Synthetic Tailings Research Articles

Floating reactive barriers to mitigate secondary organic aerosol formation from oil sands tailings ponds

Oil sands operations to recover bitumen in Alberta, Canada generate large volumes of contaminated water which are stored in tailings ponds. These ponds emit large quantities of intermediate / semi- volatile organic compounds (IVOC/SVOCs) which upon emission can react or partition to form secondary organic aerosols (SOAs), a significant issue concerning human and environmental health. These ponds are one of the largest sources of SOAs in North America, and the responsible VOCs (polycyclic aromatic hydrocarbons (PAHs), alkanes, single ring aromatics) are difficult to treat. Passive technologies that can reduce aqueous emissions and degrade volatiles in-situ are desired. A promising technology is buoyant photocatalysts (BPCs), which float on the surface of water bodies and absorb sunlight to oxidize contaminants. In this work, a glass microsphere TiO2-coated BPC is studied, which forms a semi-porous floating reactive barrier on the surface of water, intercepting VOC emissions and photocatalytically oxidizing them in water before they can be released to air. Based on a group of F2 – F3 hydrocarbons, 16 PAHs (C10 – C22) and 8 alkanes (C11-C18), this BPC technology reduced 89% of these SOA precursor emissions while degrading 84% of the compounds in the system under 2 days of simulated sunlight. In a synthetic tailings pond environment, BPCs were demonstrated to block and treat VOCs of particular concern well (phenanthrene, pyrene, chrysene), while further preventing emissions from free phase hydrocarbons. In context of tailings pond SOA precursor emissions, application of this floating reactive barrier technology to all ponds could reduce the environmental impact of oil sands operations by preventing release of between 2400 to 11000 tonnes of SOAs per year. The proven ability to intercept and treat VOCs in water extends the potential of this technology past the oil sands industry, providing one of the first options for passive fugitive emission management for various industrial water bodies. SynopsisBuoyant Photocatalysts permanently prevent aqueous gas emissions and likely subsequent secondary organic aerosol formation by preventing release while oxidizing aqueous volatiles.

Effect of solution pH and polyethylene oxide concentration on surface/interface properties, flocculation and rheology of concentrated monodisperse ultrafine synthetic tailings slurry

The effects of polyethylene oxide (PEO) dosage and solution pH on the flocculation, rheological and surface/interfacial properties of the slurry were investigated by sedimentation, rheology, adsorption and surface force experiments. The results demonstrate that the initial settling rate (ISR) of the tailings is at its lowest in strongly acidic solutions. The ISR reaches its peak in strongly alkaline solutions. The PEO dosage exhibits a modest impact on the yield stress of the concentrate in strong acid solutions, while it wields a notable influence on the yield stress in neutral and strongly alkaline solutions. Quartz crystal microbalance with dissipation (QCM-D) measurements reveal that strong alkaline solutions enhance the adsorption of PEO chains on silica surfaces. Strongly acidic solutions partially inhibit the adsorption of PEO chains. Surface force measurement results indicate that PEO chains can bridge the tailings particles in concentrated suspensions through hydrogen bonding, and consequently elevating the suspension's yield stress.

Extratidal Members of Segue 3 are Rare and Difficult to Confirm

We simulate extratidal members of Segue 3, a sparse, faint, and small, ∼2.6 Gyr halo cluster, and investigate their observational detectability. Using the Gala package to simulate Segue 3's potential tidal tails, we find that the tails are narrow, linear, and around 4°–6° in length: the tails’ position angles and width are most sensitive to the uncertainties in the cluster's distance and mean proper motion. Post-processing the synthetic tail particles to assign realistic observational properties, we infer that Segue 3 would have close to 25 extra-tidal members with G ≤ 23, concentrated ≲1.°33 from the center of the cluster. The 11 candidate extratidal members identified by Fadely and collaborators are comparable in number, but significantly closer to the cluster center (d ∼ 4′) than these simulations predict. This analysis demonstrates the difficulty of identifying extratidal stars in the Milky Way's halo clusters, even in deep photometric surveys.

