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.

scholarly journals Leaching of Manganese from Marine Nodules at Room Temperature with the Use of Sulfuric Acid and the Addition of Tailings

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 289 ◽  
Author(s):  
Norman Toro ◽  
Manuel Saldaña ◽  
Jonathan Castillo ◽  
Freddy Higuera ◽  
Roxana Acosta
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Room Temperature ◽  
Sulfuric Acid Concentration ◽  
Future Research ◽  
Independent Variables ◽  
Series Of Experiments ◽  
Optimization Methodology ◽  
Cost Efficient

Based on the results obtained from a previous study investigating the dissolution of Mn from marine nodules with the use of sulfuric acid and foundry slag, a second series of experiments was carried out using tailings produced from slag flotation. The proposed approach takes advantage of the Fe present in magnetite contained in these tailings and is believed to be cost-efficient. The surface optimization methodology was used to evaluate the independent variables of time, particle size, and sulfuric acid concentration in the Mn solution. Other tests evaluated the effect of agitation speed and the MnO2/Fe2O3 ratio in an acid medium. The highest Mn extraction rate of 77% was obtained with an MnO2/Fe2O3 ratio of 1/2 concentration of 1 mol/L of H2SO4, particle size of −47 + 38 μm, and 40 min of leaching. It is concluded that higher rates of Mn extraction were obtained when tailings instead of slag were used, while future research needs to focus on determination of the optimum Fe2O3/MnO2 ratio to improve dissolution of Mn from marine nodules.

scholarly journals PEMANFAATAN LIMBAH BATANG JAGUNG SEBAGAI ADSORBEN ALTERNATIF PADA PENGURANGAN KADAR KLORIN DALAM AIR OLAHAN (TREATED WATER)

2013 ◽  
Vol 2 (2) ◽  
pp. 1-5
Author(s):  
Fatimah Rahmayani ◽  
Siswarni MZ
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Environmental Pollution ◽  
Acid Concentration ◽  
Iodine Value ◽  
Agricultural Waste ◽  
Sulfuric Acid Concentration ◽  
Value Added ◽  
Treated Water ◽  
High Cellulose

Various result of agricultural waste that contain high cellulose can be used as an alternative adsorbent. One of them was derived from dried corn stalks which traditionally burnt after harvest that lead to environmental pollution. It is necessary to produce the value-added materials from corn stalks waste as an alternative adsorbent to reduce the level of chlorine in treated water. This process was performed by using various level of sulfuric acid concentration 1%, 3% and 5%, particles size 50 and 70 mesh in 105 oC with adsorbtion time 30, 60 and 90 minutes. The most favorable activation result was obtained at 5% concentration, with particle size 70 mesh, adsorbtion time 90 minutes and the iodine value was 482 mg/l with level of adsorbed chlorine was 96,08%. Based on this findings, we concluded that the corn stalks waste can be used as an alternative adsorbent in reducing the level of chlorine in treated water.

scholarly journals Uranium removal from tin smelter slag by bisulfate fusion and acidic leaching

Metalurgi ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 13
Author(s):  
Erik Prasetyo Prasetyo ◽  
Sonia Saraswati Meiliastri ◽  
Kurnia Trinopiawan ◽  
Yayat Iman Supriyatna ◽  
Fathan Bahfie ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Pulp Density ◽  
Molar Ratio ◽  
Hydrogen Sulfate ◽  
Fusion Temperature ◽  
Refractory Elements ◽  
Potassium Hydrogen ◽  
Direct Leaching

Slag as secondary product (waste) of tin smelter still contains not only valuable elements e.g. Ti, Nb, Ta, Zr, Hf and rare earth elements, but also radioactives such as Th and U, wich are accumulated in the slag phase during the smelting. Due to valuable element content, the slag becomes major of interest in mineral processing industries, hence the slag needs to be decontaminated before it could be processed further.Common approach to reduce U content from the slag using leaching process is considered ineffective due to association of U with refractory elements e.g. Si and Ti in the slag. To break down the refractory phases, the fusion approach by using fusing agent is required in order to release U so that they could be leached out using mild lixiviant.In this research, potassium hydrogen sulfate (KHSO4) and sulfuric acid was used as fusing agent and lixiviant, respectively. The parameters studied includes molar ratio between fusing agent and refractory elements in slag, fusion temperature, fusion time, sulfuric acid concentration in lixiviant and pulp density during leaching stage. The studies so far demonstrated that optimum condition in U removal occurred at fusion temperature 400 °C, fusion time 2 hours, molar ratio of potassium hydrogen sulfate to tin slag 5, sulfuric acid concentration 2 M and pulp density 15 ml/gr. The maximum recovery of U was 85.6%, which was significant compared to the results using direct leaching without fusion (0.1%).

scholarly journals Statistical Study for Leaching of Covellite in a Chloride Media

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 477
Author(s):  
Kevin Pérez ◽  
Norman Toro ◽  
Manuel Saldaña ◽  
Eleazar Salinas-Rodríguez ◽  
Pedro Robles ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Statistical Study ◽  
Sulfuric Acid Concentration ◽  
Chloride Concentration ◽  
Quadratic Model ◽  
Copper Extraction ◽  
Optimization Methodology ◽  
Composite Face ◽  
Central Composite

