A new automated, safe, environmentally sustainable, and high extraction soft-rock underground mining method

SYNOPSIS Ore deposits are becoming more complex to mine as a result of the exhaustion of surface and other easily mined deposits. There is also increasing socio-political pressure to design more environmentally sound, sustainable, and safe mining practices. Wang and Ma designed a mining method for coal, similar to a modified drift and fill using a continuous miner to take sequential cuts (rooms) that are subsequently backfilled. The authors have modified the concept to make it more autonomous, safer, and less costly using highwall coal mining techniques, modified and adapted for underground applications. The method is more flexible than longwall mining and the percentage extraction would seem to be in the same range. In addition because of the backfilling, surface subsidence would not be a major issue and could be more effectively managed. Keywords: highwall mining, underground coal mining, backfilling, backfill face stability, continuous miner, safety.

Effect of pH, Anions and Acids on the Extraction of Zinc (II) from Aqueous media using Acetylacetone Solutions of Sulphamethoxazole

The challenge of heavy metal contaminations have been remediated to a certain level by the application of several methods of their extractions from aqueous media. Solvent extraction of zinc (II) ions from buffered aqueous solutions into acetylacetone solution of sulphamethoxazole as a function of pH and concentration of anionic substances and certain mineral acids were investigated in this work. The aqueous medium was prepared by dissolving 1.0995g of ZnSO4.7H2O in 250 ml volumetric flask to form 1000mg/L solution. 50mg/L working concentration was prepared from the 1000mg/L by dilution method. The organic phase is 0.5 M Sulfamethoxazole solution prepared by dissolving 12.664g of the salt in 100 ml acetylacetone. 2 ml each of aqueous and organic phases were taken with micro pipette and transferred into a set of 20 ml extraction bottle and the mixture was agitated mechanically for about 30 minutes. The mixture was allowed to settle and separate into two layers. 1 ml of the aqueous phase was taken, diluted and analysed for Zn (II) ions using atomic absorption spectrophotometer at a wavelength of 213.9. The results obtained on studying the effect of pH showed that Zn (II) ion was quantitatively extracted between pH of 7.0 to pH 8.0. The highest percentage extraction 85.37% was observed at pH 8.0 in acetylacetone solution of sulphamethoxazole. Increase in pH above 8.0 resulted in a steady decrease in the extraction of Zn (II). Studies on the effect of anions showed significant extractions which changes as the anions concentrations increased. All studies on mineral acids also showed significant extractions and increase in the concentrations of the acids affected the percentage extraction. Generally Zinc (II) ions can be extracted quantitatively in mild acids and anions concentrations when buffered from slightly acidic pH ranges of 6.0 to slightly alkaline pH values of 8.5.

Resorcin[4]arene Schiff base derivatives: Synthesis, characterization, and extraction studies

Novel 2,6-dihydroxyacetophenone[4]arene derivatives with an electron-withdrawing group at the ortho-position are developed. The 2,6-dihydroxyacetophenone[4]arene derivatives are condensed with benzylamine in chloroform to give the Schiff base derivatives of resorcin[4]arene. The acetyl group of the 2,6-dihydroxyacetophenone[4]arenes is condensed with primary amine groups to form imines. The multifunctional target molecules are purified and isolated in good yields. The Schiff base derivatives are characterized by elemental analysis, 1H and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and mass spectrometry. All the Schiff base compounds are successfully used for the extraction of toxic metals including Ni2+, Mn2+, Hg2+, Co2+, and Na+ using a liquid–liquid solvent extraction process. Among these tested metals, the percentage extraction of Hg2+ is the highest. As sodium dichromate has greater oxidative stability to transfer the HCr2O7− anion from an aqueous a protonated ligand solution, an anionic extraction study of dichromate is tested at various pH values.

Solvent Extraction of Copper (II) Ions Using Unmodified and Aromatic Amine Modified Red Onion Skin Extract

This study investigated the use of unmodified red onion skin extract (UROSE), aniline modified red onion skin extract (AmROSE) and 2-aminophenol modified red onion skin extract (APmROSE) for the extraction of copper (II) ions from aqueous media. The effect of pH, agitation time, ligand concentration and metal ion concentration on the percentage extraction were explored. The stoichiometric coefficients of the metal ions and the ligands (UROSE, AmROSE and APmROSE) in each extraction experiment were determined using slope analysis. The results revealed that the percentage extraction of copper (II) ions increased with increasing ligand concentration and agitation time and decreased with increasing initial concentration of copper (II) ions. The optimum pH for the extraction of copper (II) was found to be 6.77, 6.10 and 2.57 for UROSE, AmROSE and APmROSE respectively, while slope analysis showed that UROSE, AmROSE, and APmROSE ligands reacted with the metal ion in 1:1 molar ratio.

