Reactive Crystallization Process Research Articles

Crystallization of battery-grade lithium carbonate with high recovery rate via solid-liquid reaction

Lithium carbonate (Li2CO3) stands as a pivotal raw material within the lithium-ion battery industry. Hereby, we propose a solid-liquid reaction crystallization method, employing powdered sodium carbonate instead of its solution, which minimizes the water introduction and markedly elevates one-step lithium recovery rate. Through kinetic calculations, the Li2CO3 solid-liquid reaction crystallization process conforms by the Avrami equation rather than shrinking core model, which means the dissolution rate of Na2CO3 is the most important factor affecting the reaction process. The effects of reaction conditions such as temperature and stirring speed on the Li2CO3 precipitation behavior were evaluated. The results indicated that temperature is a most essential parameter than other reaction conditions or stirring speed. The exceptional 93% recovery of Li2CO3 at 90 °C with a remarkable purity of 99.5% was achieved by using 1.2 M ratio of Na2CO3/Li2SO4. This method provides a new idea for the efficient preparation of battery-grade Li2CO3.

Sequential Selection for Minimizing the Variance with Application to Crystallization Experiments

For many crystal-based products (e.g., pharmaceuticals, energy storage), the size uniformity is not only a key quality attribute, but sometimes also an indicator of other attributes such as solid purity. This paper proposes a sequential selection approach to find a proper experimental setting that leads to high uniformity, or equivalently, small variance for crystal sizes, from the advanced slug flow reaction crystallization process of a model crystal, called manganese oxalate hydrate. The proposed sequential selection approach contains a Bayesian adaptive method to incorporate new uniformity measurements in each step and two design acquisition functions to improve the selection of the most promising experimental setting in terms of minimizing the variance. We study the performance of the proposed approach through multiple synthetic numerical studies, as well as a case study based on data from slug flow crystallization experiments. Throughout these studies, the proposed approach shows competitive performance in identifying the best experimental setting.

Modeling of an unseeded reactive crystallization process using multiobjective optimization

Modeling of reactive crystallization processes is considered to be a complex task where the reaction and crystallization processes occuring together presents additional challenges. A simplified approach is shown in this work to model such reactive crystallization processes using limited number of experiments covering the design space. In the current application, a case study is demonstrated using unseeded semi-batch reactive crystallization of salicylic acid. Multiobjective optimization (MOO) approach is used to determine the kinetic model parameters considering surrogate objectives related to solution concentration and mean size of crystals using the experimental data collected. The proposed first principles model is in good agreement with the experimental data and thus can be further applied for model predictions to determine optimal control strategies.

Combined application of microbes immobilized carbon reactor and the reactive struvite system for the management of tannery deliming wastewater.

This present study investigated the removal of COD and ammoniacal nitrogen (NH4+-N) from tannery deliming wastewater (TDLWW) through microbesimmobilized carbon consisted a bioreactor (MICCR) and reactive struvite crystallization process. Initially, 90% of the organic content of TDLWW was removed using a MICCR reactor at 24 h retention time. Nanoporous carbon (NPC) was used as the carrier matrix for the MICCR reactor. SEM and AFM images of NPC used in the MICCR reactor identify different microorganisms on its surface. The microbial profile of NPC used in the MICCR was analyzed, and the relative abundance is phyla Firmicutes, 25.64%; Proteobacteria, 43.68%; Bacteroidetes, 6.58%; Cyanobacteria, 2.22%; Actinobacteria, 2.34% reason for organic removal. The removal of organics follows the pseudo-second-order rate kinetics with the rate constant of 1.75×10-3L COD-1 h-1. For the reactive struvite crystallization, MgO and Na2HPO4.2H2O were taken as the precipitating agents. The optimum molar ratio for the maximum conversion of NH4+-N into struvite was obtained as 1:1.4:1.4 (NH4+-N:MgO:Na2HPO4.2H2O). The volume of struvite precipitate was 48.5mL/L of TDLWW, and the dry weight was 8.89 g/L. More than 93% of NH4+-N was converted as the struvite fertilizer. The conversion of NH4+-N into struvite follows the pseudo-first-order rate kinetics with the rate constant of 1.67×10-2 min-1. Despite the conversion of NH4+-N into struvite, COD removal was observed, which confirms the conversion of organic nitrogen into struvite. The struvite was evaluated using SEM, XRD, TGA, DSC, and FT-IR spectroscopic analysis. Hence, the integrated MICCR and the reactive struvite crystallization process can be applied to manage tannery deliming wastewater.

