Pressurized Reactor Systems Research Articles

Pressure leaching of chalcopyrite with oxalic acid and hydrogen peroxide

This study investigated the dissolution behavior of metals from chalcopyrite concentrate in a pressure reactor system in the presence of hydrogen peroxide by oxalic acid leaching. The fact that the compounds formed by copper and iron with oxalic acid had different dissolution coefficients showed that metals could be selectively extracted based on the leaching temperature. The effects of various leaching parameters on metal extraction in the autoclave system were investigated at different H2O2 concentrations (1–5 M), H2C2O4 concentrations (25–125 g/L), leaching temperatures (318–443 K) and leaching times (15–180 min). While iron and copper extraction as a result of 180 min of leaching with 5 M H2O2, 318 K and 100 g/L H2C2O4 was respectively 90.6% and 1.73%, 88.5% of copper and 2.11% of iron could be extracted as a result of 180 min of leaching with 3 M H2O2, 443 K and 100 g/L H2C2O4. The reversal of the copper and iron extraction dissolution behavior started after the leaching temperature of 378 K. In the XRD analysis of leach residues obtained at low leaching temperatures, CuC2O4 peaks were dominant, while at high temperature conditions, Fe2O3 peaks were dominant.

Fluidized bed reactor design study for pressurized chemical looping combustion of natural gas

Chemical looping combustion (CLC) is considered a viable option for efficient power production with inherent carbon sequestration through an unmixed combustion process. Pressurized reactor systems promise the potential for increased efficiency compared to atmospheric processes because gas turbine technology can be used in a combined cycle to achieve high electric efficiency, comparable to GTCC plants with up to 60%el. A design study was conducted to investigate the potential of pressurized chemical looping combustion of natural gas for power generation, as well as its limitations. Basic design calculations have been carried out based on fluidization engineering methods and a practical process configuration has been evaluated based on mass- and energy balances. It turns out that a high gas turbine single cycle efficiency (>14%el) can only be reached if the CLC air reactor is operated at high temperature levels (>1000°C). An optimal range of operating conditions was identified for operation of a pressurized CLC plant and design considerations for a Dual Circulating Fluidized Bed reactor system are reported. Accordingly, also the fluidization gas (steam) demand for loop seals turns out to be relatively increased for pressurized systems. Based on the results of the present work, a net efficiency of up to 40.34%el can be expected for power generation from pressurized CLC, which is low compared to standard GTCC technology with and without CO2 capture measures implemented. The reasons are the limitation of reactor/turbine inlet temperature, higher relative pressure drop of CLC systems compared to conventional turbine combustion chambers, and the required loop seal fluidization steam.

Optimization of the leaching conditions of chalcopyrite concentrate using ammonium persulfate in an autoclave system

In this study, the leaching conditions of chalcopyrite concentrate with ammonium persulfate in a pressure reactor system were optimized using a central composite design (CCD). During decomposition of ammonium persulfate, the active oxygen formed can provide a high oxidation potential, acidic medium, and high pressure in a closed vessel for the direct leaching of chalcopyrite, which is a major advantage of this process over other leaching processes. The optimization criteria were defined to maximize copper extraction while minimizing iron extraction. The optimal leaching conditions were determined to be an ammonium persulfate concentration of 210 g/L, a leaching temperature of 388 K, and a reactor fullness ratio of 0.43; experiments were performed together with constant parameters including a leaching time of 180 min, stirring speed of 500 rpm, and liquid/solution ratio of 11 g/L. Under the optimal conditions, the recovery of Cu and Fe was 57.04% and 14.71%, respectively. The proposed quadratic model is in good agreement with the experimental data, exhibiting high correlation coefficients (R2) for the responses of both metals.

Sometimes the reason for demanding the quality and reliability of a Parr Pressure Reactor System is rather transparent.

RETURN TO ISSUEPREVAdvertisementNEXTSometimes the reason for demanding the quality and reliability of a Parr Pressure Reactor System is rather transparent.Cite this: Chem. Eng. News 2014, 92, 14, 16Publication Date (Print):April 7, 2014Publication History Published online31 March 2015Published inissue 7 April 2014https://doi.org/10.1021/cen-09214-ad08Copyright © 2014 Chemical & Engineering NewsArticle Views10Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1020 KB) SUBJECTS:Quality management Get e-Alerts

A research on the Extraction of Metals from Küre Chalcopyrite Concentrate in the Pressure Reactor System

A research on the Extraction of Metals from Küre Chalcopyrite Concentrate in the Pressure Reactor System

TEMPO-controlled radical suspension polymerization of poly(styrene)-block-poly(styrene-co-acrylonitrile) and poly(styrene)-block-poly(styrene-co-butyl methacrylate)

Suspension polymerization expands the study of controlled radical polymerization to high conversions and is known as a method to synthesize polymers with high molecular weights. The radical block copolymerizations of styrene (S) and acrylonitrile (AN) or butyl methacrylate (BUMA) controlled by 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) was performed in an oil/water pressure reactor system at a temperature of 125°C. TEMPO-terminated styrene homopolymer was employed as macroinitiator. The systems were examined by varying the composition of the monomer mixture at a constant reaction time, as well as by varying the reaction time for a characteristic monomer composition to get all of the possible conversion range. The solubility effects of acrylonitrile in the suspension medium were considered. Furthermore, the yield of the reaction was improved through initiator addition by taking control of the reaction. The polymerizations could proceed under control up to a conversion of 80–90%. By using the copolymerization equations, the solubility of pure acrylonitrile in the suspension medium could be calculated and was found to be 8 wt.-%.

Growth and Characterization of Ga0.47In0.53As Films on InP Substrates Using Triethylgallium, Triethylindium, and Arsine

Lattice matched epitaxial layers of on substrates are of current interest in a number of device applications. In this paper, we report on the growth of such epitaxial layers using organometallic chemical vapor deposition with triethylgallium (TEG), triethylindium (TEI), and arsine for the reactant species. A conventional, atmospheric pressure reactor system was used for these experiments. The depletion reaction between TEI and arsine has been modeled and a theory predicting the epitaxial layer composition as a function of the reactant pressures at the inlet has been developed, based on this model. The inclusion of an in situ substrate etching step has been found to significantly improve the surface morphology of the grown layer and resulted in mirror‐like surfaces. The effect of lattice mismatch is shown to be much worse for layers in tension than for layers in compression.