scholarly journals Extraction of Titanium from Low-Grade Ore with Different Leaching Agents in Autoclave

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 497
Author(s):  
Mario H. Rodriguez ◽  
Gustavo D. Rosales ◽  
Eliana G. Pinna ◽  
Fernando M. Tunez ◽  
Norman Toro

The progressive depletion of primary sources to obtain metals has led to the search for alternative sources for their recovery. In the particular case of titanium, titaniferous sands are a viable option for obtaining this metal. This paper presents the results of the dissolution of titanium from titaniferous sands of Buenos Aires province (Argentina) in a laboratory autoclave (450 mL of capacity). The operating parameters studied were as follows: different acids (HF, H2SO4 and mixtures of these acids); leaching agent concentration, 5–20% v/v; temperature, 75–150 °C; time, 30–180 min; solid–liquid ratio, 0.9–3.6% w/v; stirring speed, 110–550 rpm. The obtained results indicate that the increase in the leaching agent(s) concentration, temperature and time of contact with the acid mixtures have a marked effect on the dissolution reaction of titanium. Optimal conditions to achieve 89% extraction of titanium were obtained by leaching at 123 °C, 330 rpm, 80 min and 1.8% w/v with a mixture of 15% HF (v/v) and 10% H2SO4 (v/v).

2014 ◽  
Vol 989-994 ◽  
pp. 1029-1032
Author(s):  
Yi Hua Jiang ◽  
Xin Long Jiang ◽  
Cheng Gang Cai

Optimization of total flavonoid extraction from Castor leaves using orthogonal test methodology with the factors of ethanol concentration, extraction temperature,extraction time,solid/liquid ratio on the yield of total flavonoids were investigated.The results showed that optimum extracting conditions of total flavonoids from castor leaves were as follows: adding 1:40 g·mL-1 of 30% alcohol and extracting for 30 min,extraction temperature 70°C. Under the optimal conditions, the maximal yield of flavonoids was of 1.81%.


2019 ◽  
Vol 11 (11) ◽  
pp. 1607-1611
Author(s):  
Lifeng Cheng ◽  
Shengwen Duan ◽  
Xiangyuan Feng ◽  
Ke Zheng ◽  
Qi Yang ◽  
...  

Pectin was extracted from Ramie [Boehmeria nivea (L.) Gaud] through ammonium oxalate extraction method. The influences of single factors (ammonium oxalate concentration, extraction time, solid–liquid ratio, and reaction temperature) on the yield of ramie pectin were studied. Orthogonal experiment was then performed to optimize the combination of the given conditions using pectin yield as the measuring indicator. Finally, the partial physicochemical properties of ramie pectin extracted in the optimal conditions were analyzed. Results showed that the optimal conditions for single-element experiment were 3.5 h (extraction time), 1:25 (solid–liquid ratio), 0.85% (concentration of ammonium oxalate) and 95 °C (extraction temperature), and that the optimal combination conditions for orthogonal experiment was 4 h, 1:30, 0.95% and 90 °C. The ramie pectin yield extracted in optimal conditions reached 15.81%, and its protein content, galacturonic acid content, and esterification degree were 0.659 mg/g, 49.92%, and 53.11%, respectively. Therefore, the proposed method was successfully applied to obtain ramie pectin and may provide scientific basis for improving the multi-utilization value of ramie.


2021 ◽  
Author(s):  
Zijing Zhou ◽  
Gaijuan Guo ◽  
Jinda Li ◽  
Hong Yan ◽  
Fen Li

Abstract This work screened out the optimal conditions for pretreatment of natural lignocellulose with inorganic salts and provided a simple, easy-to-operate, low-cost, clean and efficient pretreatment method for the efficient degradation of natural lignocellulose by strains. The results showed that the optimal pretreatment inorganic salt was FeCl2 with a concentration of 11%, pretreatment at 60°C for 48 h, and the solid-liquid ratio was 1:11 (g/mL). According to the characterization results, after pretreatment of FeCl2 solution, the smooth and dense structure of natural lignocellulose surface became rough and irregular, and surface fiber bundles showed spalling and fracture. Subsequently, the enzymes produced by solid-state fermentation of Aspergillus fumigatus were easier to enter the interior, which increased the contact area between materials and enzymes, and increased the amount of enzymatic loads, thereby improving the biodegradation effect.