Membrane assisted reactive crystallization with multiple interfacial flow regimes for effective mass transfer control

Herein, membrane-assisted reactive crystallization (MARC) with effective interfacial flow regimes was proposed to achieve the effective mass transfer control during reactive crystallization. Three tube-shell side solution systems (EtOH-H2O, Butanol-H2O and H2O-H2O) were chosen to form different flow regimes on the membrane surface, including the microscale liquid layer and the uniform droplets. The fundamental mechanisms of ‘rising and falling tide’ phenomenon, and flexible layer thickness control were uncovered. A force analysis model was established to illustrate the transition behavior of the droplet and liquid layer on the membrane surface. Molecular simulations additionally demonstrated that MARC implemented various ion diffusion conditions in different solution systems. Compared to the conventional reactive crystallization, MARC with multiple flow regimes can achieve effective control of CaCO3 crystal size ranging from 700 nm to 3 μm and obtain uniform size distribution (coefficient of variation less than 15.1 %), which shed light on the advanced material manufacture with reactive crystallization process.

Preparation of battery-grade lithium carbonate by microbubble enhanced CO2 gas–liquid reactive crystallization

A microbubble enhanced CO2 gas–liquid reactive crystallization process for the one-step preparation of battery-grade Li2CO3 has been proposed. The LiFePO4 cathode synthesized from battery-grade Li2CO3 exhibits a remarkable specific capacity.

Periodic wet milling as a solution to size-based separation of crystal products from biocatalyst for continuous reactive crystallization

Combining the synthesis and crystallization of a compound into a single step may be beneficial for certain processes. Motivations range from process intensification to improving reaction network yield by shifting an equilibrium limited reaction or protecting an intermediate, as is the case in the biocatalytic synthesis of beta-lactam antibiotics. Adapting such a reactive crystallization process to continuous manufacturing faces a challenge: the continuous separation of crystals from biocatalyst carriers. In this study, a size-based method for this separation problem is proposed. Separation is performed using a filter placed on the reactive crystallization vessel outlet. The primary factors for filter design are carrier and crystal size dictated by the separation condition Lcrystal<Lfilter<Lcarrier. Enzymatic assays confirmed an increasing loss of activity and selectivity for the biocatalyst, Penicillin G Acylase, when large carrier sizes are used for immobilization, limiting the maximum Lcarrier that can be used in the process. Intermittent wet milling, however, is shown to be effective in reducing the crystal size and allowing the use of sufficiently small carriers while still satisfying the criterion for solid–solid separation. Slurry transfer tests were performed to check the possibility of isokinetic withdrawal when the separator filter was used. Filter size of 300μm, a carrier size of 300–425μm, and intermittent wet milling of 2–3 reactor volumes per residence time at 5000RPM were found to provide an almost complete separation, acceptable biocatalyst kinetics, and an isokinetic crystal product withdrawal.

An Ultrasound Tomography Method for Monitoring CO2 Capture Process Involving Stirring and CaCO3 Precipitation.

