Reduction-Roast Leaching of Low-Grade Pyrolusite Using Bagasse as a Reducing Agent

2013 ◽  
Vol 699 ◽  
pp. 28-33 ◽  
Author(s):  
Yun Fei Long ◽  
Jing Su ◽  
Xian Jia Ye ◽  
Hai Feng Su ◽  
Yan Xuan Wen
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Weight Ratio ◽  
Reducing Agent ◽  
Manganese Sulfate ◽  
Low Grade ◽  
Manganese Ore ◽  
Optimal Conditions ◽  
Roasting Temperature

Bagasse, a fibrous residue from sugarcane juice extraction, was used as a reducing agent to roast low-grade pyrolusite in N2. The roasted ore was further leached using sulfuric acid, to convert manganese oxide in the ore to manganese sulfate. The effects of weight ratio of bagasse to manganese ore, roasting temperature, roasting time, leaching temperature, leaching time, stirring speed and sulfuric acid concentration on the leaching recovery of manganese were investigated. Optimal conditions were determined to be a bagasse to manganese ore weight ratio of 0.8:10, roasting temperature of 500°C for 40 min, leaching stirring speed of 100 rpm, sulfuric acid concentration of 3 mol•L-1 and leaching temperature of 50°C for 40 min. The leaching recovery rate of manganese was up to 97.8% at the optimal conditions.

scholarly journals Implementation of sulfuric acid leaching for aluminum and iron removal for improvement of low-grade silica from quartz sand of Sukabumi, Indonesia

2021 ◽  
Vol 3 (6 (111)) ◽  
pp. 32-40
Author(s):  
Eko Sulistiyono ◽  
Murni Handayani ◽  
Agus Budi Prasetyo ◽  
Januar Irawan ◽  
Eni Febriana ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Acid Concentration ◽  
Quartz Sand ◽  
Raw Materials ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Low Grade ◽  
Sulfuric Acid Leaching ◽  
X Ray

Indonesia has very abundant reserves of silica, but progressive studies on the deposition of this material are very few, resulting in limited applications of silica. This work refers to the purification of silica from quartz sand originated from Sukabumi, Indonesia to obtain high-purity silica, which can be applied as important raw materials for special purposes. The aim of our research is to improve low-grade silica from quartz sand by removing impurities, especially aluminum and iron removal, using sulfuric acid leaching. In order to achieve the aim, the effect of reaction time and sulfuric acid concentration on the leaching process was investigated. The effectiveness of sulfuric acid for the impurities removal was observed. The chemical composition of the samples before and after leaching was studied using X-ray fluorescence. The mineralogical analysis of the starting materials and the products was conducted using X-ray diffraction. Microstructure analysis was performed using a scanning electron microscope, and EDS test was used to show the element composition at different points. The experimental results show that the optimum condition of the leaching process occurs at a reaction time of 5 hours with a sulfuric acid concentration of 10 N. The silica levels increase from 93.702 % to 96.438 %. Aluminum and iron impurities reduced from 4.691 % to 2.712 % and from 0.641 % to 0.094 %, respectively. At this optimum point, sulfuric acid is very effective to remove aluminum and iron impurities up to 42 % and 85 %, respectively. The results of this research can be a very significant opportunity to increase the value added of quartz sand from Sukabumi, which can enhance the quality of low-grade silica to provide better raw materials for glass industries.

Leaching of Niobium from Low-Grade Refractory Ore Using H2SO4 Roast System

2014 ◽  
Vol 997 ◽  
pp. 651-654 ◽  
Author(s):  
Biao Wu ◽  
He Shang ◽  
Wen Cheng Gao ◽  
Jian Kang Wen
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Weight Ratio ◽  
Dissolution Kinetics ◽  
Low Grade ◽  
Mass Ratio ◽  
Improved Method ◽  
Dilute Sulfuric Acid ◽  
Roasting Temperature ◽  
Kinetics Of

