Preparation of α-Alumina from Coal Fly Ash by Sintering with Sulfuric Acid

2010 ◽  
Vol 113-116 ◽  
pp. 2039-2044 ◽  
Author(s):  
Wen Ning Mu ◽  
Yu Chun Zhai
Keyword(s):  
Sulfuric Acid ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
Acid Leaching ◽  
National Standards ◽  
Sintering Process ◽  
Optimal Parameters ◽  
Mass Ratio ◽  
Sulfuric Acid Leaching ◽  
Sintering Time

A technology was studied to prepare -alumina from fly ash, and the integrated process flow including sintering with sulfuric acid, leaching, recrystallization, calcination was established in this paper. The influences including the particle size of fly ash, sintering temperature, sintering time and the mass ratio of sulfuric acid to fly ash on the extraction ratio of alumina were investigated and discussed during sintering process, and the optimal parameters were determined. The product of -alumina was examined by chemical analysis, XRD and SEM, and the results show that α-alumina reach the national standards.

Extraction of Aluminum from Coal Fly Ash Using Pressurized Sulfuric Acid Leaching with Emphasis on Optimization and Mechanism

JOM ◽  
2021 ◽  
Author(s):  
Peng Wang ◽  
Huiyong Liu ◽  
Fangyan Zheng ◽  
Yue Liu ◽  
Ge Kuang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Fly Ash ◽  
Coal Fly Ash ◽  
Acid Leaching ◽  
Sulfuric Acid Leaching

scholarly journals Investigation on the Effect of Roasting and Leaching Parameters on Recovery of Gallium from Solid Waste Coal Fly Ash

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1251 ◽  
Author(s):  
Jing Huang ◽  
Yingbin Wang ◽  
Guanxuan Zhou ◽  
Yu Gu
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Acid Leaching ◽  
Cost Effective ◽  
Mass Ratio ◽  
Leaching Process ◽  
Cost Effective Method ◽  
Roasting Temperature ◽  
Leaching Parameters ◽  
Roasting Time

Coal fly ash (CFA) provides important resources of gallium, which is regarded as an irreplaceable material in many technologies. A prospective roasting reagent assisted acid leaching process was proposed for the purpose of extracting gallium. The extraction efficiency of gallium by NaF (sodium fluoride) roasting followed by HNO3 (nitric acid) leaching process was demonstrated. The effect of roasting temperature, roasting time, the NaF-CFA mass ratio, acid leaching temperature, acid leaching time, and acid concentration were investigated. The results revealed that under optimal conditions (roasting temperature of 800 °C, roasting time of 10 min, acid leaching in 2 mol/L HNO3 for 1 h, and the NaF-CFA mass ratio of 0.75:1), 94% of gallium was extracted. Compared to previous studies, the process is a cost-effective method which can greatly shorten reaction time. It can reduce environmental pollution as it requires fewer acid reagents with low concentration and additives. It is expected to provide a method for the extraction of gallium from CFA.

scholarly journals Study on Ultrasonically-Enhanced Sulfuric Acid Leaching of Nickel from Nickel-Containing Residue

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 810
Author(s):  
Zhanyong Guo ◽  
Ping Guo ◽  
Guang Su ◽  
Fachuang Li
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Ultrasonic Waves ◽  
Sulfuric Acid Leaching ◽  
Solid Product ◽  
Leaching Process ◽  
Diffusion Controlled ◽  
Extraction Degree ◽  
Ultrasonic Conditions ◽  
Complex Nickel

In this paper, nickel-containing residue, a typical solid waste produced in the battery production process, was used to study the cavitation characteristics of ultrasonic waves in a liquid–solid reaction. The ultrasonically-enhanced leaching technology for multicomponent and complex nickel-containing residue was studied through systematic ultrasonic-conventional comparative experiments. An ultrasonic leaching kinetics model was established which provided reliable technological guidance and basic theory for the comprehensive utilization of nickel-containing residue. In the study, it was found that ultrasonically-enhanced leaching for 40 min obtained the same result as conventional leaching for 80 min, and the Ni extraction degree reached more than 95%. According to the kinetic fitting of the leaching process, it was found that the sulfuric acid leaching process belonged to the diffusion-controlled model of solid product layers under conventional and ultrasonic conditions, and the activation energy of the reaction was Ea1 = 17.74 kJ/mol and Ea2 = 5.04 kJ/mol, respectively.

