Precipitation Of Magnesium Hydroxide Research Articles

Electrochemical separation of sulfuric acid from magnesium sulfate solutions: Application for nickel laterite processing

Nickel has wide range of applications, and its production is expanding to meet the growing demand especially for energy storage applications. Hydrometallurgical nickel extraction from laterite ores requires a significant amount of sulfuric acid, primarily due to acid-consuming minerals such as magnesium silicates. The reaction of acid and magnesium silicates results in magnesium sulfate waste solution which is an environmental liability. Electrochemical separation can be used to produce acid from these waste solutions which can be reused on-site to increase nickel recovery from the resource. In addition, the generated magnesium hydroxide can be used for carbon capture or as a precipitant in the nickel process. In this work, a single membrane electrolyser was used to convert magnesium sulfate solutions into sulfuric acid and a magnesium hydroxide precipitate. The performance of the electrolyser was evaluated in terms of faradaic efficiency, acid production energy intensity, current density and sulfate recovery extent. This evaluation involved varying the electrolyser potential as well as the initial concentrations of catholyte and anolyte. The results indicated that when starting with a MgSO4 concentration of 1 M or lower and applying a 4 V electrolyser potential, 90 % faradaic efficiency can be maintained up to an anolyte concentration of 0.16 M H2SO4. Higher voltages, concentrations and conductivities across the anolyte and catholyte has a detrimental impact on the faradaic efficiency due to water splitting. High electrolyser potential enhances sulfate transport but also results in excessive Mg(OH)2 precipitation, which scales the cathode; an operational challenge that will need to be managed. Sulfate recovery ranged between 43 and 49 % after 4 h when testing initial anolyte concentrations of 0.1 and 0 M, with an average energy intensity of 2.94 and 4.44 kWh/kg-H2SO4, respectively.

Population balance modelling of magnesium hydroxide precipitation: Full validation on different reactor configurations

In this paper, a predictive mono-dimensional (1D) model for Mg(OH)2 precipitation is proposed and its predictive capability is tested. Two different reactor configurations are analyzed and compared, namely a T-mixer and a Y-mixer followed by two consecutive diverging channels and a final coil of constant diameter. Both setups were chosen for their high mixing efficiency. The suspension samples were characterized by Dynamic Light Scattering (DLS), thus obtaining particle size distributions (PSD). The experimental data collected using the T-mixer was used to identify the kinetics parameters set, while the data obtained through the Y-mixer setup was employed to assess the model predictive capability under different fluid dynamics conditions. Computational Fluid Dynamics (CFD) simulations were conducted to characterize the flow fields and the turbulence, which were integrated into the 1D model. Predictions were found to be in good agreement with the experimental data and further improved after introducing a novel correction factor for the aggregation kernel.

Computational Modeling of Magnesium Hydroxide Precipitation and Kinetics Parameters Identification.

Magnesium is a critical raw material and its recovery as Mg(OH)2 from saltwork brines can be realized via precipitation. The effective design, optimization, and scale-up of such a process require the development of a computational model accounting for the effect of fluid dynamics, homogeneous and heterogeneous nucleation, molecular growth, and aggregation. The unknown kinetics parameters are inferred and validated in this work by using experimental data produced with a T2mm-mixer and a T3mm-mixer, guaranteeing fast and efficient mixing. The flow field in the T-mixers is fully characterized by using the k-ε turbulence model implemented in the computational fluid dynamics (CFD) code OpenFOAM. The model is based on a simplified plug flow reactor model, instructed by detailed CFD simulations. It incorporates Bromley's activity coefficient correction and a micro-mixing model for the calculation of the supersaturation ratio. The population balance equation is solved by exploiting the quadrature method of moments, and mass balances are used for updating the reactive ions concentrations, accounting for the precipitated solid. To avoid unphysical results, global constrained optimization is used for kinetics parameters identification, exploiting experimentally measured particle size distribution (PSD). The inferred kinetics set is validated by comparing PSDs at different operative conditions both in the T2mm-mixer and the T3mm-mixer. The developed computational model, including the kinetics parameters estimated for the first time in this work, will be used for the design of a prototype for the industrial precipitation of Mg(OH)2 from saltwork brines in an industrial environment.