A new improved method is proposed for the leaching and extraction of niobium from a low-grade refractory niobium–tantalum ore.The ore was roasted and decomposed with concenrated H2SO4 then leached with dilute sulfuric acid. The effects of various factors, such as roasting temperature and time, acid to ore mass ratios,as well as particle size, on the dissolution kinetics of niobium were comprehensively investigated. The optimal conditions were particle size-38μm, roasting temperature 300°C,reacting time 2h and acid to ore mass ratio 1:1. The roasting residue reacted for 2 h with sulfuric acid in the ore/acid weight ratio of 3:1 at 90°C, the niobium was recoveried as high as 90.3%.

scholarly journals Release of reducing sugars from water hyacinth by thermochemical and enzymatic hydrolysis

2021 ◽  
Vol 6 (1) ◽  
pp. 156-164
Author(s):  
Jessica E. Guzmán-Pérez ◽  
◽  
Oscar J. Salinas-Luna ◽  
Ernesto Favela-Torres ◽  
Nohemi López-Ramírez ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
Acid Concentration ◽  
Water Hyacinth ◽  
Dry Matter ◽  
Eichhornia Crassipes ◽  
Reducing Sugars ◽  
Sulfuric Acid Concentration ◽  
Raw Material ◽  
Thermochemical Pretreatment

Water hyacinth (Eichhornia crassipes) is considered a pernicious herb in many parts of the world due to its rapid growth. However, for its high content of cellulose and hemicellulose, it could be considered as raw material to produce fermentable sugars. In this work, the effect of sulfuric acid concentration by thermochemical pretreatment and enzymatic hydrolysis on the release of sugars from water hyacinth was evaluated. Initially, the effect of the sulfuric acid concentration from 1.5 to 9% at 120 ºC was evaluated. With 1.5%, the release of reducing sugars was 160 milligrams of reducing sugars per gram of dry matter (mg red-sug/g dm). After the thermochemical pretreatment, the enzymatic hydrolysis with the cellulase complex (NS22086) allowed obtaining a reducing sugars concentration up to 317 mg red-sug/g dm. These thermochemical and enzymatic approaches to recover reducing sugars from water hyacinth is promising and should be evaluated for bioprocess using reducing sugars as the main source of carbon, such as bioethanol production.

scholarly journals Initial Investigation into the Leaching of Manganese from Nodules at Room Temperature with the Use of Sulfuric Acid and the Addition of Foundry Slag—Part I

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 565 ◽  
Author(s):  
Norman Toro ◽  
Nelson Herrera ◽  
Jonathan Castillo ◽  
Cynthia Torres ◽  
Rossana Sepúlveda
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Room Temperature ◽  
Sulfuric Acid Concentration ◽  
Extraction Rate ◽  
Molar Ratio ◽  
Independent Variables ◽  
Initial Investigation ◽  
Optimization Methodology

In this study, the surface optimization methodology was used to assess the effect of three independent variables—time, particle size and sulfuric acid concentration—on Mn extraction from marine nodules during leaching with H2SO4 in the presence of foundry slag. The effect of the MnO2/Fe ratio and particle size (MnO2) was also investigated. The maximum Mn extraction rate was obtained when a MnO2 to Fe molar ratio of 0.5, 1 M of H2SO4, −320 + 400 Tyler mesh (−47 + 38 μm) nodule particle size and a leaching time of 30 min were used.

Uranium Bioleaching from Low Grade Ore

2020 ◽  
Vol 989 ◽  
pp. 559-563
Author(s):  
Ashimkhan T. Kanayev ◽  
Khussain Valiyev ◽  
Aleksandr Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leach Solution ◽  
Low Grade ◽  
Bacterial Cells ◽  
Acid Mine

The goal of the present work was to perform bioleaching of uranium from low grade ore from Vostok deposit (Republic of Kazakhstan), which was previously subjected to long-term acid leaching. The ore initially contained from 0.15 to 0.20% of uranium in the form of uraninite, but ore samples used in the study contained about 0.05% of uranium, as it was exhausted during acid leaching, and uranium was partially leached. Representative samples of ore were processed in 1 m columns, leach solutions containing 5, 10, 20 g/L of sulfuric acid and bacterial cells (about 104) were percolated through the ore. Leaching was performed at ambient temperature for 70 days. In one of the percolators, the leaching was performed with leaching solution containing 10 g/L of H2SO4, cells of A. ferrooxidans, and 0.5 g/L of formaldehyde. Leaching with the solution containing 5, 10, and 20 g/L of sulfuric acid made it possible to extract 50, 53, and 58% of uranium. Addition of formaldehyde in leach solution led to the decrease in uranium extraction extent down to 37%. Thus, the results of the present work demonstrated that uranium ore exhausted during long-term acid leaching may be successfully subjected to bioleaching, that allows extracting residual quantities of uranium. Leaching rate of uranium from exhausted ore depended on both sulfuric acid concentration and microbial activity of bacteria isolated from acid mine drainage, formed on uranium deposit. In the same time, acid mine drainage may be used as a source of inoculate, to start bioleaching process.