On the Extraction of Vanadium (V) by Alkanols: A comparative Study of 1-pentanol and 3-methyl-1-butanol Isomers as Extractants for Vanadium (V) Extraction from Hydrochloric Acid Solutions

<p>Further to the previous study on the extractive recovery of V(V) from HCl solution by some alkanols, the extraction of V(V) from HCl solutions by 1-pentanol and 3-methyl -1-butanol (isomers) dissolved in n-heptane were investigated in the present study, still propelled by the need to proffering viable alternatives to the scarce and relatively costly organophosphorous extractants, and also compare the extraction efficiency of straight- and branched-chain extractants. At the studied pH range (0.5-4.0) with 1-penttanol as extractant, the percentage V(V) extraction (extraction efficiency, E%) reached optimum E%= 40.0 at pH of 3.0 and for 3-methyl-1-butanol, optimum E% was 36.7 at pH 2.0. Increasing concentration of HCl at the studied range (1.0 – 6.0 mol L^-1) was found to have an appreciable effect on percentage V(V) extraction. With both extractants, E% peaked at 5.0 and 6.0 mol L^-1HCl with values 70.0 and 66.7% for 1-pentanol and 3-methyl-1-butanol respectively.</p><p>With increase in the concentration of extractants, both extractants produced a trend of increased/decreased in E% for V(V), suggesting the extraction of two different species. The optimal percentage extraction values were 70.0 and 66.7% observed at log [1-pentanol] = 0.86 mol L^-1 and log[3-methyl-1-butanol]=0.86 mol L^-1, in that order. The determined enthalpy change. for 1-pentanol and 3-methyl-1-butanol systems were -80.4/120 kJ mol^-1and -203.0/254.7 kJ mol^-1 respectively, indicating exothermic/endothermic extraction processes. The isomer 3- methyl -1-butanol gave a higher extraction efficiency after a three-stage extraction (E% = 92.5) than 1-pentanol (E% = 83.4). Recycling experiment revealed both to be recyclable. From slope analysis, analytical and spectra data, the extracted complexes have been formulated as VO₂Cl.nROH and (VO₂Cl)_m.nROH (where m&gt;&gt; n) at low and high concentrations of extractant, respectively. On the whole, 3-methyl-1-butanol was assessed as fairly better as an extractant for vanadium (V) at lower temperature experimental conditions. The effect of methyl branched-chain played an insignificant role on the extraction.</p>

Research on Separating Rubidium from Deep Potassium-Rich Old Brine by Solvent Extraction

A deep potassium-rich old brine in Hubei Province contains a large number of rubidium resource. Separation of rubidium is very difficult due to the similar physical and chemical properties of rubidium with the other coexisting alkali metals (potassium, sodium, and lithium). The process of extracting and separating Rb from the old brine with 4-tert-butyl-2-(α-methylbenzyl) phenol(t-BAMBP) as the extraction agent and sulfonated kerosene as diluents was systematically studied in this paper. The concentration of extraction agent, alkalinity of the old brine, phase ratio, the extracting time and other related factors were investigated. The optimal extraction conditions were obtained as follows: the concentration of t-BAMBP was 1.0mol/L, the concentration OH- was 0.6mol/L, the phase ratio was 3, the extraction time was 3 minutes. The percentage extraction of Rb could reach 91% for single-stage extraction, the separation coefficient of Rb and K reached up to 16.15. Sulfonated kerosene as diluent is non-toxic, high flash point, non-environmental pollution. A high extraction rate and separation factor for the development of rubidium resource of deep potassium-rich brine provided a reliable basis.

