Separation Flowsheet Research Articles

SHARP DISTILLATION FOR QUATERNARY SYSTEMS

Conditions of sharp distillation were considered for zeotropic quaternary system (two pairs of components are characterized by relative volatility close to 1) and systems with one (with minimum or maximum boiling point) and two (with minimum and maximum boiling point) binary azeotropes. Regions of compositions for which sharp distillation is effective (distillate and bottom flows don't contain common components) were determined on the basis of analyzing diagrams of unit manifolds of distribution coefficients (distribution coefficients of two components are higher than one, and those of another two components - lower than one). This kind of separation can be recommended if it doesn’t cause an increase in the number of apparatuses in the separation flowsheet. If the system contains azeotropes of saddle type that can generate separatric manifolds, the possibility and expedience of sharp separation decreases. The conclusions were confirmed by simulation of the distillation process in AspenPlus V.10.0 for real and industrially important quaternary systems: ethyl acetate - benzene - toluene - butyl acetate; acetone - methanol - ethanol - propanol-2; methyl acetate - methanol - acetic acid - acetic anhydride and cyclohexene - cyclohexane - cyclohexanone - phenol. Mathematical modeling was carried out using local compositions models Wilson and NRTL-HOC. The relative error of vapor-liquid equilibrium description is less than 4%. The vapor-liquid equilibrium was simulated, a phase diagram was constructed and analyzed, the parameters of sharp distillation column operation (the number of stages, the feed-stage and reflux ratio) were determined for all systems. The effectiveness of using sharp distillation for the system with phenol was confirmed for a wide range of compositions.

Effect of frictional grinding on ore characteristics and selectivity of magnetic separation

Frictional grinding was evaluated to improve the selectivity of two magnetite samples A and B in the magnetic separation process. Sample A containing 64.42% Fe was a magnetite concentrate upgraded from a low grade magnetite Ore, Sample B, containing 46.63% Fe, through an upgrading process involving 1-stage ball milling and 3-stage wet magnetic separation in a beneficiation plant. Frictional grinding was found extremely efficient in dispersing the grains in the agglomerates and on the surface, consequently improving the selectivity of the sample. A magnetite concentrate containing 66.22% Fe was produced from Sample A at an iron recovery of 96.86% by introducing a simple dry frictional grinding step prior to the magnetic separation process. The results have demonstrated that Sample A can be further upgraded even though it was processed through 3-stage magnetic separation. Given its beneficial effects, frictional grinding was further adopted in a multiple-stage flowsheet to upgrade both Samples A and B. A magnetite concentrate containing 68.75% Fe was produced from Sample A at an iron recovery of 97.23% through the multiple-stage wet frictional grinding-magnetic separation flowsheet. When the same flowsheet was applied to process Sample B, a concentrate of 69.97% Fe, higher than Sample A obtained by ball milling, was produced at an iron recovery of 86.44%.

Radiochemical characterization and decontamination of rare-earth-element concentrate recovered from uranium leach liquors

The paper deals with two rare earth elements (REE) concentrates recovered from uranium leach liquors after sorption separation of uranium. Activity of the REE concentrates was found to be 106 Bq kg−1; Ac-227 and its short-lived daughter products were the main radioactive impurities contributing more than 99% of total activity. Activity of both U-238 + Th-232 in the REE concentrates did not exceed 0.2% of total activity. Extraction by 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (P-507 extractant) in Shelsol D90 diluent was suggested for REE deactivation. It was shown that thorium may be eliminated by extraction in strong acidic media (pH − 0.5 to − 1), whereas radium extraction was suppressed over the whole studied pH range. Further REE separation to heavy and light groups at pH 1 resulted in selective concentration of actinium in light REE group. The suggested separation flowsheet was tested on the real REE concentrate. It was shown that obtaining non-radioactive fraction of heavy REE is possible.

Selective separation and recovery of vanadium from a multiple impurity acid leaching solution of stone coal by emulsion liquid membrane using di-(2-ethylhexyl)phosphoric acid

In order to overcome the problem of long extraction stages and huge consumption of organic phase in the solvent extraction process, selective separation and recovery of vanadium from a multiple impurity acid leaching solution of stone coal by emulsion liquid membrane (ELM) using di-(2-ethylhexyl)phosphoric acid (D2EHPA), as well as the effects of various parameters (surfactant, carrier, paraffin concentration and treat ratio (TR)) were studied. The extraction behaviors of V (V), V (IV), Fe (III), Fe (II), Mg (II), K (I), Na (I) in ELM process were reported and the effects of various impurities on vanadium extraction were also investigated. Finally, a separation flow sheet for a real solution was designed and an enriched vanadium solution was obtained with V 6.10g/L, Fe 0.30g/L, Al 3.20g/L, Mg 0.62g/L, K 0.24g/L, Na 0.20g/L, which revealed that vanadium was successfully separated and recovered from the stone coal acid solution bearing multiple impurity ions.