scholarly journals Aerosol Surface Area Concentration: a Governing Factor for New Particle Formation in Beijing

2017 ◽  
Author(s):  
Runlong Cai ◽  
Dongsen Yang ◽  
Yueyun Fu ◽  
Xing Wang ◽  
Xiaoxiao Li ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Surface Area ◽  
Acid Concentration ◽  
Mass Concentration ◽  
Sulfuric Acid Concentration ◽  
Particle Formation ◽  
Atmospheric Environment ◽  
Geometric Standard Deviation ◽  
Growth Enhancement ◽  
New Particle Formation

Abstract. The predominating role of aerosol Fuchs surface area, AFuchs, in determining the occurrence of new particle formation (NPF) events in Beijing was elucidated in this study. Analysis was based on a field campaign from March 12th to April 6th, 2016, in Beijing, during which aerosol size distributions down to ~ 1 nm and sulfuric acid concentration were simultaneously monitored. The 26 days were classified into 11 typical NPF days, 2 undefined days, and 13 non-event days. A dimensionless factor, LΓ, characterizing the relative ratio of the coagulation scavenging rate over the condensational growth rate and predicting whether or not a NPF event would occur (Kuang et al., 2010), was applied. The three parameters determining LΓ are sulfuric acid concentration, the growth enhancement factor characterizing contribution of other gaseous precursors to particle growth, Γ, and AFuchs. Different from other atmospheric environment such as in Boulder and Hyytiälä, the variations of daily maximum sulfuric acid concentration and Γ in Beijing are in a narrow range with geometric standard deviations of 1.40 and 1.31, respectively. Positive correlation was found between estimated new particle formation rate, J1.5, and sulfuric acid concentration with a mean fitted exponent of 2.4. However, sulfuric acid concentration on NPF days is not significantly higher than that on non-event days. Instead, AFuchs varies greatly among days in Beijing with a geometric standard deviation of 2.56, while it is relatively stable at other locations such as Tecamac, Atlanta, and Boulder. Good correlation was found between AFuchs and LΓ in Beijing (R2 = 0.88). It appears that the abundance of gaseous precursors such as sulfuric acid in Beijing is high enough to have nucleation, however, it is AFuchs that determines the occurrence of NPF event in Beijing. 10 in 11 NPF events occurred when AFuchs is smaller than 200 μm2/cm3, and the NPF event was suppressed due to coagulation scavenging when AFuchs is larger than 200 μm2/cm3. Measured AFuchs is in good correlation with PM2.5 mass concentration (R2 = 0.85) since AFuchs in Beijing is mainly determined by particles in the size range of 50–500 nm that also contribute to PM2.5 mass concentration.

scholarly journals Wastewater Minimization in Indirect Electrochemical Synthesis of Phenylacetaldehyde

2002 ◽  
Vol 2 ◽  
pp. 48-52 ◽  
Author(s):  
Zhirong Sun ◽  
Xiang Hu ◽  
Ding Zhou
Keyword(s):  
Sulfuric Acid ◽  
Current Efficiency ◽  
Electrochemical Oxidation ◽  
Acid Concentration ◽  
Electrochemical Synthesis ◽  
Chemical Process ◽  
Sulfuric Acid Concentration ◽  
High Yield ◽  
High Current ◽  
High Current Efficiency

Wastewater minimization in phenylacetaldehyde production by using indirect electrochemical oxidation of phenylethane instead of the seriously polluting traditional chemical process is described in this paper. Results show that high current efficiency of Mn(III) and high yield of phenylacetaldehyde can be obtained at the same sulfuric acid concentration (60%). The electrolytic mediator can be recycled and there will be no waste discharged.

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