A Comparison Study on Microwave-Assisted Extraction of Catalpol from Rehmannia glutinosa Libosch with Conventional Methods

Catalpol, an iridoid glycoside, has been verified to be of neuroprotection and may be a potential agent for the treatment of neurodegenerative disease. The extraction technology of catalpol has been tested in this paper. We used different extraction methods including extraction at room temperature (ERT), heat reflux extraction, Soxhlet extraction, ultrasonic extraction and microwave-assisted extraction (MAE) to evaluat the percentage extraction of catapol fromRehmannia glutinosa Libosch.The extracts were analyzed by high performance liquid chromatography (HPLC). Methanol (100%, v/v) extracted high percentage extraction of catapol compared to ethanol (60%, v/v) which achieved the highest percentage extraction of catapol in different concentration of ethanol. The results showed that the percentage extraction of catalpol fromRehmannia glutinosa Liboschby MAE was more efficient in short time followed by ultrasonic extraction, Soxhlet extraction, heat reflux extraction and ERT methods. MAE has need of 4 min, whereas ultrasonic extraction, Soxhlet extraction, heat reflux extraction and ERT techniques require 70, 140, 180 min and 60 h respectively, to leach higher percentage extraction of catalpol. The time taken by MAE was nearly 18 times less than the ultrasonic extraction, 35 times less than Soxhlet extraction, 45 times less than heat reflux extraction and 900 times less than ERT for the highest percentage extraction of catalpol. The present results showed that the high extraction efficiency and considerable saving of time by MAE were more competent than the conventional extraction techniques.

Evaluation and Optimization of Downstream Process Parameters for Extraction of Betulinic Acid from the Bark ofZiziphus jujubaeL.

Present work investigated an apposite and efficient method for extraction of betulinic acid (BA) from the bark ofZiziphus jujubae. Various extraction methods like stirring extraction, soxhlet extraction, ultrasonic extraction, and microwave assisted extraction (MAE) were evaluated for increasing recovery percentage of BA. From the raffinate so obtained, BA was isolated. Thin layer chromatography (TLC) was used to analyze the extract and high performance liquid chromatography (HPLC) for quantification. The results revealed that the percentage extraction of BA fromZ. jujubaeby MAE was more proficient. As recovery percentage of BA by MAE technique turned out to be maximum, by using response surface methodology (RSM), three process parameters (pH, temperature, and time) were optimized by MAE and it was observed that the optimum parameters (pH 6.5, temp. 70.23°C, and time 3.5 min) gave the maximum recovery of BA (0.44% w/w). To validate the RSM model, experiments were performed and the highest recovery of BA was found to be 0.4% w/w which is ±0.04% to the predicted value. Henceforth the extraction efficiency and the substantial saving of time by MAE was more capable than the other extraction techniques.

Pengaruh Ion Kadmium(II) dan Nikel(II) pada Ekstraksi Ion Tembaga(II) dengan Ekstraktan 4-Benzoil -1-Fenil-3-Metil- 2- Pirazolin-5-On Menggunakan Emulsi Membran Cair

The effects of cadmium(II) and nickel(II) ions to copper(II) extraction using liquid membrane emulsion with 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-on (HPMBP) as an extractant was studied. The optimum condition forcopper(II) extraction were as follows: emulsification rate=2000 rpm, emulsification time=10 minutes, extractionrate=300 rpm, extraction time=15 minutes, concentration of mixed surfactant (span 80+span 20)=3%, volumeratio of membrane phase and internal phase=1:1, concentration of HPMBP=0.020 M, concentration of HCl=1M,volume ratio of emulsion and external phase=1:7. The result showed that the extraction of copper(II) by liquidmembrane emulsion with HPMBP as an extractant was selective to cadmium(II) and nickel(II) ions, relatively. Theresult also showed that in the extraction of 500 mg/l copper(II), the presence of 500 mg/l of nickel(II) was decreasingthe percentage of copper(II) extraction to be 83.73. While, the presence of 500 mg/l of cadmium(II) does notinfluence the percentage extraction of copper(II), relatively.

Recovery of Nickel and Iron from Lixivium of Nickel Laterite Ores

The joint technics on sodium jarosite process and solvent extraction technique for lixivium of nickel laterite ores has been investigated. The results indicate that a Fe2O3 product with Fe grade of 58.12% could be obtained by precipitation separation and roasting, the total recovery of iron reaches 94.87%.Under the conditions of extracting temperature for 30°C, phase ratio 1:1, blance time 10min, pH = 5.5, the percentage extraction rate of Ni reaches 99.04%. When the 3 mol/L H2SO4 solution was used as stripping agent, the stripping rate of Ni reaches 97.52%. The total recovery of nickel reaches 94.56%.