Mechanism of oxides reduction during bubbling of copper-smelting slags by CO–CO2 gas mixtures

2019 ◽  
pp. 13-22 ◽  
Author(s):  
A. A. Komkov ◽  
R. I. Kamkin
Keyword(s):  
Gaseous Phase ◽  
Kinetic Constant ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Copper Smelting ◽  
Oxide Reduction ◽  
Liquid Phases ◽  
Lead And Zinc ◽  
The Difference ◽  
Slag Reduction

The paper suggests a mechanism of simultaneous oxide reduction from multicomponent copper-smelting slags during their bubbling with CO–CO2 reducing mixtures and provides a numerical algorithm developed to implement this mechanism as a mathematical model. The first feature of the suggested mechanism is a statement that the total speed of the overall reduction process is determined by CO consumption during its interaction with oxygen ions formed in slag oxide dissociation. The second feature is a statement about equilibrium achieved between slag, alloy and gaseous phase according to the system oxidizing potential reached at every instant. The paper demonstrates a satisfactory agreement between calculated and experimental data obtained when reducing industrial coppersmelting slags at 1300 °С and СО/СО2 = 4, 6, 156, and using the first-degree kinetic equation regarding the difference between initial and equilibrium CO contents in the gaseous phase. A generalized kinetic constant of the multicomponent slag reduction reaction rate is calculated as k = 2.6·10–7, moles CO /(cm2 · sec·%) at 1300 °С. It is shown that during industrial multicomponent slag reduction, reduction speed of copper (I) oxide and magnetite are high and close to maximal ones as early as at the first minutes of slag bubbling with reducing gas. At the same time, for Fe(II), lead and zinc oxides they are low at the first minutes of the process, and increase gradually to reach their maximum, and then decrease again up to near-zero values as the supplied gas and melt come to equilibrium. Generally, oxide reduction speed naturally decreases with approaching to equilibrium between the initial gas and liquid phases, and this should be taken into account when designing continuous slag depletion processes.

Phase Transformation Behavior of Lead and Zinc in the High-Lead Slag Reduction Process

2021 ◽  
Vol 62 (2) ◽  
pp. 139-146
Author(s):  
Zhongtang Zhang ◽  
Weifeng Li ◽  
Jing Zhan ◽  
Gui Li ◽  
Zhenbo Zhao ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Reduction Process ◽  
Transformation Behavior ◽  
Phase Transformation Behavior ◽  
Lead And Zinc ◽  
Slag Reduction ◽  
High Lead

Insights into Heap Bioleaching at the Agglomerate-Scale

2017 ◽  
Vol 262 ◽  
pp. 185-188 ◽  
Author(s):  
Alison Cox ◽  
Christopher G. Bryan
Keyword(s):  
Interstitial Cell ◽  
Cell Concentration ◽  
Low Grade ◽  
Dissolved Metals ◽  
Copper Ore ◽  
Cell Numbers ◽  
Liquid Phases ◽  
Heap Bioleaching ◽  
Cell Concentrations ◽  
The Difference

Previous agglomerate-scale heap bioleaching studies have outlined the variations in cell numbers of the liquid and attached phases during colonisation of sterilised ore by a pure culture. In this study, a mixed mesophilic culture was used in agglomerate-scale columns containing non-sterilised low-grade copper ore. Over a six - month period, columns were harvested at various intervals to provide snapshots of the metal distribution and the quantity, location, and ecological variations of mineral-oxidizing microbes within the ore bed. The initial colonisation period in this experiment was dissimilar to previous work, as the indigenous community was retained within the ore-bed throughout acid agglomeration. The overall colonisation phase lasted for approximately 1,000 hours until cell concentrations stabilised. In each column, less than 0.05% of the total cells were found in the leachate, 15-20% in the interstitial phase and the remaining ~80% were attached to the mineral surface. Once cell numbers had stabilised, interstitial cell concentrations were approximately 2,000× greater than those in the leachate. This difference persisted for the duration of the experiment. Copper concentrations in the two liquid phases generally decreased over time, but were on average 50× higher in the interstitial phase. Iron concentrations were more stable, but again were 30× higher in the interstitial phase. This demonstrates that that the difference in cell concentration between the leachate and interstitial phases cannot be explained through diffusion gradients within the system as it is much greater than those observed for the dissolved metals. It also shows that the specific environmental conditions of the interstitial and attached cells are very different to those inferred through analysis of leachates alone.