Impact of the use of seawater on acid mine drainage from mining wastes

The copper mining industry is vital in the transition to fossil-free power for achieving sustainability worldwide, which is mainly based on the exploitation of copper sulfide ores. However, the mineral processing produces a large volume of mine tailings, and their quantity is almost equal to the ores treated. Acid mine drainage (AMD) is a challenging environmental problem caused by tailing disposal when it is not well managed. In addition, several copper mining companies employ seawater in their process because they operate in arid or semi-arid regions, including northern Chile, southern Peru, and Australia. For copper sulfide mineral processing, the use of seawater is not a limitation in the flotation process, and positive and negative effects appear compared to using fresh water. However, there are no records in the literature on the impact of seawater on the generation of AMD, considering that it is a solution with a high concentration of different ions. This study aims to evaluate the chemical stability of synthetic tailings with and without seawater by kinetic tests using seven humidity cells. The synthetic tailings are mixtures of pyrite, chalcopyrite, arsenopyrite, and quartz. The main results show that the AMD generation kinetics after 25 weeks of testing humidity cells leached with distilled water (acid-generating cells) behaved differently than the humidity cells leached with seawater (non-acid-generating cells). After 25 weeks of testing, the acid-generating humidity cells had a pH value below 2.26, while the non-acid-generating humidity cells had a pH value above 7. It was also shown that fine-particle-size granulometry generates AMD faster than coarse-particle-size granulometry. Finally, the sulfide minerals’ ion dissolution occurred when the humidity cells were leached with distilled water and not when leached with seawater. The results show that using non-desalinized seawater in copper ore processing can help prevent AMD due to the buffering effect of seawater and the protection coat formed by oxyhydroxide and/or bivalent cations.

Investigation of the Attenuation and Release of Cu2+ Ions by Polymer-Treated Tailings

This study investigated the attenuation and release behaviour of copper ions using a standard kaolin-silt slurry as the synthetic tailings in a high solids/high salinity application before and after inline flocculation. A homogenous, synthetic tailings slurry was prepared in a 0.6 M NaCl solution and treated in a low-shear mixer by adding Magnafloc® 336 flocculant. Following the evaluation of morphological properties of both the untreated (UT) and polymer-treated tailings (PT), identical equilibrium tests were performed via the bottle-point method constant concentration technique. The maximum copper ions uptake capacity of polymer-treated tailings was 25% more than the untreated slurry at the equilibrium state in a chemisorption process in which the ions had the capability of binding onto one location on the sorbent, which could be influencing other binding sites on the same sorbent. Polymer treatment resulted in a highly porous structure that exhibited an increased capacity to adsorb and retain copper ions compared to the UT materials. This behaviour indicates the strong binding between the copper ions and active site of the treated tailings particles with greater capability of this material for preserving heavy metal ions within their structure across a wide pH range (2–10) compared to the UT materials. The results advance the fundamental understanding of how inline flocculation can considerably improve the sorption capacity of high solids/high salinity tailings favouring potential long-term rehabilitation purposes at mine closure and the role of sorption and desorption of heavy metal ions’ behaviour play to achieve this goal.

The Impact of Residual Dispersant on the Flocculation and Sedimentation of Synthetic Tailings in Seawater

Dispersants under certain conditions favor the flotation of molybdenite in seawater; however, it is not clear if the entrainment of residues to the thickening stage can compromise the quality of the clarified water. In this work, the impact of small concentrations of sodium hexametaphosphate (SHMP) on the flocculation and sedimentation of synthetic tailings containing kaolinite, muscovite, and quartz in seawater is evaluated. The flocculant polymer is a high-molecular-weight polyacrylamide, and the pH is alkaline. The results are auspicious for mineral processing. On the one hand, the impact of SHMP is not entirely negative and can be lessened by limiting entrainment, which is good for copper and molybdenum ore processing. On the other hand, if the small increase in turbidity generated by the SHMP is tolerated, it is possible to expect improved settling speeds. Without SHMP, large but light agglomerates are formed. With SHMP, smaller but denser aggregates are formed, settling faster, and minute aggregates increase turbidity. The underlying mechanism derives from the competition between SHMP and polymer chains for the cations in solution; the result is a greater repulsion between the chains, which leads to greater repulsion and thus dispersion of smaller flocculant coils. The study shows that SHMP in concentrations of 1 to 3 kg/t is perfectly acceptable. The results represent an advance in the understanding of SHMP interactions with polymers and minerals in water clarification, which should be of interest to the industry whose sustainability in some regions depends on closing the water cycle.

