, Uganda. Standardized amounts of gold ore of equal quality were processed with the local amalgamation method and with the Philippine mercury-free method as practiced by miners from Benguet in the Philippines, and the gold yield and time consumption were compared. Results. The amalgamation method took 53 minutes and recovered 1.0 g of pure gold. The miners used 4 g of mercury in the processing. The Philippine mercury-free method took 62 minutes and recovered 1.4 g of pure gold. Conclusions. The Philippine mercury-free method recovered 40% more gold than the amalgamation method but took 9 minutes longer. The Philippine mercury-free method is a viable alternative to amalgamation. Competing Interests. The authors declare no competing financial interests.