2011 ◽  
Vol 236-238 ◽  
pp. 313-316
Author(s):  
Jun Ping Zhu ◽  
Jian Lu Ma ◽  
Xiao Chen Liu ◽  
Biao Zhang ◽  
Wei Jie Xu ◽  
...  

The object of this research is to investigate the factors influencing the hydrolysis of corn stover by dilute sulfuric acid and the types of sugars existed in hydrolysate. Experiment results showed that the optimal conditions were hydrolysis temperature 120°C, stover size 20-40 mesh, soak time 36h, reaction time 100 min, H2SO4concentration 1.5% and solid-liquid ratio 1:8. Sugars gained in the hydrolysate were xylose 3.0%, glucose 0.71%, mannose 0.12% and galactose 0.32% determined by capillary electrophoresis.


Author(s):  
Graciela Mateo Pietro

“Al rico nunca le ofrezcan / y al pobre jamás le falten”. Estos versos del Martín Fierro -obra maestra de la narrativa gauchesca argentina- remiten al Monte de Piedad de Buenos Aires: por un lado, esencializan la función social como institución proveedora de crédito a los sectores desamparados de la sociedad, y por otro permiten identificar a su autor, José Hernández, como miembro del Consejo de Administración de la entidad y tenaz defensor de su continuidad.El presente artículo estudia, a partir de los antecedentes del crédito pignoraticio y del rol desempeñado por los montepíos nativos a mediados del siglo XIX, el origen y la trayectoria del Monte de Piedad de Buenos Aires, destinado a aliviar las penurias de los sectores vulnerados, tanto nativos como inmigrantes, evitando que sean víctimas de la usura. En tal sentido y desde una perspectiva macro que dé cuenta de la situación económico- financiera del país y particularmente de la provincia de Buenos Aires, se privilegia el análisis micro de las distintas etapas de la historia de este entidad y de su función social; desde su fundación en 1877 dependiente del Banco de la Provincia de Buenos Aires, su incorporación una década después al patrimonio municipal y su conversión en 1904 en Banco Municipal de Préstamos. El punto de partida es un estado de la cuestión sobre el tema. Las fuentes primarias (Libros de Actas, Memorias y balances, Cartas orgánicas, Reglamentos de la institución, Diario de Sesiones de la Legislatura bonaerense y del Consejo Deliberante de la ciudad de Buenos Aires) así como algunas publicaciones periódicas de la época, resultan sustantivas para lograr el objetivo propuesto. “Never offer to the rich /and may the poor never lack” These verses by Martín Fierro -a masterpiece of Argentine gaucho narrative- represent the Monte de Piedad in Buenos Aires and its development. In a way, they essentialize the social function of this institution that provides credit to the underprivileged sectors of society. Besides, this affirmation allows to identify its author, José Hernández, as a member of the entity’s Board of Directors and a tenacious defender of its continuity.This article is based on the antecedents of the pledge credit and the role played by the native montepíos in the mid-19th century. Its focused in the study of the origin and trajectory of Monte de Piedad in Buenos Aires, as an institution which alleviated the hardships of the vulnerable sectors, both natives and immigrants, and prevented them from being victims of usury. Both macro and micro perspectives converge in this analysis. Firstly, the argentine economic and financial situation is taken into account to get to Buenos Aires’ province evaluation. Secondly, the history of this entity’s social function is examined since it was founded in 1877 (under the Bank of the Province of Buenos Aires), to its incorporation a decade later into the municipal patrimony and its conversion into the Municipal Bank of Loans, in 1904.The article starts with a bibliographic review of this particular subject. The proposed objective is achieved by analyzing diverse primary sources (Minutes Books, Memories and balances, Organic Letters, Institution Regulations, Journal of Sessions of the Buenos Aires Legislature and the Deliberative Council of the city of Buenos Aires) as well as the main periodical publications of the time.