Enhancing the microstructure and surface texture of recycled concrete fine aggregate via magnesium-modified carbonation

Investigations on the carbonation of recycled concrete aggregates have been extensively carried out. In this work, recycled concrete fine aggregates (RCFs) were firstly treated with magnesium nitrate solutions of various concentrations and then carbonated. Extensive techniques were employed to characterize the changes of physical properties, pore structures, surface morphologies and phase assemblages of the RCFs after carbonation. Besides, the influences of carbonated RCFs on the hydration, compressive strength and phase assemblages of new cement systems were also evaluated. The results suggested that the magnesium-modified carbonation was more effective than pure carbonation in enhancing the microstructures of RCFs considering the reduction of total pore volume and water absorption. The refinement of microstructure was attributed to the formation of magnesium-calcite, hydromagnesite, etc. as a result of four sequential steps: adsorption of Mg2+ into RCF matrices, precipitation of magnesium hydroxide, enhanced dissolution of Ca2+ and the carbonation of magnesium hydroxide and calcium hydroxide mixes. In addition, the magnesium-modified carbonation was also found to significantly change the morphologies of carbonation products by generating spear-like magnesium-calcite, rosette-like hydromagnesite, plate-like hydrotalcite/mononitrate and spheroidal vaterite. The certain morphological changes of reaction products could promote the formation of an intersected 3D surface texture for RCFs. This particular surface texture could establish a well-connected interface with enhanced interlocking effects when the RCFs were used in new mortars, contributing to the bonding strength and compressive strength enhancement, and the best enhancement was achieved at low Mg2+ dosages (e.g., 0.05 M and 0.1 M).

Finding Optimized Process Conditions to Minimize Precipitations in an SO2 Absorption Process Using Thermodynamic Process Simulation

A process model to describe SO2 absorption from exhaust gas using an absorptive magnesium-based slurry was developed in Aspen Plus® V10. The model includes the thermodynamic description of the electrolyte system MgO-CaO-SO2-H2O-O2-CO2, including precipitation reactions in the system. The property method electrolyte-NRTL with an asymmetric reference state was chosen as the thermodynamic method. The model was evaluated using plant data for pH value, HSO3- and SO3-- content of the liquid phase from an industrial SO2 absorption venturi system of the pulp and paper industry. The model shows good accuracy in describing the pH value and the combined HSO3- and SO3-- content. Sensitivity analyses were performed to identify key parameters that influence unwanted precipitation reactions in the system and to support the optimization of the SO2 absorption process. Temperature and the Mg(OH)2/SO2 ratio in the system were identified as key parameters influencing the formation and precipitation of sulfites. The pH value was identified as a key parameter affecting the precipitation of magnesium hydroxide. The model predicts the precipitation of Mg(OH)2 at a pH value of higher than 8 and the precipitation of MgSO3 trihydrate at a temperature higher than 78 °C or a slurry/SO2 ratio higher than around 4. The performed analyses can support optimized process design decisions for SO2 absorption processes to avoid limiting precipitation issues.

Obtaining Magnesium Hydroxide From Dolomite Of The Dekhkanabad Deposit

The results of a study of the effect of pH on the chemical composition and degree of precipitation of magnesium hydroxide from clarified nitric acid extracts of dolomite decomposition are presented. It was found that the main amount of magnesium is precipitated by neutralizing the clarified extract from the dolomites of the Dekhkanabad field with gaseous ammonia to pH 11-12. The filtration rate of magnesium hydroxide on dry sediment is 181.80 kg/m 2 h. All solutions have acceptable rheological properties.

Autoflocculation of microalgae, via magnesium hydroxide precipitation, in a high rate algal pond treating municipal wastewater in the South Australian Riverland

High rate algal ponds (HRAP) are considered a promising system for coupling wastewater treatment with the growth of microalgae biomass. However, the absence of a cost-effective harvesting method limits this application. In this study, in situ autoflocculation, via magnesium hydroxide precipitation, was assessed in a HRAP containing 33 m3 of HRAP treated municipal wastewater which had a total suspended solids concentration of 115.00 mg L−1. Autoflocculation was induced using MgCl2.6H2O to increase the magnesium concentration of the wastewater to 82.63 ± 0.09 mg L−1, followed by the addition of 182 mg L−1 of slaked lime to increase the pH to 11. A high flocculation efficiency, determined by the reduction in turbidity, of 91.52 ± 0.57% was achieved with good removal of total suspended solids, 84.93 ± 1.00%. Excellent nutrient removal, 91.10 ± 0.14% of total phosphorus, and pathogen removal, a 3 log10 reduction in E. coli MPN 100 mL−1, was also observed. Hydrochemical modelling (PHREECQC-2) identified improvements in operational conditions to reduce cost. Autoflocculation, via magnesium hydroxide precipitation, was shown to be a promising method for harvesting microalgae and nutrients.

