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Transalloys is currently the largest producer of silicomanganese in Africa, with its smelter complex based outside the town of eMalahleni, in the Mpumalanga Province of South Africa. It operates five open submerged arc furnaces and produces an alloy containing > 16% Si, < 2% C, and > 65% Mn. Manganese ore is the main source of manganese units, supplemented by dust and alloy fines recycled into the furnace as briquettes. Transalloys has mature technology and systems in place, which are described in more detail in this paper.

Arcmon is a device that is used to quantify the amount of arcing (expressed as arc power fraction) that takes place in submerged-arc furnaces (SAFs). During a trial installation on a 48-MVA SAF used for the production of SiMn, differences in arcing behavior between the three different electrodes were observed, with the amount of arcing on one electrode being significantly higher than on the other two. During the subsequent excavation of the SAF, the increased amount of arcing had been attributed to the presence of a hard build-up below the electrode. Phase chemical analysis of the hard build-up indicated that it consisted primarily of portlandite (a reaction product of calcium carbide that probably reacted with the water used to cool down the burden during excavation) and silicon carbide. In comparison, the coke-bed below one of the other electrodes consisted mainly of graphite, silicon carbide, and phases which will typically precipitate from slag upon cooling, i.e. phases expected to be present in a coke-bed. The presence of such a large build-up of carbide material is undesirable as it effectively reduces the volume of coke-bed available for the reduction reactions to occur. The study indicated that Arcmon could potentially be applied as an early warning system to identify the presence of such a build-up.

Submerged-arc furnace technology is applied in the primary production of ferroalloys. Electrical energy is dissipated to the process via a combination of arcing and resistive heating. In processes where a crater forms between the charge zone and the reaction zone, electrical energy is dissipated mainly through arcing, e.g., in coke-bed based processes, through resistive heating. Plant-based measurements from a device called “Arcmon” indicated that in silicomanganese (SiMn) production, at times up to 15% of the electrical energy used is transferred by arcing, 30% in high-carbon ferromanganese (HCFeMn) production, compared with 5% in ferrochromium and 60% in ferrosilicon production. On average, the arcing is much less at 3% in SiMn and 5% in HCFeMn production.

Excavation of industrial-scale furnaces allows for the systematic study of reaction sequences by identifying the different reaction zones within the furnace. In 2013, Transalloys excavated a 48 MVA submerged arc furnace that was used for silicomanganese production using the ore-based route. The excavation method was reported elsewhere as was observations made in terms of refractory wear and modes of electrical energy dissipation prior to excavation. The paper presented here, reports on the process reaction zones observed during the excavation and subsequent phase chemical analyses of a number of process samples obtained during the excavation. The zones identified were a loose burden zone, a dry coke-bed zone, a wet coke-bed zone, a hard build-up zone, and an alloy zone. The results are compared to observations made in the excavation of an industrial-scale SAF and a pilot-scale SAF in Norway. The presence of the hard build-up zone below one of the electrodes and absence of a slag zone below all three electrodes are unique features of the SAF excavated at Transalloys.

Purpose: To evaluate the safety and efficacy of dexamethasone intravitreal implant (Ozurdex, DEX implant) 0.7 and 0.35 mg in the treatment of patients with diabetic macular edema (DME).Design: Two randomized, multicenter, masked, sham-controlled, phase III clinical trials with identical protocols were conducted. Data were pooled for analysis.Participants: Patients (n = 1048) with DME, best-corrected visual acuity (BCVA) of 20/50 to 20/200 Snellen equivalent, and central retinal thickness (CRT) of ≥300 μm by optical coherence tomography.Methods: Patients were randomized in a 1:1:1 ratio to study treatment with DEX implant 0.7 mg, DEX implant 0.35 mg, or sham procedure and followed for 3 years (or 39 months for patients treated at month 36) at ≤40 scheduled visits. Patients who met retreatment eligibility criteria could be retreated no more often than every 6 months.Main Outcome Measures: The predefined primary efficacy endpoint for the United States Food and Drug Administration was achievement of ≥15-letter improvement in BCVA from baseline at study end. Safety measures included adverse events and intraocular pressure (IOP).Results: Mean number of treatments received over 3 years was 4.1, 4.4, and 3.3 with DEX implant 0.7 mg, DEX implant 0.35 mg, and sham, respectively. The percentage of patients with ≥15-letter improvement in BCVA from baseline at study end was greater with DEX implant 0.7 mg (22.2%) and DEX implant 0.35 mg (18.4%) than sham (12.0%; P ≤ 0.018). Mean average reduction in CRT from baseline was greater with DEX implant 0.7 mg (−111.6 μm) and DEX implant 0.35 mg (−107.9 μm) than sham (−41.9 μm; P < 0.001). Rates of cataract-related adverse events in phakic eyes were 67.9%, 64.1%, and 20.4% in the DEX implant 0.7 mg, DEX implant 0.35 mg, and sham groups, respectively. Increases in IOP were usually controlled with medication or no therapy; only 2 patients (0.6%) in the DEX implant 0.7 mg group and 1 (0.3%) in the DEX implant 0.35 mg group required trabeculectomy.Conclusions: The DEX implant 0.7 mg and 0.35 mg met the primary efficacy endpoint for improvement in BCVA. The safety profile was acceptable and consistent with previous reports.

To compare efficacy and safety between twice-daily and four-times-daily regimens of pemirolast 0.1% in allergic conjunctivitis patients.This investigator-masked trial recruited 169 patients, with a positive skin prick test, +2 itching and hyperemia. Patients were randomized to two times daily (t.i.d.) or four times daily (q.i.d.) treatment during allergy season. Evaluation was at 0, 2 and 4 weeks, with itching and hyperemia at week 4 as the primary endpoints. Analysis used last observation carried forward (LOCF) and analysis of variance (ANOVA) for efficacy, factoring treatment and center variations. The basis of the statistical evaluation was to confirm parity between two treatments, via noninferiority hypothesis testing. A 95% confidence interval (CI) with an upper limit ofor = 0.5 was set to assess non-inferiority or to conclude if schedules were statistically similar.B.i.d. and q.i.d. baselines were similar, respectively, for itching (2.6 and 2.8) and hyperemia (2.3 and 2.2). Week 4 itching was statistically non-inferior between treatments (1 b.i.d. versus 0.8 q.i.d.), with a mean treatment difference of 0.17 (-0.13, 0.47, Deltaor = 0.5). Week 4 hyperemia was comparable (1.2 for b.i.d. versus 1.0 for q.i.d). Week 2 scores and mean change from baseline (weeks 2 and 4), patient diary data, and investigator assessments were comparable. Both regimens were well tolerated with no differences in adverse events were observed.B.i.d. dosing was statistically non-inferior to q.i.d. dosing with respect to itching and hyperemia. Both regimens were similarly well tolerated in allergic conjunctivitis patients.