Covellite is a secondary copper sulfide, and it is not abundant. There are few investigations on this mineral in spite of it being formed during the leaching of chalcocite or digenite; the other investigations on covellite are with the use of mineraloids, copper concentrates, and synthetic covellite. The present investigation applied the surface optimization methodology using a central composite face design to evaluate the effect of leaching time, chloride concentration, and sulfuric acid concentration on the level of copper extraction from covellite (84.3% of purity). Copper is dissolved from a sample of pure covellite without the application of temperature or pressure; the importance of its purity is that the behavior of the parameters is analyzed, isolating the impurities that affect leaching. The chloride came from NaCl, and it was effectuated in a size range from –150 to +106 μm. An ANOVA indicated that the leaching time and chloride concentration have the most significant influence, while the copper extraction was independent of sulfuric acid concentration. The experimental data were described by a highly representative quadratic model obtained by linear regression (R2 = 0.99).

scholarly journals Leaching Chalcopyrite Concentrate with Oxygen and Sulfuric Acid Using a Low-Pressure Reactor

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 189 ◽  
Author(s):  
Josué Cháidez ◽  
José Parga ◽  
Jesús Valenzuela ◽  
Raúl Carrillo ◽  
Isaías Almaguer
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Oxygen Pressure ◽  
Batch Reactor ◽  
Sulfuric Acid Concentration ◽  
Low Pressure ◽  
Copper Extraction ◽  
Solid Concentration ◽  
Chalcopyrite Concentrate

This article presents a copper leaching process from chalcopyrite concentrates using a low-pressure reactor. The experiments were carried out in a 30 L batch reactor at an oxygen pressure of 1 kg/cm2 and solid concentration of 100 g/L. The temperature, particle size and initial acid concentration were varied based on a Taguchi L9 experimental design. The initial and final samples of the study were characterized by chemical analysis, X-ray diffraction and particle size distribution. The mass balance showed that 98% of copper was extracted from the chalcopyrite concentrate in 3 h under the following experimental conditions: 130 g/L of initial sulfuric acid concentration, temperature of 100 °C, oxygen pressure of 1 kg/cm2, solid concentration of 100 g/L and particle size of −105 + 75 μm. The ANOVA demonstrated that temperature had the greatest influence on copper extraction. The activation energy was 61.93 kJ/mol. The best fit to a linear correlation was the chemical reaction equation that controls the kinetics for the leaching copper from chalcopyrite. The images obtained by SEM showed evidence of shrinking in the core model with the formation of a porous elemental sulfur product layer.

Kinetics of Sulfuric Acid Leaching of Boron Slurry

2011 ◽  
Vol 366 ◽  
pp. 370-373
Author(s):  
Feng Gao ◽  
Xiang Guang Xu ◽  
Lei Li ◽  
Huai Yu Sun ◽  
Hong Xin Wang
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Reaction Temperature ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Product Layer ◽  
Leaching Kinetics ◽  
Diffusion Controlled ◽  
Reaction Activation Energy

The results of a leaching kinetics study of boron slurry with sulfuric acid were presented. Effect of ore particle size, reaction temperature, and acid concentration on magnesium dissolution rate were determined. The results shown that leaching of about 64.61% of magnesium was achieved using (-200+ 250) mesh ore particle size at a reaction temperature of 60°C for reaction time 100 min with 25% sulfuric acid concentration. Leaching kinetics indicated that diffusion through the product layer was the rate controlling process during the reaction. The reaction activation energy was determined to be about 3.35 kcal/mol, which was characteristic for a diffusion– controlled process.

Study on the Extraction of Arsenic in Destruction Residues of Arsenical Chemical Weapons

2014 ◽  
Vol 955-959 ◽  
pp. 2874-2879 ◽  
Author(s):  
Li Juan You ◽  
Ting Zhou ◽  
Xue Feng Wang ◽  
Yong Xu ◽  
Gang Rao ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Extraction Rate ◽  
Chemical Weapons ◽  
Single Factor ◽  
Solid Ratio ◽  
Orthogonal Experiments ◽  
Five Factors ◽  
Extraction Agent

In order to treat these arsenical residues produced when some arsenical chemical weapons were destroyed in Nanjing and recycle the arsenic, sulfuric acid was used as the extraction agent to extract the arsenic contained in the residuals, and single factor experiments and orthogonal experiments were carried out to study the effects of factors including concentration, liquid-to-solid ratio, temperature, shaking speed and time on the extraction effect. The results show that these five factors all have some effect on the arsenic extraction rate with the degree in the following order: Liquid-to-solid ratio> temperature> extraction agent concentration > time > shaking speed; when the sulfuric acid concentration is 1.2 mol/L and the liquid-to-solid ratio is 30, keeping the shaking speed at 200 r/min and extracting the residues at 40 °C for 2h, the arsenic extraction rate of the residues could reach up to 98.95%.

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.

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