Investigation of surfactant effect during synthesis of magnesium oxide nanoparticles from bittern using ultrasonic destruction process

Magnesium oxide (MgO) nanoparticles have been widely used in a variety of applications because of their good surface reactivity. Magnesium oxide from bittern has a larger surface area compared to magnesium oxide from calcined magnesite and magnesium ions precipitation from bittern using sodium hydroxide has higher purity than using calcium hydroxide or ammonium hydroxide. In this research, sodium hydroxide was added to a bittern solution obtaining magnesium hydroxide precipitate, followed by the calcination process to produce magnesium oxide. Nano magnesium oxide was synthesized by the ultrasonic destruction process using ethanol and 2-propanol as media. In this study, sonication time and particle concentration effect on the ultrasonic destruction process were investigated. During the process, the sonication time was varied between 8, 16, 32, 64, and 128 minutes while the magnesium oxide concentration was varied between 1 %, 2 %, and 3 %. Increasing sonication time and particle concentration will decrease the particle size. The previous study shows that particles with very small sizes tend to have an agglomeration effect. The aim of this work is to optimize nano magnesium oxide production from bittern. Surfactant addition was also studied to prevent agglomeration between particles. Four types of surfactant namely anionic (sodium lauryl sulfate), cationic (cetyl tri-methyl-ammonium bromide), amphoteric (fatty acid amido alkyl betaine), and non-ionic (nonylphenol 10 ethoxylated) with a concentration of 1 % and a volume of 0.125 ml were added during the second ultrasonic destruction process. All types of surfactants have a positive effect to prevent agglomeration during the ultrasonic destruction process, with the amphoteric surfactant having the highest performance

ОСОБЛИВОСТІ ОСАДОУТВОРЕННЯ ГІДРОКСИДУ МАГНІЮ ПРИ НАПРАВЛЕНОМУ ГІДРОЛІЗІ В РОЗЧИНАХ ХЛОРИДУ МАГНІЮ

Magnesium compounds are common in nature as solid rocks and solutions in waters. The article has been analyzed variety of technologies and methods of use of various kinds of raw magnesium compounds, scientific and technological achievements, the state of magnesium production and tech-nology. Magnesium and its oxide and hydroxide are the most important for industrial use of magnesi-um compounds used in the production of steel, heat-resistant ceramics and structures, in the produc-tion of rubber products, plastics with special fire-resistant properties, as well as in the chemical, pharmaceutical industries, in medicine, in the production of optics, phosphors, single crystals, heed for magnesium compounds, important for new industries, caused the emergence of new studies and technologies. Important in the purification technologies of raw materials and technical solutions of magnesium chloride is the possibility of using magnesium hydroxide as effective sorbent and develop-ing conditions for separating the sediment in a wide range of concentrations. The processes of alka-line hydrolysis of magnesium chloride and the formation of the precipitate of its hydroxide in a wide range of concentrations were studied. The kinetics of the process and the features of separating such a sorbent from the purified solution of magnesium salt are studied. It is shown that the use of the princi-ple of homogeneous precipitation of magnesium hydroxide, performed in the proposed technology, is a fairly efficient and simple solution compared to those known. The conditions and mathematical regu-larities for obtaining the precipitate of magnesium hydroxide with a high filtration coefficient have been determined, which makes it possible to program the properties of the precipitate of magnesium hydroxide, to optimize the production of high-purity solutions of magnesium chloride, its hydroxide and oxide from it. The results of studies may use in medicine, in the production of new pharmaceuti-cals, standard samples, matrix collectors-sorbents and standards for metrological support in re-search.

Investigation of the calcareous deposits formation controlled by interfacial pH and its effect on the hydrogen entry into AISI 4135 steel in seawater

The influence of interfacial pH between AISI 4135 steel and seawater under different polarization potentials on the formation of calcareous deposits has been studied. An interfacial pH of 9.61 at −0.9 V vs. SCE using state of the art iridium oxide microelectrode was found to be the critical pH for the precipitation of magnesium hydroxide. Calcareous deposits with a double-layer structure comprising an inner-brucite layer and an outer-aragonite layer were found to form at potentials between −1.0 V and −1.2 V vs. SCE. Furthermore, the facilitation of hydrogen permeation into steel induced by the formation of calcareous deposits was verified using the Devanathan-Stachurski electrochemical test. The mechanism of calcareous deposits facilitates hydrogen permeation into steel is related to its inhibition on hydrogen recombination and escape processes.

