Direct Aqueous Mineral Carbonation of Waste Slate Using Ammonium Salt Solutions

Jo, Hwanju; Jo, Ho Young; Rha, Sunwon; Lee, Pyeong Koo

doi:10.3390/met5042413

Cited by 7 publications

(5 citation statements)

References 32 publications

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“…As-received red mud samples with residual water were dried at 105 • C in an oven for 48 h. The dried red mud was then mixed with solid NH 4 Cl (10:1 weight ratio, i.e., red mud sample with the addition of solid NH 4 Cl). A fixed weight ratio (10:1) was used in the present study because Jo et al [39] reported that the concentration of ammonium salt solutions had a slight effect on the alkaline earth metal leachability of waste material (i.e., waste slate). However, it should be noted that the weight ratio might affect the results of the present study.…”

Section: Methodsmentioning

confidence: 99%

Selective Leaching Trace Elements from Bauxite Residue (Red Mud) without and with Adding Solid NH4Cl Using Microwave Heating

Kim

Choi

2021

Metals

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Bauxite residue (red mud), which is an industrial byproduct, contains valuable trace elements. Solid NH4Cl was used as a chlorinating agent during the microwave heating of red mud to convert trace elements into soluble metal chloride. Red mud was heated using microwave ovens under various conditions (i.e., with the addition of solid NH4Cl and with a range of microwave output powers and microwave heating times). Leaching tests were then conducted using deionized (DI) water on the microwave-heated red mud to leach trace elements from red mud. V, Cr, and As were selectively leached from the microwave heated red mud slurry (30% water content), whereas Mn, Cu, Co, Ni, Zn, and Pb were selectively leached from the microwave-heated red mud with the addition of solid NH4Cl. The oxides of V, Cr, and As in red mud could be transformed into metal chlorides by chlorination, which are insoluble in water, or could be easily volatilized when red mud was microwave-heated in the presence of solid NH4Cl. On the other hand, the oxides of Mn, Cu, Co, Zn, Ni, and Pb in red mud could be heated rapidly by microwave irradiating, resulting in metal chlorides in the presence of solid NH4Cl. Those metal chlorides are relatively soluble in water, leading to higher leaching efficiency for microwave-heated red mud with the addition of solid NH4Cl. Experimental results suggest that trace elements from red mud can be selectively leached by microwave heating of red mud without or with the addition of solid NH4Cl.

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Section: Methodsmentioning

confidence: 99%

Selective Leaching Trace Elements from Bauxite Residue (Red Mud) without and with Adding Solid NH4Cl Using Microwave Heating

Kim

Choi

2021

Metals

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“…Among inorganic solvents, an ammonium chloride (NH 4 Cl) solution has been reported as an appropriate solvent to leach alkaline earth metals from industrial by‐products such as steel slag, waste concrete and coal fly ash for aqueous mineral carbonation. This aqueous mineral carbonation has none or a small amount of a base solution such as NaOH solution for adjusting the pH, required during carbonation processes to induce calcium carbonate precipitation …”

Section: Introductionmentioning

confidence: 99%

“…This aqueous mineral carbonation has none or a small amount of a base solution such as NaOH solution for adjusting the pH, required during carbonation processes to induce calcium carbonate precipitation. 14 Microwave-assisted leaching in metallurgy has been investigated to reduce the processing time. 15 Microwave energy is nonionizing electromagnetic radiation with frequencies in the range of 300 MHz to 300 GHz.…”

Section: Introductionmentioning

confidence: 99%

Calcium and sodium recovery from microwave‐pretreated red mud with added solid ammonium chloride

Kim

Choi

2019

J of Chemical Tech & Biotech

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BACKGROUND Many studies have used an NH4Cl solution as a solvent during microwave‐assisted metal leaching processes. However, in this study, solid NH4Cl instead of an NH4Cl solution was used as a chlorinating agent during the microwave pretreatment of red mud to induce a rapid temperature increase by minimizing heat loss by water. Red mud only and red mud–solid NH4Cl samples were pretreated by microwaves under various conditions. Leaching tests were then conducted on the microwave‐pretreated red mud only and red mud–solid NH4Cl samples using deionized (DI) water as a leaching solution. RESULTS The leached Ca and Na concentrations from the microwave‐pretreated red mud–solid NH4Cl samples were significantly higher than those from the microwave‐pretreated red mud only samples at the given test conditions. In contrast to the red mud only samples, the leached Ca and Na concentrations from the microwave‐pretreated red mud–solid NH4Cl samples increased with increasing microwave output power. The leached Ca and Na concentrations from the microwave‐pretreated red mud–solid NH4Cl samples at 5000 W were significantly higher than those from the microwave‐pretreated red mud–solid NH4Cl samples at 500 and 1100 W and from the non‐microwave‐pretreated red mud–solid NH4Cl samples. CONCLUSION Adding solid NH4Cl to the red mud during the microwave pretreatment process is effective to recover Ca and Na at a microwave output power of 5000 W. The leached solutions with elevated Ca and Na concentrations from the microwave‐pretreated red mud–solid NH4Cl samples at 5000 W can be used for aqueous mineral carbonation to sequester CO2. © 2019 Society of Chemical Industry

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“…Hence, the possibility of separating iron and sodium must necessarily be investigated to ensure that the restraining process can be conducted harmlessly. X-ray diffraction (XRD) [16] and scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) [17] analysis are performed to determine the mineral phase of sodium in iron powder and tailing. The findings can aid in reducing R and in the subsequent sodium separation after direct reduction and may be beneficial in reducing the sodium carbonate consumption of current alumina production processes.…”

Section: Introductionmentioning

confidence: 99%

Restraining Sodium Volatilization in the Ferric Bauxite Direct Reduction System

Wang

et al. 2016

Minerals

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Direct reduction is an emerging utilization technology of ferric bauxite. However, it requires much more sodium carbonate than ordinary bauxite does. The volatilization is one of the most significant parts of sodium carbonate consumption, as reported in previous studies. Based on the new direct reduction method for utilization of ferric bauxite, this paper has systematically investigated factors including heating temperature, heating time, and sodium carbonate dosage influencing sodium volatilization. For the purpose of reducing sodium volatilization, the Box-Benhken design was employed, and the possibility of separating iron and sodium after direct reduction was also investigated.

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Direct Aqueous Mineral Carbonation of Waste Slate Using Ammonium Salt Solutions

Cited by 7 publications

References 32 publications

Selective Leaching Trace Elements from Bauxite Residue (Red Mud) without and with Adding Solid NH4Cl Using Microwave Heating

Selective Leaching Trace Elements from Bauxite Residue (Red Mud) without and with Adding Solid NH4Cl Using Microwave Heating

Calcium and sodium recovery from microwave‐pretreated red mud with added solid ammonium chloride

Restraining Sodium Volatilization in the Ferric Bauxite Direct Reduction System

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