The impacts of high salinity and polymer properties on dewatering and structural characteristics of flocculated high-solids tailings

In seeking to better understand the inline flocculation technique for enhanced water recovery from concentrated fine-particle suspensions, polymers of different molecular weight (MW) and chemistry were used to treat a synthetic tailings slurry in a low-shear mixer for continuous flocculation under controlled conditions. The effects of dissolved salts in the slurry and polymer solution make-up water on dewatering performance were evaluated for conventional acrylamide/acrylate copolymers (BASF Magnafloc® products) and an alternative functional chemistry polymer (BASF Rheomax® DR 1050). The properties of the separated liquid and solid phases were examined to understand the impacts of salinity and polymer type on the formation of rapidly dewatering flocculated material. Higher concentrations of NaCl (0.006–0.6 M) and CaCl2 (0.006–0.06 M) salts in the unflocculated slurries formed larger coagulated structures, with focussed beam reflectance measurement (FBRM) showing greater pre-aggregation for the divalent salt. NaCl slurries show edge-to-edge (EE) and edge-to-face (EF) inter-particle associations that are open and easily disrupted while more compact face-to-face (FF) contacts are observed in CaCl2 slurries. For concentrated NaCl slurries, the dosing of medium-to-high MW polymers is generally preferred to maximise net water recovery, with the implication being that bridging mechanisms are still at play in high solids applications. In calcium-enriched slurries, the lower MW conventional copolymer gave comparatively better water returns than the other polymers when applied under low shear conditions, highlighting quite distinct aggregation processes compared to low solids flocculation. These results provide insight on the fundamental complexity of the ionic strength dependence of high solids-high dosage tailings flocculation, towards informing reagent polymer dosing and offering greater flexibility for end-of-pipe dewatering schemes.

Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management.

Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.

Temporal evolution of the structure of tailings aggregates flocculated in seawater

Mineral processing produces large volumes of dilute tailings that are flocculated and thickened, returning water to the process. The drive towards more sustainable processing has seen seawater considered to replace fresh water usage and an increased focus on how flocculation conditions can influence the fractal-like aggregates formed. The fragility of such structures and the likelihood that they change with time makes their study challenging.A synthetic tailings slurry of quartz and kaolin in seawater was flocculated at different mixing times and flocculant dosages, with aggregate size monitored over time by focused beam reflectance measurement (FBRM) and hindered settling rates determined after set reaction times. A model relating hindered settling rate to size as estimated by FBRM was used to derive an aggregate fractal dimension (Df) at each time. With flocculation at typical tailings solids concentrations rapid, aggregate breakage will normally dominate after very short reaction times. Under mild mixing conditions, settling rates are higher than expected from sizes measured in real time due to aggregate growth continuing after mixing ceases, leading to inflated Df estimates. An apparent decline in Df under more intense mixing was consistent with an increased presence of high aspect ratio (low effective porosity) aggregate fragments, supported by in situ aggregate imaging at different reaction times. In contrast, the observed trends for a reduction in Df with mixing intensity and an increase with dosage are both thought to represent the expected aggregate structure changes for the synthetic tailings.While estimating aggregate structural properties by relating FBRM sizes to settling rates can offer useful insights, it is important to recognise the aggregation state observed by FBRM under mixing applied to induce flocculation may differ from that which exists during hindered settling. Values of Df derived in this manner must therefore be viewed with caution.