2020 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Marouane Amine ◽  
Fatima Asafar ◽  
Latifa Bilali ◽  
Mehdi Nadifiyine

Phosphate is a very important natural resource in Morocco and one of the secondary resources of rare earth elements. Our study is particularly interested in Youssoufia phosphate, which contains 228.77 ppm of rare earth elements (ΣREEs). The purpose of our work is to study the influence of different parameters (acid concentration, solid/liquid ratio and temperature) in order to determine the optimal conditions for the leaching of rare earths. An experimental design (Doehlert matrix) has been drawn up to optimize the experimental conditions of the leaching. All tests were made with nitric acid at different concentrations varying between 1.5M and 4.5M with a solid/liquid ratio of 1/12 to 1/6; reaction temperature and duration are respectively 20°C to 80 °C and 60 min. The optimal conditions are obtained when using 69 °C as temperature, 4.1 M as acid concentration and 1/9 as solid/liquid ratio.


Author(s):  
Yerkebulan Raiymbekov ◽  
Uilesbek Besterekov ◽  
Perizat Abdurazova ◽  
Ulzhalgas Nazarbek ◽  
Galiya Kambarova ◽  
...  

Abstract Low grade phosphate-siliceous slates dump samples (about 11.98% P2O5) from Zhanatas deposit, Karatau basin, Kazakhstan were subjected to upgrading in the present study. The suggested upgrading route was to get rid of most of the inorganic carbonates via leaching using organic acids like acetic acid. The effect of leaching temperature, dissolution time, and solid/liquid ratio were studied as the main determental working parameters. It was concluded that a concentrate product containing about 21% P2O5 was produced after leaching with acetic acid at optimum conditions: 30 C0, 15 min, and 3:1 liquid/solid ratio. The calculated apparent activation energy of the leaching process showed that the process took place in the intra-diffusion region.


2013 ◽  
Vol 12 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Miroslav Ondrejovič ◽  
Daniela Chmelová ◽  
Tibor Maliar

Abstract Eleutherococcus senticosus is known as adaptogen with benefits in general health promotion. The aim of this study was to investigate the effect of major extraction parameters on extraction yield of antioxidants measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity. Secondly, content of total polyphenols was evaluated. Optimal conditions of the extraction were processed by response surface methodology. The independent variables of extraction were proposed as temperature, solid-liquid ratio and solvent composition. For the optimal antioxidant extraction, E. senticosus is suitable to extract by 23 % (v/v) aqueous ethanol at 70 °C in ratio 53 mL of extraction solvent per g of plant material. The optimal conditions calculated for the extraction of total polyphenols were very similar (70 °C, 22 % (v/v) aqueous ethanol) expect solid-liquid ratio which indicates need of increasing of solid-liquid ratio to 91 mL of extraction solvent per g of plant material


2011 ◽  
Vol 343-344 ◽  
pp. 826-831
Author(s):  
Lin Na Du ◽  
Jia Song ◽  
Ling Jun Meng ◽  
Jia Hui Lu ◽  
Qing Fan Meng ◽  
...  

An experimental mixture design coupled with data analysis by means of both response surface methodology(RSM) and artificial neural network(ANN) was applied to explore the optimum process parameters for adenosine extraction from cultured mycelium of Cordyceps militaris. With the extraction rate of adenosine as index, the critical factors selected for the investigation were extracting temperature, extracting time and solid-liquid radio. The results obtained by the application of ANN were more reliable since better statistical parameters were obtained. The optimum extraction procedure was as follow: extracting time 2.3 h, extracting temperature 48 °C, solid-liquid ratio 1:38 g⋅mL-1. Under the optimal conditions, the corresponding response value predicted for adenosine production was 4.59 mg g-1, which was confirmed by validation experiments.


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