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By Beate Ina Jenssen

Ferric iron removal from the nickel electrolyte at Glencore Nikkelverk AS in Kristiansand, Norway, is achieved by precipitation of iron hydroxide followed by filtration, and it is desirable to improve filtration properties of the precipitated iron hydroxide in order to decrease the filtration time. The effect of increasing the residence time from the current 45 min to 75 min and temperature from 65 °C to 90 °C on the filtration properties of the precipitated iron hydroxide (akaganéite) was studied by simulating the industrial process conditions in a continuous reactor setup operating at steady state, using ferrous-containing process solution as feed material. It was possible to decrease the filter cake resistance by both increasing residence time and temperature, but temperature gave the most pronounced effect and reduced the filter cake resistance by one order of magnitude.

By J. M. Boxall

The electrolytic zinc plant at the Bartlesville division of Z.C.A. originally used lead anodes containing only 0.25% silver because only H.G. zinc and alloy was to be produced. In 1984, a small addition of strontium carbonate was made to control the surf ace morphology of the cathodes which reduced short circuits and increased current efficiency. Later a drastic reduction in colloid addition further reduced short circuits. Increased strontium additions allowed the production of some S.H.G. zinc. Increasing the silver content of the anodes reduced the lead in cathodes only slightly. More important, the anode scale that was not removed during anode cleaning, entered the electrolyte and contaminated the cathodes with lead. A piping system has been installed to purge the contaminated electrolyte directly back to the leaching section. This has allowed the plant to produce S.H.G. zinc consistently.

Jan 1, 1990

By Roberto Javier Santiago

This paper tries to make a study about the use of calcium carbide during the tapping in replacement of part of the aluminum used in the furnace tapping, analyzing theoretical consumptions and then transfering the practice to the plant.

Jan 1, 2006

By Yunqing Tian, Wenbin Huang, Weidong Zhang, Xiaopeng Wang, Gele Qing, Xiangjuan Duan

Pellet production requires iron ore concentrates have fine particle size, high specific surface area and good balling performance, so iron ore concentrates appropriate for pelletizing is limited compared to sintering. In order to extend the iron ore resources for pelletizing, the iron ore fines for sinter are studied in this paper.The effect of grinded iron ores o npelletizing, roasting and pellet quality were studied in this paper. The bond grinding index of iron ore fine is between 12.5 and 16.98 kwh/t. The grinded iron ore fine has good balling performance, the drop number and compressive strength of green pellet were improved with increase of grinded iron ore fine ratio. The compressive strength of roasted pellets were decreased with increase of grinded iron ore fine ratio, however it can be reached 2500 N.P −1 while proportioned with more than 80% of magnetite iron ore concentrate.

Mar 1, 2018

By Wilhelm Wendt

About five years ago we showed that it is possible to use the spectral in- formation in the light emitted by the off-gas flame of a PS converter for on-line production control. Very recently measurements have been performed using improved optical equipment and data evaluation software, resulting in both improved accuracy and the establishment of new optical process parameters. Using the optical signals the slag heats could be stopped at a predetermined Cu content of the white metal with an accuracy of +0.2% Cu m the range 74-78% Cu. A good correlation was found between the slag composition and optical data, providing a possibility for on-line monitoring of the SiO2 content of the slag. The measurements indicate the possibility of predicting the optimum end-point of the copper-making stage and having real time information on the impurity removal. Factors influencing the optical parameters, such as blowrate, Pb content, temperature etc. will be discussed.