Reduction Kinetics of Mill Scale Briquettes by Using A3 Fine Coal as a Reductant

2021 ◽  
Vol 21 (4) ◽  
pp. 2563-2567
Author(s):  
Nguyen Hoang Viet ◽  
Pham Ngoc Dieu Quynh ◽  
Nguyen Thi Hoang Oanh
Keyword(s):  
Reaction Rate ◽  
Reduction Process ◽  
Reduction Reaction ◽  
Reaction Rate Constant ◽  
Reduction Degree ◽  
Furnace Temperature ◽  
Time Duration ◽  
Mill Scale ◽  
Fine Coal ◽  
Kinetics Of

In this work, a mixture of mill scale with 5 wt% molasses as binder was pressed under pressure of 200 MPa to prepare briquettes. The reduction process was performed at the temperature of 1000, 1050, 1100, 1150 and 1200 °C in the bed of A3 fine coal as the reductant. The degree of reduction was evaluated at time duration of 15, 30, 45, 60, 90 and 150 minutes, after the furnace temperature reached the predetermined reduction temperature. The highest reduction degree is 94.7% at the reduction process temperature of 1200 °C. Reaction rate constant (k) increased from 4.63×10-4 to 5.03×10-3 min-1 when the temperature increased from 1000 to 1200 °C. The apparent activation energy of the reduction reaction (Ea) is about 95.6 kJ/mole.

scholarly journals Metal reduction by hydrogen from the B2O3-СaO-Ni(Zn, Pb, Cu)O melts thermodynamic modeling

2020 ◽  
Vol 61 (2) ◽  
pp. 145-151
Author(s):  
Alexander S. Vusikhis ◽  
◽  
Evgeny N. Selivanov ◽  
Stanislav N. Tyushnyakov ◽  
Viktor P. Chentsov ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Thermodynamic Modeling ◽  
Reduction Process ◽  
Reducing Agent ◽  
Metal Reduction ◽  
Oxide Melt ◽  
Reduction Processes ◽  
Lead And Zinc ◽  
Nickel Copper ◽  
Copper Lead

Thermodynamic modeling is used to describe the metal reduction processes by hydrogen from oxide melt in the B2O3-CaO- MeO (Me – Ni, Zn, Pb, Cu) system. Open systems approximation with periodic removal of metal particles and gases from the working melt composition is used in the method. By this work we present the thermodynamic modeling results of metal reduction processes (Ni, Cu, Pb, Zn) by Hydrogen. The reducible metals oxides content in the all melts was 3 mass %, and the mass ratio of B2O3/CaO was taken as 3 to be close to eutectic composition. The calculations made it possible to determine such parameters as oxide melt compositions and elements reduction degree depending on the induced gas quantity. of the Nickel, Copper, Lead and Zinc reduction process simulation from B2O3-CaO-MeO melts proved the reduction process by Hydrogen is similar to that which was earlier established when Carbon monoxide was used as the reducing agent. When Copper is reduced from CuO, the process occurs with intermediate Cu2O oxide formation (CuO → Cu2O → Cu). The Nickel (NiO → Ni), Lead (PbO → Pbs + Pbg) and Zinc (ZnO → Zng) recovery have been realized by one stage. The non-ferrous metals change content in the oxide melt and the degrees of its reduction depending on temperature and reducing agent quantity introduced are described by the second-order polynomial functional equations. Comparison of the Carbon monoxide and Hydrogen used for Nickel, Copper, Lead, and Zinc reducing to 90% metallization degree proved much less Hydrogen consumption.

scholarly journals Storage and Condition of Biomass Influence to Biosorption of Lead (II) and Zinc(II) by Saccharomyces cerevisiae Biomass

2010 ◽  
Vol 1 (1) ◽  
pp. 11-15
Author(s):  
Jasmidi Jasmidi ◽  
Eko Sugiharto ◽  
Mudjiran Mudjiran
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atomic Absorption ◽  
Room Temperature ◽  
Final Concentration ◽  
Biomass Storage ◽  
Lead And Zinc ◽  
The Difference ◽  
Biomass Influence ◽  
And Storage ◽  
Zinc Storage