HF-Free Synthesis of α-Zirconium Phosphate and Its Use as Ion Exchanger for Separation of Nd(III) and Dy(III) from a Ternary Co–Nd–Dy System

The recovery of Nd and Dy from a ternary Co-Nd-Dy system using layered crystalline zirconium phosphate (alpha-ZrP) was investigated. alpha-ZrP was synthesized by the refluxing method, and subsequently characterized by sodium hydroxide titration, Fourier transform-infrared spectrometry, thermogravimetry, scanning electron microscopy, and X-ray diffraction. The selectivity and ion exchange kinetics of the alpha-ZrP material were determined with regard to the individual elements. The influence of solution pH on the uptake was studied in ternary 1 and 2 mM equimolar solutions. The results showed that in acidic solution (pH 1-3), very little Co was taken up, while Nd and Dy uptakes were at reasonable levels (0.5-0.6 meq/g). The uptake isotherms of Nd, Dy, and Co were measured separately at pH 2.5 and 4.5 in ternary equimolar solution series. At pH 4.5, the loading capacities were about 0.2 meq/g for Co, 1.1 meq/g for Nd, and 1.5 meq/g for Dy. Dy was thus clearly preferred over Nd by alpha-ZrP. The loading of an alpha-ZrP column showed a similar preferred pattern. Nitric acid eluent removed Co, Nd, and Dy, but there was no separation of the metals in the eluate. A mixture of nitric and phosphoric acids, however, produced a strong separation. Co was very weakly retained in the column, and the ratio Dy/Nd in the eluent was in the range of 2-7. Thus, the alpha-ZrP material showed encouraging ion exchange properties for the separation and recycling of Nd and Dy from a ternary Co-Nd-Dy system. Much more work is needed, however, to develop a practical separation flowsheet.

Technoeconomic Optimization of a Conceptual Flowsheet for Continuous Separation of an Analgaesic Active Pharmaceutical Ingredient (API)

Continuous Pharmaceutical Manufacturing (CPM) has recently emerged as a promising alternative to current batch production methods, which require significant expenditures in order to ensure product quality and process reliability. Advances in new continuous synthesis routes, demonstrations of full end-to-end continuous drug production and comparative technoeconomic analyses of potential cost advantages have all contributed to the advent of CPM and the strong interest of academic, corporate and regulatory beneficiaries. Continuous flow chemistry has been demonstrated for a variety of Active Pharmaceutical Ingredients (APIs), and there have been several landmark studies demonstrating practical CPM by illustrating the full design from raw materials to final product formulation. Fully continuous separations are critical to maximizing the CPM potential, but they are frequently not eludicated. This paper presents the formulation and solution of a nonlinear optimization problem for the CPM of ibuprofen. Adapting ...

Trace element concentration and reduction of typical Chinese bituminous coals via dry physical separation techniques

Dry physical separation techniques were used to clean typical Chinese bituminous coals by removing their ash and sulfur contents and major trace elements. Different dry coal separators, such as the conventional dense-medium gas–solid fluidized bed separator, vibrated dense-medium gas–solid fluidized bed separator, and triboelectric separator, were used to clean various-sized coal samples. Results suggested that the coal quality could be significantly improved through coal cleaning, which removed the mineral impurities of coal and therefore decreased its ash and sulfur contents. The majority of the trace elements were efficiently removed from run-of-mine coals and were found concentrated in the tailings after separation, thereby showing the highest removal efficiency for several harmful elements, including As, Co, Cr, Hg, and Mn in particular. Despite the removal percentage of the majority of trace elements, which obviously decreased with a decrease in the particle size of the coal sample, the overall removal efficiency satisfied the requirements of coal cleaning. The proposed dry physical separation flowsheet provides an alternative efficient approach to coal cleaning that can be utilized in the arid and water shortage countries.

Comparative analysis of sharp separation regimes in the distillation of ternary zeotropic mixtures

A comparative analysis of the direct and indirect splits and class-1 fractionation of ternary zeotropic mixtures has been carried out in terms of total vapor flow rate by means of a mathematical experiment. Composition regions in which a certain separation flowsheet minimizes the total vapor flow rate have been found.