Jan 1, 1993

The entrainment of copper matte in the slag during the slag skimming stage of a Peirce-Smith converter was studied with a dam break model. Experiments were carried out with a range of fluid pairs where the lighter fluid was allowed to overflow a weir and the amount of entrained heavier fluid measured. The resulting entrainment is measured as the ratio of the heavy to light fluid withdrawn. The fluids include oil-water, water- glycerol and salt solutions-water pairs to cover a wide range of densities and viscosities. It was found that the Richardson number, Ri, correlates the entrainment well. For the case of the liquid-liquid interface initially at the same height as the weir, the entrainment was found to vary with Ri-1/3. The transient flow was simulated with a volume of fluid (VOF) code written in-house and used a stairstep approach to represent flow obstacles. The code was validated against the experimental results with good agreement for the variation of the heights of the two fluid with time. The simulation showed that the prevailing mechanism for entrainment is due to a pressure differential created across the liquid in the converter during pouring resulting in the heavier liquid being rotated upwards and over the weir.

Jan 1, 1999

By Patrick R. Taylor

Sub-micron sized boron carbide powders have been synthesized in a non-transferred arc thermal plasma reactor. Precursors for this synthesis are boric acid or boron oxide powders and methane. The powders produced were characterized in terms of size, shape and purity. Methods to increase the purity of the product were evaluated and included hot water leaching to remove unreacted oxides and controlled temperature, air roasting to remove excess carbon. Theoretical results are also presented on the thermodynamics and mechanisms of the synthesis reactions.

Jan 1, 1994

By Takahiko Okura

Sulphur, with its multiple oxidation states, play critical roles in many processes, ranging from regulating enzymes in plants, to acidifying aquatic systems, and to affecting the global climate. Most of non-ferrous smelters have been contributing to reduce atmospheric emissions of sulfur dioxide to acceptable levels, converting it to sulphuric acid and/or gypsum. However, some amount of SO2 gas is still emitted from isolated smelters. Furthermore, sulphuric acid is competing with involuntary elemental sulphur in the market. This situation puts the non-ferrous metallurgical industries to develop a new sulphur fixation process. This paper briefly describes the new technologies for fixation, followed by the novel proposal to convert SO2 gas to elemental sulphur using organic materials. Finally, the feasibility will be presented technologically and economically.

Jan 1, 2006

By Markku Rytkonen, Shaolong Chen, Ilpo Kylmäkorpi, Hannu Mansikkaviita

Though the Peirce Smith (P-S) converter is a traditional type of furnace, continuous improvement in its mechanical and electrical design is still Kumera's approach. Efforts are made particularly on the following aspects: converter head shape for easy fabrication and structural strengthening, oxidation air swivel joint for low pressure drop and low noise level, wind box for even air distribution to tuyeres, drive unit and its control for reliable and handy operation. These improvements have successfully been applied in recent P-S converter deliveries.

Jan 1, 2009

By J. M. Zhuang

Lignosulfonates, by-products of the sulfite pulping process, have been utilized in a process [1, 2] to treat acidic rock drainage (ARD). This process is referred to as the LignorTM process. In the present study, lignosulfonates were found to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the clotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long term stability of the sludge against leaching. The LignorTM process involves metal chelation with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 ? 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The LignorTM process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the BC Regulations. Compared with the high density sludge (HDS) process, the LignorTM process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability.

Jan 1, 2003

By Fumito Tanaka

The Converting Furnace (C-furnace) of the Mitsubishi process has solely provided opportunities for producing blister copper continuously from molten matte. Continuous converting originates from the proven technology for controlling the behavior of magnetite in lime-ferrite slag of the CaO-FeOX-Cu2O system. Recent improvements in the C-furnace operation have included the slag controls reflecting the impact of minor oxides on magnetite behavior. Although previous investigations focused on magnetite behavior, sulfur has also affected the C-furnace operation because it is of practical importance to avoid the precipitation of gypsum from lime-ferrite slag and the separation of matte from blister copper. This paper will quantify the behavior of sulfur in C-furnace with respect to the gypsum formation and matte separation, and discuss better controls for C-furnace operation.

