An Investigation into the Alkali Metals Removal from Zn-Bearing Dust Pellets in Direct Reduction

JOM ◽  
2022 ◽  
Author(s):  
Dingzheng Wang ◽  
Deqing Zhu ◽  
Jian Pan ◽  
Zhengqi Guo ◽  
Congcong Yang ◽  
...  
Keyword(s):  
Alkali Metals ◽  
Direct Reduction ◽  
Metals Removal

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

ON THE PROCESSING OF HEMATITE RAW MATERIALS AT THE KRYVOROZHSK MINING AND PROCESSING PLANT OF OXIDIZED ORE ON TECHNOLOGY OF DIRECT RECOVERY ITmk3

2018 ◽  
pp. 32-37
Author(s):  
P.I. Loboda ◽  
Younes Razaz ◽  
S. Grishchenko
Keyword(s):  
Magnetic Properties ◽  
Cast Iron ◽  
Iron Content ◽  
Raw Materials ◽  
Direct Reduction ◽  
Processing Plant ◽  
High Iron Content ◽  
High Iron ◽  
Direct Restoration ◽  
First Time

Purpose. To substantiate the efficiency of processing hematite raw materials at the Krivoy Rog Mining and Processing Plant of Oxidized Ores using the direct reduction technology itmk3®. Metodology. Analysis of the results of the itmk3® direct restoration technology developed by Kobe Steel Ltd., Japan and Hares Engineering GmbX, Austria, with a view to using it to process Krivbass hematite ores into granulated iron (so-called “nuggets”). Findings. The involvement in the production of hematite ores (oxidized quartzite) of Krivbass with high iron content, but with low magnetic properties for their processing into granular cast iron is grounded. Originality. The use of itmk3® direct reduction technology from Kobe Steel Ltd., Japan and Hares Engineering GmbH, Austria for the processing of Krivbass hematite ores into granular cast iron is justified for the first time. Practical value. The efficiency of the use of hematite ores (oxidized quartzite) has been substantiated, which can significantly reduce the costs in the mining cycle for the economical production of metallurgical products.

Metals Related to Radionuclides and Heavy Metals Removal Using Photosynthetic Bacteria Immobilized Recovery Type Porous Ceramic

2010 ◽  
Vol 46 (3) ◽  
pp. 119-127 ◽  
Author(s):  
KEN SASAKI ◽  
CHIHIRO HARA ◽  
KENJI TAKENO ◽  
HIROSHI OKUHATA ◽  
HITOSHI MIYASAKA
Keyword(s):  
Heavy Metals ◽  
Photosynthetic Bacteria ◽  
Porous Ceramic ◽  
Heavy Metals Removal ◽  
Metals Removal

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

Direct Reduction of Heavy Nonferrous Metals from Sulfide Compounds

2020 ◽  
Vol 61 (6) ◽  
pp. 601-607
Author(s):  
V. S. Chekushin ◽  
N. V. Oleynikova ◽  
S. P. Baksheev ◽  
A. V. Dontsov
Keyword(s):  
Direct Reduction ◽  
Nonferrous Metals ◽  
Heavy Nonferrous Metals
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