The influence of length and condition of Biomass Storage on the biosorption of lead and zinc that present together in a solution by Saccharomyces cerevisiae biomass were studied. In this experiment, variables of length and condition of biomass storage were examined. Concentration of lead and zinc were determined by atomic absorption spectrophotometric (AAS) using air-acetilene as atomizing flame. Loading of lead and zinc on the biomass were determined as the difference between the initial and the final concentration of lead and zinc in the solution. Biosorption of lead and zinc were influenced by condition and storage of the biomass. Storage of biomass in the room temperature for one week cause an increasing uptake. Storage for longer period result in decrease of lead and zinc uptake. Storage of biomass in a freezer up to 2 weeks increased the uptake of lead, but did not influence the uptake of zinc. Storage for longer period decreased the uptake of both of lead and zinc. For all condition the uptake of lead higher than the uptake of zinc by Saccharomyces cerevisiae.

scholarly journals Evolution of mobile phases in cometary interiors

2020 ◽  
Vol 37 ◽  
Author(s):  
Christopher M. Fellows ◽  
Trevor C. Brown ◽  
Andrew Cooper ◽  
Marco Parigi
Keyword(s):  
Gaseous Phase ◽  
Kuiper Belt ◽  
Temporal Distribution ◽  
Cometary Nucleus ◽  
Dust Particles ◽  
Spatial And Temporal Distribution ◽  
Cometary Nuclei ◽  
Liquid Phases ◽  
Mobile Phases ◽  
Outer Crust

Abstract Beginning with loose aggregations of dust particles coated with heterogeneous ices under vacuum at Kuiper Belt temperatures, moving to Jupiter/Saturn distances and eventually to low-perihelion orbit, we consider the likely development of the gaseous phase within a cometary nucleus over the course of its lifetime. From the perspective of physical chemistry, we consider limits on the spatial and temporal distribution and composition of this gaseous phase. The implications of the gaseous phase for heat transfer and for the possible spatial and temporal development of liquid phases are calculated. We conclude that the likely temperatures, pressures, and compositions beneath the outer crust of typical cometary nuclei are such that fluidised phases can exist at significant depths and that these reservoirs give a coherent explanation for the high-intensity outbursts observed from cometary nuclei at large distances from perihelion.

An effective separation process of arsenic, lead, and zinc from high arsenic-containing copper smelting ashes by alkali leaching followed by sulfide precipitation

2020 ◽  
Vol 38 (11) ◽  
pp. 1214-1221
Author(s):  
Yuhui Zhang ◽  
Xiaoyan Feng ◽  
Bingjie Jin
Keyword(s):  
Separation Efficiency ◽  
Separation Process ◽  
Copper Smelting ◽  
Solid Ratio ◽  
Effective Separation ◽  
Lead And Zinc ◽  
Valuable Metals ◽  
Alkali Leaching ◽  
Sulfide Precipitation ◽  
High Arsenic

Separation of arsenic and valuable metals (Pb, Zn, Cu, Bi, Sn, In, Ag, Sb, etc.) is a core problem for effective utilization of high arsenic-containing copper smelting ashes (HACSA). This study developed an effective separation process of arsenic, lead, and zinc from HACSA via alkali leaching followed by sulfide precipitation. The separation behaviors and optimum conditions for alkali leaching of arsenic and sulfide precipitation of lead and zinc were established respectively as follows: NaOH concentration 3.81 M; temperature 80°C; time 90 minutes; liquid-to-solid ratio 4:1; agitation speed 450 revolutions/minute (r/min) and 2.0 times of theoretical quantity of sodium sulfide (Na2S); temperature 70°C; and time 60 minutes. The results indicated that the leaching rates of As, Pb, and Zn were 92.4%, 36.9% and 13.4%, respectively. More than 99% of lead and zinc were precipitated from the alkali leachate. The scanning electron microscopy/energy dispersive X-ray spectroscopy study confirmed that arsenic was dissolved from HACSA into the alkali leachate. Furthermore, lead and zinc were precipitated as sulfides from the alkali leachate. The proposed process was a good technique for separation of arsenic and enrichment of valuable metals for further centralized treatment separately. It provided high separation efficiency of arsenic and valuable metals, as well as low environmental pollution.

Sign in / Sign up

Export Citation Format

Share Document