In this work, an ultrasound computed tomography (USCT) system was employed to investigate the fast-kinetic reactive crystallization process of calcium carbonate. USCT measurements and reconstruction provided key insights into the bulk particle distribution inside the stirred tank reactor and could be used to estimate the settling rate and settling time of the particles. To establish the utility of the USCT system for dynamical crystallization processes, first, the experimental imaging tasks were carried out with the stirred solid beads, as well as the feeding and stirring of the CaCO3 crystals. The feeding region, the mixing process, and the particles settling time could be detected from USCT data. Reactive crystallization experiments for CO2 capture were then conducted. Moreover, there was further potential for quantitative characterization of the suspension density in this process. USCT-based reconstructions were investigated for several experimental scenarios and operating conditions. This study demonstrates a real-time monitoring and fault detection application of USCT for reactive crystallization processes. As a robust noninvasive and nonintrusive tool, real-time signal analysis and reconstruction can be beneficial in the development of monitoring and control systems with real-world applications for crystallization processes. A diverse range of experimental studies shown here demonstrate the versatility of the USCT system in process application, hoping to unlock the commercial and industrial utility of the USCT devices.

Real-Time Fault Detection and Diagnosis of CaCO3 Reactive Crystallization Process by Electrical Resistance Tomography Measurements.

In the present research work, an electrical resistance tomography (ERT) system is utilized as a means for real-time fault detection and diagnosis (FDD) during a reactive crystallization process. The calcium carbonate crystallization is part of the carbon capture and utilization scheme where process monitoring and malfunction diagnostics strategies are presented. The graphical logic representation of the fault tree analysis methodology is used to develop the system failure states. The measurement consistency due to the use of a single electrode from a set of ERT electrodes for malfunction identification is experimentally and quantitatively investigated based on the sensor sensitivity and standard deviation criteria. Electrical current measurements are employed to develop a LabVIEW-based process automation program by using the process-specific knowledge and historical process data. Averaged electrical current is correlated to the mechanical failure of the stirrer through standard deviation evaluation, and slopes of the measured data are used to monitor the pump and concentrations status. The performance of the implemented methodology for detecting the induced faults and abnormalities is tested at different operating conditions, and a basic signal-based alarming technique is developed.

Preparation of hydrotalcite crystals using impinging jet mixers

The active pharmaceutical ingredient hydrotalcite (aluminium magnesium carbonate hydroxide hydrate) is an antacid marketed either as suspensions or tablets. It is necessary to have stringent control on multiple crystal properties not only due to the demand on high quality of the medicine but also as a result of the need to improving the efficiency of down-stream processing e.g. of filtration of crystals. This work investigated impinging jet mixers integrated with a stirred tank for the preparation of hydrotalcite crystals, using aluminum sulfate, sodium carbonate and porous magnesium hydroxide as the raw materials. The new process design has shown superior performance to the commonly used stirred tanks. The hydrotalcite crystals were of narrow particle size distribution, large size and high bulk density, high purity, and uniform morphology. An attempt was also made at trying to develop mechanistic understanding of the reactive crystallization processes taking place inside the integrated impinging jet mixers - stirred tank equipment. Firstly the impinging jet mixers enabled generation of ultrafine aluminum hydroxide particles during the reactive precipitation between sodium carbonate and aluminum sulfate aqueous solutions. Then, the ultrafine aluminum hydroxide accumulated in the shallow layer of the porous magnesium hydroxide particles and gradually filled the porous particles under the stirring effect of the tank reactor. Meanwhile, the magnesium hydroxide gradually reacted with aluminum hydroxide to generate hydrotalcite from the surface towards the inside of the particles, and finally produced the high quality hydrotalcite crystals.

High selective synthesis of CaCO3 superstructures via ultra-homoporous interfacial crystallizer

Precise regulation of biomimetic mineralization for highly ordered superstructures is one of the perpetual concerns in biomaterial synthesis and crystal engineering. Herein, we propose a ultra-homoporous interfacial crystallizer (UHIC) as a novel interfacial microdevice, which has realized high selective synthesis of CaCO3 superstructures during Gas–Liquid reactive crystallization process. This UHIC with ultra-uniform mass transfer porous channel and interfacial superhydrophilicity render the droplet ultra-homo nucleation site and coordinatively regulate the interfacial nucleation energy. The highly precise microchannel in UHIC can control the CO2 gas flow rate and sufficient interfacial Gas–Liquid diffusion of the CaCO3 pre-nucleation cluster (PNC). By coordinating the PNC diffusion, self-organization and nucleus growth, the proportion of synthesized CaCO3 crystals with spherical and polyhedral structures both increased to higher than 96.77 %, and the crystal size distribution was very uniform (minimum C.V. =11.7%). Fundamental theory of CaCO3 synthesis with UHIC as a desire interfacial reactive were then outlined, which can shed light on the high-selective synthesis of the microscale biomaterials.