Jan 1, 2006

By M. Tangstad, H. Mølnäs, J. D. Steenkamp

"Temperature affects several aspects of pyrometallurgical systems, including thermodynamics and reaction kinetics. Reliability of temperature measurements in laboratory and plant applications is thus important from process, safety and financial perspectives. This case study briefly introduces different techniques utilized for temperature validation, and demonstrates temperature validation on laboratory scale utilizing the wire-bridge method. Pt/Ptl3Rh thermocouple hot junctions were constructed by mechanically connecting thermocouple wires through a pure metal bridge consisting of copper, gold, nickel or palladium wire. When heating the wire-bridge thermocouple alongside a regular Pt/Ptl3Rh thermocouple, temperature offsets were quantified as the wirebridge thermocouple short-circuited at the melting points of the pure metals. At the melting points of gold (1064°C) and palladium (1555°C), average measured temperature offsets were -2.1°C ± 2.3°C and 0.2°C ± 0.4°C, respectively. Results from the copper and nickel wire-bridges were inconclusive. The paper concludes with a discussion on the potential industrial applications of the technique.IntroductionThermocouples are probably the simplest of all temperature sensors, but are widely utilized due to simplicity, versatility and ability to handle a variety of experimental conditions and industrial applications. Additionally, thermocouples are often the only option in research laboratories requiring high temperature measurements, and a high level of reliability is usually required from thermodynamic, kinetic as well as safety points of view.The study presented here originated from a test program where the compatibility between different types of carbon-based refractory materials and industrial slag produced in silicomanganese furnaces were investigated on a laboratory scale utilizing the static crucible test[l]. Due to the nature of the silicomanganese production process, the compatibility tests were to be conducted at 1600CC[2]. Details of the experimental set-up utilized for the compatibility tests are discussed in the Experimental Set-up and Method Statement section later in this paper."

Jan 1, 2012

By Wilson Pascheto

This paper presents results of investigations performed as part of a Root-Cause-Failure-Analysis (RCFA) of a DC smelting furnace that was brick lined with MgO-based refractories. An unusual continuous contraction of the furnace hearth was identified during operation. Cracks in the refractories were envisaged after a major shutdown of the furnace. To determine the mechanism and causes of the unusual contraction behaviour of the furnace hearth, refractory samples were taken from the furnace at different locations and subjected to different analysis including Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), QEMSCAN and Electron Probe Micro Analysis (EPMA). Creep testing of refractories under different loads (ASTM C832) was also employed to evaluate the mechanical integrity of the used bricks in comparison with the new ones. Results of the various characterisation analyses revealed that there was an interaction between refractory bricks and molten material during furnace operation, which resulted in reduced creep resistance of the MgO-based refractories. This was verified by comparing creep performance of the used brick samples and new brick samples at different temperatures and applied stresses.

By Xinhua Wang, Xuefeng Liu, Die Yang, Lifeng Zhang, Wen Yang

"CSP thin slab continuous casters are well used in recent years. The control of heat transfer in the mold is very important because it is correlated with several slab defects. The mean heat flux of CSP mold was studied based on the plant production data of LCAK steel and weathering steel. The effect of various operation conditions on the heat flux was analyzed and discussed. The results showed that the heat flux was 2.1-2.6 MW/m2 on the wide face and 1.2-2.2 MW/m2 on the narrow face for the casting of LCAK steels. During the casting of weathering steel, the heat flus was mostly 2.05-2.5 MW/m2 on the wide face and was 1.1-1.8 MW/m2 on the narrow face. The heat flux depended largely on the casting speed. The heat flux on the wide face increased obviously with increasing casting speed when the casting speed was relatively low; however, at high speed, the heat flux increased slowly or kept constant. At low casting speed, the heat flux depended little on the superheat of the molten steel. The mean heat flux depended little on the level fluctuation at continuous casting mold.IntroductionCSP thin slab continuous casters are used more frequently in recent years for its low cost of construction and manufacturing. The structure of CSP mold is very different from that of conventional thick slab casting mold, inducing the difference of heat flux between them. There have been some studies about the heat flux of thick and medium slab casters [l, 2]. Heat transfer in the mold is very important for the solidification of molten steel because it is correlated with several slab defects such as slab break-out, longitudinal crack, and surface depression. Moreover, higher casting speed is desired to improve the productivity. The control of solidified shell is extremely important. The heat flux is largely influenced by several casting parameters such as the cooling intensity of the mold, the casting speed[3], the mold flux powder [3, 4] and the carbon content of steel as well [5]. The investigation on the heat flux and affecting parameters can help to understand the solidification of molten steel in the mold."