Development of a co-precipitation process for the preparation of magnesium hydroxide containing lithium carbonate from Li-enriched brines

Ongoing research to develop a new generation of materials to achieve a more reliable and higher energy density lithium-ion batteries has attracted working groups attention worldwide in academia and industry. Products like lithium carbonate or lithium hydroxide are fundamental as the main feedstock for future materials. Recently, metal-atom substituted cathode materials with various metals has proved to improve the life-time, stability and performance of cathodes and consequently of the batteries. In this regard, this publication describes an approach to remove calcium impurities from industrial Lithium-rich brines with oxalic acid. Moreover, the present magnesium is reduced by the precipitation of magnesium hydroxide in a controlled manner in order to obtain a Lithium-enriched brine with a well-defined magnesium concentration in the absence of calcium. Finally, a process is presented to produce high purity lithium carbonate with controlled concentrations of magnesium between 1% to 3% as magnesium hydroxide. The magnesium hydroxide containing lithium carbonate is produced in a co-precipitation step, where initially the magnesium hydroxide is precipitated and subsequently the lithium carbonate is precipitated in a one-pot process.

Thermokinetic study of magnesium hydroxide obtained from seawater

In this paper, magnesium hydroxide has been obtained from seawater by a well-known industrial process which involves the chemical reaction between magnesium ions of seawater with dolomite lime to produce the magnesium hydroxide precipitate. Furthermore, the precipitate was modified by ultrasound of high intensity. The purpose was to obtain magnesium hydroxide with high purity and reduced particle size without agglomeration. The precipitated magnesium hydroxide is characterized by the particle size distribution determined by the laser scattering method in the range of 20 nm–2 mm, and by the SEM analysis. Likewise, in order to investigate the effect of particle size on the thermal stability, thermokinetic study of magnesium hydroxide samples was performed by non-isothermal thermogravimetry in an inert atmosphere at different heating rates. The gained thermogravimetric data were utilized for the kinetic analysis, which was performed by using the isoconversional Friedman method in combination with the multivariate nonlinear regression method. For each degradation stage of investigated samples, kinetic parameters (activation energy, pre-exponential factor and kinetic model) were calculated and compared.

Harvesting Porphyridium purpureum using polyacrylamide polymers and alkaline bases and their impact on biomass quality

This study aims to examine the flocculation efficiency of Porphyridium purpureum (i.e. a red marine microalga with high content of pigments and fatty acids) grown in seawater medium using polyacrylamide polymers and alkaline flocculation. Polymers Flopam™ and FO3801 achieved the highest flocculation efficiency of over 99% at the optimal dose of 21 mg per g of dry biomass through charge neutralisation and bridging mechanism. The addition of sodium hydroxide, potassium hydroxide, and sodium carbonate also achieved flocculation efficiency of 98 and 91%, respectively, but high doses were required (i.e. > 500 mg per g of dry biomass). Calcium hydroxide was not as effective and could only achieve 75% flocculation efficiency. Precipitation of magnesium hydroxide was identified as the major cause of hydroxide-induced flocculation. On the other hand, sodium carbonate addition induced flocculation via both magnesium and calcium carbonate co-precipitation. The large mass of precipitates caused a sweeping effect and enmeshed the microalgal cells to trigger sedimentation. Cell membrane integrity analysis of flocculated P. purpureum indicated that polyacrylamide polymers led to significant compromised cells (i.e. 96%), compared to the alkaline bases (70–96% compromised cells). These results appear to be the first to demonstrate the high efficiency of polyacrylamide polymer and alkaline flocculation of P. purpureum but at the expense of the biomass quality.

Dissolution mechanism of MgO thin film shielding layer in tunneling magnetoresistance hard disk drive read head

Magnesium oxide (MgO) thin films are used as magnetic shields and barriers for magnetic tunneling junctions in magnetic data storage devices. During the fabrication process, these films are exposed to water, causing a hydration reaction resulting in magnesium hydroxide precipitation. This hydration process can cause material loss and changes in the properties of the films, which may compromise the device performance. In this study, we investigate the dissolution of MgO thin films in deionized water. The magnitude and extent of the damage to the surface structures of the MgO films depend on the properties of the thin films and the time of dissolution. The surface roughness and morphology of the dissolved area are investigated by using atomic force microscopy and scanning electron microscope, respectively. It was found that the surface roughness increased with exposure time to water (from 1 to 10 h), corresponding to increasing film damage. Moreover, a model describing the reaction rate is created based on electrical conductivity measurements of dissolved MgO as a function of time.