Investigation of ultrasonication and/or mechanical stirring on the reactive crystallization of calcium carbonate at lower temperature and higher supersaturation condition

Calcium carbonate (CaCO3, CC) distributes diversely among the abiotic and biogenic minerals/biominerals. It has six phases (three anhydrous crystalline, two hydrates and one amorphous). Phase selectivity of the synthetic CC is of considerable interest and determines its physicochemical properties and destinated applications.In the present study the reactive crystallization process of CC has been subjected to the treatment of different disturbances, i.e., mechanical stirring (ms), ultrasonication (us), and composed ms + us at lower temperature (0 ± 1℃) and higher supersaturation condition (initial concentration of Ca2+ is 0.1 M), in comparison with the quiescent condition. In order to gain insight on the role of these disturbances in controlling the crystallization process, nature, crystal habits of precipitated CC and their consecutive phase transformation, samples were collected at different time intervals (30 s, 1 min, 5 min, 10 min, 20 min, 45 min and 60 min) for investigation. Results reveals that these disturbing ways play a significant role on the CC crystallization process and can stabilize the amorphous calcium carbonate (ACC) phase for prolonged periods of time (1–60 min) in aqueous solution, which will be a powerful way for large-scale fabrication of pure ACC nanoparticles (about 100 nm) without addition of any chemicals. Longer disturbing time tends to transform the pure and spherical ACC nanoparticles competitively into spherical vaterite particles and rhombohedral calcite particles through the self-assembly of nanoparticles aggregation or Ostwald ripening mechanism, respectively. The investigation also suggested that the reactive crystallization of CC with the three disturbances undergoes a non-classical crystallization pathway to crystallize CC particles, in comparison with the quiescent reference condition. To the best of our knowledge, the report on reactive crystallization of CC crystallites as a function of different disturbances is first of its kind in the literature.

A perspective review on mixing effect for modeling and simulation of reactive and antisolvent crystallization processes

Reactive and antisolvent crystallization processes are sensitive to mixing effects on various scales.

The efficient development of a sildenafil orally disintegrating tablet using a material sparing and expedited approach.

The purpose of this work is to develop an orally disintegrating tablet (ODT) of sildenafil (SIL) using a materials sparing and expedited development approach, enabled by the materials science tetrahedron principle and predictive technologies. To overcome the problem of bitter taste of SIL, an artificial sweetener, acesulfame (Acs), was used to form a sweet SIL salt (SIL-Acs) using an effective reaction crystallization process to prepare phase pure bulk SIL-Acs with a high yield. The SIL-Acs salt shows excellent thermal stability (Tm=200.2°C), low hygroscopicity, and acceptable dissolution rate. Formulation and process parameters were optimized based on powder flowability, tabletability, tablet disintegration time, and expedited friability. A particle engineering approach, i.e., nanocoating, was employed to attain adequate flowability of the SIL-Acs ODT formulation required for the direct compression process. The wide range of compression forces for making tablets exhibiting both fast disintegration time (≤30s) and low friability (≤0.8%) suggested excellent flexibility in manufacturing SIL-Acs ODT. The development of a sildenafil ODT formulation, including solid form selection and characterization, crystallization method development, formulation development, and DC process optimization, only required 5g of SIL citrate and 2weeks of time.