Direct Reduction Experiment on Low-Grade Limonite at JiangXi

Considered the properties of limonite ore at Jiangxi, the raw ore pressing ball - direct reduction - magnetic separation flowsheet have been adopted. the pressing ball conditions, the influence factors and the grinding magnetic separation conditions experiments were carried out. The results shown that: When the dosage of coal was 20%, water was 10%, CMC was 0.5%, pressing ball under the pressure of 190 kN, the calcination temperature was 1100 °C, the roasting time is 50 min, roasted ore were magnetic separated after grinded to 85% through 200 mesh screen. the iron concentrate grade of 92.48% and recovery rate of 93.45% were achieved finally.

Beneficiation Test Research on Certain Iron Ming of Burma

The run of mine ore grade of Burma is 47.83%. According to the nature of the ore for the corresponding process, and the conditions of the test to explore, abstain to use a combined flowsheet for low magnetic separation - spiral chute - high gradient magnetic. The ultimate index for comprehensive grade of iron concentrate is 57.26%, at a total recovery of 83.07%, and obtain good experiment index.

Recovering Limonite by High Intensity Magnetic Separation Technology from Honghe Limonite Ore

High intensity magnetic separation tests have been carried out on the oolitic limonite ore with complex relations between limonite and gangue minerals of Honghe prefecture, and a optimal flowsheet for recover limonite from run-of-mine was adopted at last. High intensity magnetic separation flowsheet with one stage rougher, cleaner and scavenger, which have been studied respectively. Iron concentrate containing 55.18%Fe could be obtained at yield of 53.20% and recovery of Fe 68.45 % in closed circuit test.

New characterisation method of electrical and electronic equipment wastes (WEEE)

Innovative separation and beneficiation techniques of various materials encountered in electrical and electronic equipment wastes (WEEE) is a major improvement for its recycling. Mechanical separation-oriented characterisation of WEEE was conducted in an attempt to evaluate the amenability of mechanical separation processes. Properties such as liberation degree of fractions (plastics, metals ferrous and non-ferrous), which are essential for mechanical separation, are analysed by means of a grain counting approach. Two different samples from different recycling industries were characterised in this work. The first sample is a heterogeneous material containing different types of plastics, metals (ferrous and non-ferrous), printed circuit board (PCB), rubber and wood. The second sample contains a mixture of mainly plastics. It is found for the first sample that all aluminium particles are free (100%) in all investigated size fractions. Between 92% and 95% of plastics are present as free particles; however, 67% in average of ferromagnetic particles are liberated. It can be observed that only 42% of ferromagnetic particles are free in the size fraction larger than 20mm. Particle shapes were also quantified manually particle by particle. The results show that the particle shapes as a result of shredding, turn out to be heterogeneous, thereby complicating mechanical separation processes. In addition, the separability of various materials was ascertained by a sink–float analysis and eddy current separation. The second sample was separated by automatic sensor sorting in four different products: ABS, PC–ABS, PS and rest product. The fractions were characterised by using the methodology described in this paper. The results show that the grade and liberation degree of the plastic products ABS, PC–ABS and PS are close to 100%. Sink–float separation and infrared plastic identification equipment confirms the high plastic quality. On the basis of these findings, a global separation flow sheet is proposed to improve the plastic separation of WEEE.

Experimental Research of Oolitic Hematite in Hebei Province

Oolitic hematite is a kind of difficult procession mineral because of the finely dissemination particle and complex mineral composition. In this paper, ore quality, technology mineralogy and mineral processing technology were studied. Three different technology was tested. Results shows (1)with the fineness of 0.076mm 95%,iron concentrate grade reach 62.74% with a recovery of 46.80% by high intensity magnetic separation-reverse floatation flow sheet. (2)61.09% iron concentrate grade and 45% recovery could be got by four times intensity magnetic separation with four times grinding and four times gravity separation.(3) according to roasting 75-90min with temperature 800°C and ore-coal ratio of 11,iron concentrate grade is 62.74% and recovery is 87% by roasting-magnetic separation flow sheet. This experimental study provide a good basis for using oolitite hematite in Hebei province.

Separation Tests of Low-Grade Gold Ore with High Sulfur and Arsenic

With the rise of gold prices, a large amount of gold resources will be exploited, which leads to more and more refractory gold ore appeared. It has very important practical significance to accelerate the development of refractory gold resources. This paper has done the separation tests of low-grade gold ore with high sulfur and arsenic from Tianmashan, Tong Ling in China. The chemical elements component, mineral composition, and the dissemination of mineral and gold have been analyzed. The separation flowsheet tests have been explored, and the preliminary results and appropriate reagent regime have been obtained.

Separation Tests of Low-Grade Gold Ore with High Sulfur and Arsenic

With the rise of gold prices, a large amount of gold resources will be exploited, which leads to more and more refractory gold ore appeared. It has very important practical significance to accelerate the development of refractory gold resources. This paper has done the separation tests of low-grade gold ore with high sulfur and arsenic from Tianmashan, Tong Ling in China. The chemical elements component, mineral composition, and the dissemination of mineral and gold have been analyzed. The separation flowsheet tests have been explored, and the preliminary results and appropriate reagent regime have been obtained.