Surface modification of biodegradable AZ91 magnesium alloy by electrospun polymer nanocomposite: Evaluation of in vitro degradation and cytocompatibility

Magnesium alloys have recently attracted significant attention for the fabrication of biodegradable orthopedic implants and cardiovascular stents. Nevertheless, the high degradation rate of magnesium alloys under physiological conditions is still challenging. We present a surface modification strategy to tailor the degradation rate and in vitro cell behavior of AZ91 alloy through electrospinning of continuous poly (ε-caprolactone) fibers containing bioactive glass nanoparticles (~30 nm). The average thickness of the nanocomposite film and the fibers are 30 μm ± 5 and 300 ± 31 nm, respectively. Electrochemical studies in simulated body fluid and standard immersion corrosion tests have determined that the degradation rate of the magnesium alloy is reduced by two orders of magnitude. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction analyses have shown the formation and precipitation of hydroxyapatite and magnesium hydroxides on the surface of fibrous film after 7 days of incubation. In addition to enhancing the in vitro bioactivity, osteosarcoma and fibroblast cell assays have revealed better cell adhesion and viability on the coated surface. The mechanisms of improved properties are ascribed to the effect of nanocomposite film on the hydrophilicity of the surface and mass transport through the fibrous structure as well as the presence of bioactive nanoparticles.

Analysis of the flocculation process of fine tailings particles in saltwater through a population balance model

A population balance model is used to describe the flocculation of tailings particles in aqueous salt solutions. The synthetic tailings, composed of quartz and kaolin particles, are flocculated in a jar at a constant shear rate where in-situ FBRM determines the size of the aggregates. The model follows the dynamics of aggregation and breakage processes and provides a good approximation to the temporal evolution of aggregate size. The fractal and permeable nature of the aggregates are considered, while the depletion of the collision efficiency allows describing the initial growth of aggregates and subsequent size reduction. The numerical solution requires five parameters, which are obtained by minimizing the difference between experimental size data and model predictions. A specific aim is to study the effect of magnesium hydroxide that is formed at pH ca. 10, and its interaction with flocculant, on the flocculation kinetics parameters. At pH ≥ 10 the aggregates grow less due to the presence of the magnesium hydroxide gel that surrounds quartz, kaolin and flocculant. The fractal dimension is quite stable at pH < 10 with a representative value of 2.7, typical of a clustered network, although in the presence of magnesium at pH ≥ 10 the fractal dimension of the aggregates is only 2.2, typical of Gaussian chains. Tailings aggregates in the presence of hydroxide are smaller and weakly three-dimensional and therefore contribute little to the settling velocity. The aggregation and breakage parameters are largely constant for a particulate system which composition remains unchanged over a pH range, and if the composition changes, for example by precipitation of magnesium hydroxide, then the aggregation parameters are different but close to constant.

Improved Lime Method to Prepare High-Purity Magnesium Hydroxide and Light Magnesia from Bischofite

Precipitation of magnesium hydroxide [Mg(OH)2] from bischofite (MgCl2·6H2O) using lime milk, i.e., the traditional lime milk method, features a low cost. However, insoluble impurities such as CaO in the lime limit the purity of the magnesium hydroxide product. For this reason, a new method has been developed, using saturated lime supernatant instead of lime milk. The insoluble impurities in lime cannot dissolve in saturated lime supernatant, thus improving the purity of the produced magnesium hydroxide. This improved lime method, which achieves high Mg(OH)2 purity of 99% with CaO content of 0.094%, offers better performance in comparison with the traditional lime milk method. Besides, the optimum processing parameters including pH, crystal seed amount, agitation speed, reaction temperature, MgCl2 concentration, reaction time, aging time, and polyacrylamide (PAM) addition are reported. High-purity light magnesia (MgO) is obtained from magnesium hydroxide by carbonation and calcination, with quality fulfilling the HG1-324-77 standard. This improved lime method represents a promising approach for production of high-purity magnesium hydroxide and light magnesia from bischofite.