Dynamic modeling and semibatch reactive crystallization of calcium carbonate through CO2 capture in highly alkaline water

A laboratory scale integration of carbon capture and utilization (CCU) technique operating based on highly alkaline aqueous hydroxide sorbents with a semibatch reactive crystallization process of calcium carbonate is presented. The study was conducted with a focus on investigating the kinetics of the crystallization process for CCU applications, where the production of micron-sized calcium carbonate particles occurs by direct addition of CO2-loaded solution to a crystallizer containing calcium chloride.Within this system, the need for high temperature heat consumption above 800 °C (109.4 kJ/mol CO2) for CO2 decomposition from Na2CO3 is avoided by production of value-added chemical from carbonate reach solution. The current set-up enables potential pre-treatment of carbon emission sources due to separate absorption and liquid-liquid crystallization processes. This leads to production of high-purity solid particles in comparison to conventional industrial practices.Experiments were carried out at several operating conditions at ambient temperature and pressure and effect of the absorbent solution concentration on CO2 capture efficiency and subsequently the precipitation yield was analyzed. Based on coupling the standard method of moments approach of the population balance formulation with power-law kinetic expressions, a correlation was extracted between the growth rate constant and feed flow rate for the adopted process. Moreover, characterization of the precipitated sample indicates the vaterite polymorphs of calcium carbonate as the dominant crystals in the pH range of 7.9–10.4. These types of demonstrations could contribute to circular economy processes using waste materials and can be considered as a potential approach toward an efficient carbon capture and valorization technique.

Production of Zn(l-Met)2 Chelate with Improved Flowability by Reactive Crystallization

The production of zinc l-methionine chelate (Zn(l-Met)2) by a fed-batch reactive crystallization process was reported with enhanced flowability. Zn(l-Met)2 chelate was obtained through the injectio...

High-throughput on demand access of single enantiomers by a continuous flow crystallization process

A novel continuous flow reactive crystallization process for the in situ on-demand access of single enantiomer crystals is reported and exemplified for a chiral pharmaceutical intermediate that crystallizes as a racemic conglomerate.

Effect of reaction crystallization process parameters on struvite recovery from animal wastewater in presence of boron, cobalt, manganese and molybdenum

Effect of reaction crystallization process parameters on struvite recovery from animal wastewater in presence of boron, cobalt, manganese and molybdenum

Continuous Synthesis of Barium Sulfate Nanoparticles in a New High-Speed Spinning Disk Reactor

A new high-speed spinning disk reactor (HSSDR) was proposed and tested successfully. In this regard, barium sulfate (BaSO4) nanoparticles were synthesized using reactive crystallization processes. ...

Mechanism and Modelling of Reactive Crystallization Process of Lithium Carbonate

The reactive crystallization of lithium carbonate (Li2CO3) from lithium sulfate (Li2SO4) and sodium carbonate (Na2CO3) solutions is a key process in harvesting solid lithium, whether from ores, brines, or clays. However, the process kinetics and mechanism remain poorly understood and the modelling of the reactive crystallization of Li2CO3 is not available. Hence, this work aims to determine the kinetics and mechanisms of the nucleation and growth of Li2CO3 reactive crystallization by induction time measurements and to model and optimize the crystallization process using response surface methodology. Induction time measurements were carried out as functions of initial supersaturation and temperature using a laser method. It was found that the primary nucleation mechanism of Li2CO3 varies with solution supersaturations, in which, expectedly, the heterogenous nucleation mechanism dominates at low supersaturations while the homogeneous nucleation mode governs at high supersaturations. The transition point between heterogenous and homogenous nucleation was found to vary with temperatures. Growth modes of Li2CO3 crystals were investigated by relating induction time data with various growth mechanisms, revealing a two-dimensional nucleation-mediated growth mechanism. The modelling and optimization of a complex reactive crystallization were performed by response surface methodology (RSM), and the effects of various crystallization parameters on product and process performances were examined. Solution concentration was found to be the critical factor determining the yield of crystallization, while stirring speed was found to play a dominant role in the particle size of Li2CO3 crystals. Our findings may provide a better understanding of the reactive crystallization process of Li2CO3 and are critical in relation to the crystallization design and control of Li2CO3 production from lithium sulfate sources.