Solid- liquid phase separation and resource recycling study for waste rolling oily sludge

On the basis of the characteristics of a highly emulsified solid-liquid phase （fine particles, sticky consistency,black color, and low reuse ratio）, waste rolling oily sludge has been a focal problem in the steel industry. In this article, a solid-liquid phase separation and resource recycling process was described, with pilot test results showing that flocculation-sedimentation is an effective pretreatment, and that the filtration-coagulationvacuum distillation process is simple and feasible with a 53.5% recovery rate for regenerated oil that is qualified for return to the roiling production line. Then,solid phase oil-sludge was extracted by solvents with a 77% metal resource recovery rate and a wide utilization range. Finally, according to the experimental results, a set of feasibility plans for a 50 t/a waste rolling oily sludge solid-liquid separation and resource recycle project was designed, with the expectation of 50% regenerated oil yield, 70% solid metal resource recovery, and a 2. 5-year investment payback period.

Solvent impregnated resin prepared using ionic liquid Cyphos IL 104 for Cr(VI) removal

Ionic liquid (IL) trihexyl (tetradecyl) phosphonium bis 2,4,4-trimethylpentylphosphinate (Cyphos IL 104) was impregnated on XAD-7 resin. The solvent impreganated resin (SIR) was prepared and applied in Cr(VI) removal. The morphology and the thermal stability of the resins were explored. The effects of equilibrium time and initial pH value on Cr(VI) adsorption were investigated. Adsorption isotherm, separation and desorption of the SIR, and selectivity of SIR were also explored. The results show that Cyphos IL 104 exists in the inner XAD-7 resin, and the optimum pH value range of the SIR for Cr(VI) extraction is 0 to 2. When NaOH used as desorption solution, the Cr(VI) can be effectively desorbed from the SIR.

Surface nanobubble characterization and its enhancement mechanisms for fine-particle flotation:A review

Froth flotation is often used for fine-particle separation,but its process efficiency rapidly decreases with decreasing particle size.The efficient separation of ultrafine particles(UFPs)has been a major challenge in the mineral processing field for many years.In recent years,the use of surface nanobubbles in the flotation process has been recognized as an effective approach for enhancing the recovery of UFPs.Compared with traditional macrobubbles,nanobubbles possess unique surface and bulk characteristics,and their effects on the UFP flotation behavior have been a topic of intensive research.This review article is focused on the studies on various unique characteristics of nanobubbles and their mechanisms of enhancing the UFP flotation.The purpose of this article is to summarize the major achievements on the two topics and pinpoint future research needs for a better understanding of the fundamentals of surface nanobubble flotation and developing more feasible and efficient processes for fine and UFPs.

Isolated mixing regions and mixing enhancement in a high-viscosity laminar stirred tank

Laminar mixing in the stirred tank is widely encountered in chemical and biological industries.Isolated mixing regions(IMRs)usually exist when the fluid medium has high viscosity,which are not conducive to mixing.In this work,the researches on IMRs,enhancement of laminar mixing and the phenomenon of particle clustering within IMRs are reviewed.For most studies,the aim is to destroy IMRs and improve the chaotic mixing.To this end,the mechanism of chaotic mixing and the structure of IMRs were well investigated.The methods developed to destroy IMRs include off-centered agitation,dynamic mixing protocol,special designs of impellers,baffles,etc.In addition,the methods to characterize the shape and size of IMRs as well as mixing effect by experiments and simulations are summarized.However,IMRs are not always nuisance,and it may be necessary in some situations.Finally,the present engineering applications are summarized,and the prospect of the future application is predicted.For example,particle clustering will form in the co-existing system of chaotic mixing and IMRs,which can be used for solid–liquid separation and recovery of particles from high viscosity fluid.

Coordination chemistry of surface-associated ligands for solid-liquid adsorption of rare-earth elements

General guidelines for the design of ligands for the enrichment of rare-earth elements by solid-liquid adsorption are described using coordination chemistry.Relevant properties of ligands include selectivity of metal ions based on adjustment of donor atom polarizability,denticity,and the pKarange of the binding sites.The selectivity of solid-phase materials for the enrichment of rare-earth ions by the ligand design guidelines is outlined,with special consideration of additional variable factors including steric hindrance,saturated binding sites,variability in speciation caused by the identity of counterions and ionic strength,and size-exclusivity in ligands stemming from differences in bite angle,preo rganization of ligands,or intraligand interactions.This review analyzes some principles of selectivity of rare-earth elements with ligands organized by donor type from examples collected from reports published between 2009 and 2021.

Effect of preozonation on improvement of settleability of solid in highly concentrated organic wastewater of Japanese wheat and sweet potato spirit-distillery

Solid-liquid separation of the wastewater is very difficult because of high viscosity and high SS concentration. In this study, the effectiveness of preozonation on improving the settleability of the solids in wheat and sweet potato wastewaters was investigated using a bench-scale system and pilot treatment system respectively. Results showed that solid-liquid separation in the wheat wastewater was greatly improved by the decanter in the system(SS reduction from 24100 mg/L to 100 mg/L). However, preozonation practice did not show a significant effect on solid-liquid separation of the sweet potato wastewater. Effect of preozonation on solid-liquid separation between wheat and sweet potato wastewater showed different.

Bio-inspired Filter Design Based on Vortex Control Mechanism of Parallel Groove Structure

Solid–liquid separation is widely used in daily life and practical engineering.Traditional industrial filters are prone to clogging,but this rarely occurs in filter-feeding organisms.Inspired by the filter feeding mechanism of balaenid whales and considering the local grooves in the fringes layer,a new bionic filter is produced by 3D printing technology through the bionic design of the parallel channels inside the mouth of balaenid whales.At the same time,a test platform composed of the bionic filter,peristaltic pump,fluid pulse rectifier and water tank is built to carry out the fluid flow pattern dyeing and particle filtration experiments.It is found that fluid separation occurs near the groove structure and local vortices are generated.The vortex control filtration mechanism makes the particles in the front grooves tend to accumulate on the left side,which has a certain anti-clogging effect.Moreover,the increase of flow velocity leads to the enhancement of vortices,which makes the accumulation effect on the left more obvious.This study initially practices the bionic application from biological model to engineering design,and the vortex control anti-clogging filtration mechanism proposed in the study has a wide range of application prospects and values.

Modeling of specific structure crystallization coupling with dissolution

In this paper,the research framework for specific structure crystallization modeling has been proposed in which four steps are required in order to investigate the rigorous crystallization modeling by thermodynamics.The first is the activity coefficient model of the solution,the second is Solid-Liquid equilibrium,the third and fourth are the dissolution and crystallization kinetics modeling,respectively.Our investigations show that the mechanisms of complex structure formation and microphase transition can be analyzed by combining the dissolution and crystallization kinetics modeling.Moreover,the formation mechanism of the porous KCl has been analyzed,which may provide a reference for the porous structure formation in the advanced material synthesis.