Recovery of Copper(II) and Nickel(II) from Plating Wastewater by Solvent Extraction

The solvent extraction technology was applied to recover Cu 2+ and Ni 2+ from plating wastewater. Lix984N was chosen as the extractant due to its good extraction performance. The influence parameters were examined. The results show that the separation of Cu 2+ and Ni 2+ from sulphate medium can be realized by adjusting pH value with the help of Lix984N. For extracting Cu 2+ and Ni 2+, the optimal pH values are 4 and 10.5, and the maximal extraction percentages are 92.9% and 93.0%, respectively. With recovered Cu 2+ and Ni 2+ stripped in 170 g·L −1 and 200 g·L −1 H 2SO 4 medium, the stripping percentages of Cu 2+ and Ni 2+ are 92.9% and 93.0%, respectively. This method is simple and can be used to recover Cu 2+ and Ni 2+ from plating wastewater. And a flow sheet for separation of Cu 2+ and Ni 2+ is presented.

Recovery of pure MnSO 4∙H 2O by reductive leaching of manganese from pyrolusite ore by sulfuric acid and hydrogen peroxide

Manganese leaching and recovery from pyrolusite ore, was investigated by using H 2SO 4 as a leachant and H 2O 2 as a reducing agent. The effects of agitation, H 2O 2 concentration, H 2SO 4 concentration, liquid/solid mass ratio, leaching time and reaction temperature on manganese recovery were studied. The optimal leaching conditions were determined as 4.0 M H 2SO 4 and 0.8 M H 2O 2 using liquid–solid mass ratio of 5.0 for 90 min at 40 °C and ore particle size of 44–37 μm. Under these conditions, the leaching efficiency was 92.0% for Mn. It was found that the use of H 2O 2 as a reducing agent for the reductive leaching of manganese increased the leaching rate. Analysis of the experimental results indicted that the leaching process is fitted by a chemical reaction model in temperature range 20–40 °C, and at higher temperature, 45–70 °C, the diffusion reaction model prevails. Activation energies for these models were calculated to be 49.5 kJ∙mol − 1 and 10.6 kJ∙mol − 1 , respectively. Based on the experimental results, a separation method and flow sheet were developed and tested to separate high purity MnSO 4.H 2O (> 99.4%). Comparison between the present results and that reported in the literature are given.

A Framework for the Systematic Design of Hybrid Separation Processes

The design of optimal separation flow sheets for multi-component mixtures is still not a solved problem. This is especially the case when non-ideal or azeotropic mixtures or hybrid separation processes are considered. We review recent developments in this field and present a systematic framework for the design of separation flow sheets. This framework proposes a three-step approach. In the first step different flow sheets are generated. In the second step these alternative flow sheet structures are evaluated with shortcut methods. In the third step a rigorous mixed-integer nonlinear programming (MINLP) optimization of the entire flow sheet is executed to determine the best alternative. Since a number of alternative flow sheets have already been eliminated, only a few optimization runs are necessary in this final step. The whole framework thus allows the systematic generation and evaluation of separation processes and is illustrated with the case study of the separation of ethanol and water.

Separation of iron(III), copper(II) and zinc(II) from a mixed sulphate/chloride solution using TBP, LIX 84I and Cyanex 923

Separation of iron(III), copper(II) and zinc(II) from a mixed sulphate/chloride leach liquor bearing 11.8 kg/m 3 iron, 24.8 kg/m 3 copper, 0.23 kg/m 3 zinc, 3.8 kg/m 3 cobalt, 35.2 kg/m 3 nickel, 176.3 kg/m 3 chloride and 48.9 kg/m 3 sulphate was carried out using solvent extraction. Iron, copper and zinc extraction studies were carried out using TBP, LIX 84I and Cyanex 923 in kerosene, respectively. The extraction studies were carried out for various metal ions at different pH and solvent concentrations and the optimized conditions were determined. The numbers of stages required for extraction and stripping of metal ions were determined from the McCabe–Thiele plot and confirmed from the counter-current simulation studies. Iron loaded TBP, copper loaded LIX 84I and zinc loaded Cyanex 923 were stripped with water, H 2SO 4 and water, respectively. Based on the data a flow sheet for separation of the three metal ions has been provided.

Synthesis of flowsheets for extractive distillation of azeotropic mixtures

An algorithm for synthesizing extractive distillation flowsheets for separation of complex ternary azeotropic mixtures with different vapor-liquid equilibrium patterns is proposed.