Design and Application of High-Temperature Raw-Seawater-Based Fracturing Fluids

Summary Typically, water-based fracturing treatments consume a large volume of fresh water. Providing consistent freshwater sources is difficult and sometimes not feasible, especially in remote areas and offshore operations. Therefore, several seawater-based fracturing fluids have been developed in an effort to preserve freshwater resources. However, none of these fluids minimizes fracture-face skin and proppant-conductivity impairment, which can be critical for unconventional well treatments. Several experiments and design iterations were conducted to tailor raw-seawater-based fracturing fluids. These fluids were designed to have rheological properties that can transport proppant under dynamic and static conditions. The optimized seawater-based fracturing-fluid formulas were developed such that no scale forms when additives are mixed in or when the fracturing-fluid filtrate is mixed with different formation brines. The tests were conducted using a high-pressure/high-temperature (HP/HT) rheometer, coreflood, and by aging cells at 250 to 300°F. The developed seawater-based fracturing fluids were optimized with an apparent viscosity greater than 100 cp at a shear rate of 100 seconds–1 and a temperature of 300°F for more than 1 hour. The use of polymeric- and phosphonate-based scale inhibitors (SIs) prevented the formation of severe calcium sulfate (CaSO4) scale in mixtures of seawater and formation brines at 300°F. Controlling the pH of fracturing fluids prevented magnesium and calcium hydroxide precipitation that occurs at a pH value of greater than 9.5. Most importantly, SIs had a negative effect on the viscosity of seawater fracturing fluid during testing because of their negative interaction with metallic crosslinkers. The developed seawater-based fracturing fluids were applied for the first time in an unconventional and a conventional carbonate well and showed very promising results; details of field treatments are discussed in this paper.

Optimization of magnesium recovery from reject brine for reuse in desalination post-treatment

In this work, the recovery of magnesium from desalination reject brine through reaction with ammonia has been evaluated and statistically optimized using response surface methodology. The process is based on precipitation of magnesium hydroxide by the reaction of MgCO3 in the brine with ammonium hydroxide. A software, which is designed for studying chemical reaction and equilibrium, was employed to perform the thermodynamic analysis of the reaction of magnesium carbonate with ammonia, which was found to be exothermic and spontaneous in the temperature range of 0–22 °C. Central composite design (5-level, 3-factor) was used to optimize the process to obtain the maximum response of magnesium recovery as a function of reaction temperature, brine salinity, and ammonia to magnesium molar ratio. Maximum recovery of 99% was obtained at a temperature of 15 °C, brine salinity of 85 g/L, and a molar ratio of 4.4NH3: 1 Mg. The predicted response was in excellent agreement with the experimental results. The collected solid product at optimum conditions was characterized using X-ray Diffraction, Energy Dispersive Spectra analysis and thermogravimetric analysis. The analysis indicated the high purity of the recovered product in the form of Brucite (Mg(OH)2).

Effect of Pretreatment Process on Scale Formation in the Re-Boiler Section of Monoethylene Glycol Regeneration Plant

Monoethylene glycol (MEG) regeneration plants often use pretreatment vessels to precipitate divalent cations, such as Fe2+, Ca2+, and Mg2+, in order to avoid or reduce fouling in downstream reboilers and heat exchangers. This pretreatment process operates under alkaline conditions and moderate temperatures (~ 80 °C) to accelerate the formation of low-solubility divalent salts. The objective of the present research was to determine whether the pretreatment process could be minimized, without negatively impacts on the MEG regeneration process from to the formation of scale on the heater bundle in the presence of low concentrations of divalent cations in the rich MEG stream. Scale formation was analyzed under MEG regeneration process conditions using a dynamic scale loop (DSL) test and verification experiments were performed in a MEG regeneration and reclamation pilot plant, both with and without pretreatment conditions. The scaling tendencies of several rich MEG–brine mixtures were evaluated at different pH pretreatment levels and dissolved CO2 concentrations. An evaluation temperature of 180 °C was chosen to match the skin temperature of the reboiler heater bundle during the MEG regeneration process. The experiments of pH 7.24 showed high amounts of precipitation scale within the reboiler due to high remaining concentrations of mineral ions. In addition, small concentrations of calcium and magnesium ions led to the precipitation of calcite, dolomite, and magnesium hydroxide on the reboiler bundle and within associated filtered outputs even when a pretreatment vessel was present. These results were confirmed by the differential pressure build-up and Scanning Electron Microscopy analyses for each experimental condition. Another interesting finding is that pH increased within the reboiler due to CO2 gas boiling off at high operating temperatures, thus contributing to increased alkalinity levels, which in turn promoted scale formation. These results indicate that pretreatment should not be reduced, even with divalent ion concentrations as low as ~ 5 ppm TDS, due to the harsh conditions within the reboiler heater bundle.