Jan 1, 2013

By Leonard J. Friedman

There have been considerable changes in systems, equipment design and materials used in the modern Sulfuric Acid process. Many of these will shape the metallurgical sulfuric acid plant for the year 2000 and beyond. Advances have come from all over the world, and include new scrubbing area designs, catalyst contacting devices, silicon stainless alloys for unlined acid systems, energy recovery from acid heat, stainless converters and heat exchangers, etc. This paper describes each of the process "advances" and presents a review and analysis indicating advantages, operating experience and limitations.

Jan 1, 1988

By Johan Sundström

Anhydrous DyC13 was prepared by dehydration of DyCl3?6H20 in a fluidized bed using both batch- wise and continuous feeding. A gas mixture with varied composition of argon and HCl was used. The productivity was high, reaching values of 0.25 mol H20/m2-st during the reaction step 6- 1 and 0.062 mol H2O/m2.s during the reaction step 1-0. The product was free from hydrolytic compounds, such as DyOCI, if control of inlet gas composition versus temperature was achieved. From the results of various experiments, some relations between HCI-concentration and temperature in order to avoid hydrolysis have been deduced. The fluidization process efficiency decreases drastically after the dehydration has proceeded down to about 10 mol% of remaining water. Therefore, in a final treatment the last traces of water were removed by slowly purging gas through a packed bed. The water content could thereby be reduced to less than 1 mol%.

Jan 1, 1997

By Junji Shibata

Extraction behavior of Ti(IV) and other metal ions, such as Fe(III), Fe(II), Cu(II), Zn(I1) and Co(I1) from acidic solutions like sulphuric acid and hydrochloric acid was studied in order to recover titanium from the waste solution in Ti02 production. Extractant used was tri-alkyl phosphine oxide whose trade name was Cyanex 923. Then, a study was made of the idea of simulating a countercurrent multistage extraction system, using the results of batch extraction. The simulation was camed out on extraction and saipping behavior for a Ti(1V)-H$O,-Cyanex 923 system. From the simulation result., the optimum operating condition of the system was considered.

Jan 1, 1994

By Gregor Mori

Niobium electrolysis has been performed in a NaCl-KCl-NaF-NbCls electrolyte. By means of electrolytic .refining the average valency of the niobium ions was determined as well as the crystallization behaviour. In electrowinning runs the influence of the main parameters such as temperature, RF (mole ratio F/Nb), chemical prereduction, niobium content of the melt and current density has been determined with respect to low specific energy consumption and high purity of the deposit.

Jan 1, 1995

By Russell James Hewertson

Since 1989 Air Products and Chemicals, Inc. has converted over 40 air fuel fired furnaces to oxy-fuel and air-oxy-fuel. Advances in burner design, flow control technology and operating experience have lead to improved performance with quicker melt times and lower costs. Metal recoveries are improved by faster melting and better furnace atmosphere control, allowing lower grade materials to be processed economically. The presentation will discuss the improvements made in recent years and review data from state of the art installations.

Jan 1, 2000

By Etsuro Shibata

For the treatment of huge amounts of the sulfur which is from the earth by both natural and man-made activities, a harmonized sulfur cycle was presented. The man-made sulfur cycle which includes sulfur circulation from oil, coal and ore was analyzed in detail based on the recent world sulfur trend. Then the man-made cycle was compared with the natural sulfur evolution such as volcano. Finally, the harmony in both natural and man-made sulfur cycles was discussed.

Jan 1, 2006