Removal of Fe(III) from sulfuric acid leaching solution of phosphate ores with bisphosphonic acids

2021 ◽  
pp. 105799
Author(s):  
Chengjin Xu ◽  
Ling Li ◽  
Miaomiao Zhang ◽  
Xiao Meng ◽  
Xiujing Peng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Sulfuric Acid Leaching ◽  
Leaching Solution ◽  
Bisphosphonic Acids ◽  
Phosphate Ores

Sulfuric Acid Leaching of Bangka Indonesia Ilmenite Ore and Ilmenite Decomposed by NaOH

2013 ◽  
Vol 789 ◽  
pp. 522-530 ◽  
Author(s):  
Latifa Hanum Lalasari ◽  
Rudi Subagja ◽  
Akhmad Herman Yuwono ◽  
Florentinus Firdiyono ◽  
Sri Harjanto ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Sulfuric Acid ◽  
Solvent Extraction ◽  
Acid Leaching ◽  
Raw Material ◽  
Key Factors ◽  
Sulfuric Acid Leaching ◽  
Acid Environment

lmenite (FeO.TiO2) ore from Bangka island-Indonesia is a potential raw material for synthesizing titanium dioxide (TiO2), which can be used further as pigmen and photocatalyst. The fabrication of TiO2 particles from ilmenite can be carried out through the solvent extraction using sulfuric acid route. Therefore, the solubility of the ilmenite ore in sulfuric acid environment is one of the key factors to obtain the desired TiO2 particles. The current research is aimed at comparing the solubility of pristine Bangka ilmenite ore with that of precedingly decomposed by sodium hidroxide (NaOH) in pressurized and atmospheric reflux reactors. The dissolution of both precursors was carried out in those reactors under various temperatures of 75, 100, 125, 150 and 175°C. The results showed that the optimum dilution was achieved at 150°C. The obtained recovery of ilmenite was 88.8 % for the pressurized reactor and 75.5% for the atmospheric reflux reactor. The solubility of titanium (Ti) element increased steadily to reach a recovery of 68% at 150°C and decreased significantly afterwards. It was also found that the increase of iron (Fe) element solubility was proportional to the increase of processing temperatures.

scholarly journals Extraction of Ta and Nb from a Coltan Bearing Ore by Means of Ammonium Bifluoride Fluorination and Sulfuric Acid Leaching

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1392
Author(s):  
Alidor Shikika ◽  
Francois Zabene ◽  
Fabrice Muvundja ◽  
Mac C. Mugumaoderha ◽  
Julien L. Colaux ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Environmental Benefits ◽  
Process Conditions ◽  
Sulfuric Acid Leaching ◽  
Mechanical Agitation ◽  
Ammonium Bifluoride ◽  
Novel Approach ◽  
Pre Treatment ◽  
Subsequent Acid

A novel approach for Ta and Nb extraction consisting of the pre-treatment of a coltan-bearing ore with an ammonium bifluoride sub-molten salt and subsequent acid leaching has been studied. The effects from ore granulometry, ammonium bifluoride (ABF) to ore mass ratio, temperature and duration of fluorination on the degree of Ta and Nb extraction were examined. The ABF to ore ratio and process temperature were found to have the most pronounced impact on extraction efficiency. The following optimal process conditions were determined: ore granulometric fraction (−75 + 45 µm), ABF-ore (5/1), fluorination temperature (200 °C) and fluorination time (2.5 h). Maintaining these parameters enabled about 94% of Ta and 95% of Nb to be brought into solution during the sulfuric-acid-leaching stage. A comparison of the proposed method with previously reported studies suggests that due to the effects of mechanical agitation and the recirculation of the HF-containing gaseous phase back into the process, the dosage rate of ABF at the fluorination stage could be reduced significantly without sacrificing the overall recovery of Ta and Nb. In such a way, the approach could offer added environmental benefits since release of fluoride-containing effluents into the environment could be limited.

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