A new statistically-based methodology for variability assessment of rheological parameters in mineral processing

If variability of input data for rheological measurements is not adequately included, their associated uncertainty and subsequent modelling can be underrated. Mineral pulp rheology determination is commonly done through triplicate tests, with such variability reported as multiples of a standard deviation, with the potential for underestimation. In the present work, a novel statistically-based methodology for the estimation of uncertainty in the rheological characterization of mineral suspensions —and other parametric models— is proposed. From the variability of the experimental measurements and the analytical propagation of errors, a set of rheological profiles are generated using Monte Carlo simulations within a variability frame. The corresponding inverse problem for curve-fitting is solved individually, resulting in distributions of fitted parameters, which were statistically-analyzed to obtain representative values for both the parameter and its true variability. The methodology proposed herein has been used to explore the applicability and limitations of the Herschel-Bulkley and Bingham models under specific experimental and data analysis protocols, where the relevance of including low-shear-rate measurement points or yield stress measurements using alternative methods is exposed. Additionally, we present a case study on the effect of the concentration of NaCl on the rheological response of synthetic tailings consisting of quartz suspensions doped with kaolinite, bentonite and kaolinite-bentonite blends, using the proposed methodology with a concentric cylinder rheometer. Results show predominantly decreasing trends in yield stress as salt concentration increases, with non-monotonical behavior and strongest variability associated to the quartz-bentonite blend.

Seawater flocculation of clay-based mining tailings: Impact of calcium and magnesium precipitation

In areas where access to water of good quality is limited, the use of seawater in mineral processing can be an option. However, the dewatering of waste tailings is adversely affected, particularly when this follows processing at higher pH. The flocculation response of a synthetic clay-based tailings in seawater to different pH conditions was examined in detail, focusing on conditions promoting precipitation of the divalent cations present. Flocculated aggregate growth and breakage during turbine mixing were monitored in-situ in terms of chord length distributions (by focused beam reflectance measurement) and aggregate image capture, with the resultant hindered settling rates also determined. It was found that flocculation in seawater was substantially impaired at pH values greater than 10.3 due to the precipitation of magnesium species. The addition of the precipitated phase to the synthetic tailings increases both the surface area exposed to flocculant and the number of particles or micro-aggregates then needing further aggregation to attain acceptable settling rates. The direct use of seawater in processing operations without resorting to full desalination does not necessarily have detrimental impacts on tailings flocculation and thickening, provided the operation is conducted at a pH that prevents the precipitation of magnesium present within the process liquors.

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.

Consolidated Undrained Shear Behavior of Synthetic Waste Rock and Synthetic Tailings Mixtures

The objective of this study was to evaluate the effects of mixture ratio (R) and synthetic tailings composition (i.e., particle-size distribution) on the undrained shear behavior of mixed synthetic waste rock and tailings (S-WR&T). Crushed gravel was used as a granitic waste rock (GWR), and mixtures of sand, silt, and clay were used to create average synthetic tailings (AST) and fine synthetic tailings (FST). Mixtures of S-WR&T were prepared to simulate coarse-dominated, optimal, and fine-dominated mixtures. Testing was conducted in consolidated undrained triaxial compression at target effective confining stresses of 10, 50, and 100 kPa. Coarse-dominated S-WR&T mixtures exhibited comparable shear behavior to pure GWR. Fine-dominated S-WR&T mixtures exhibited shear behavior that was more similar to pure synthetic tailings. However, an analysis of the undrained shear response indicated that the presence of GWR in fine-dominated S-WR&T mixtures can transition undrained flow behavior of pure synthetic tailings to limited-flow or no-flow behavior that is representative of GWR. The AST mixture prepared at optimal mixing conditions yielded an effective stress friction angle (φ′t) = 48°, and fine-dominated mixtures of AST yielded φ′t = 44°. The fine-dominated mixtures for FST yielded φ′t ranging from 32° to 38°, whereby φ′t increased with an increase in the amount of GWR in the mixture.

Discussion of “Unconfined Compressive Strength of Synthetic and Natural Mine Tailings Amended with Fly Ash and Cement” by Mohammad H. Gorakhki and Christopher A. Bareither

Discussion of “Unconfined Compressive Strength of Synthetic and Natural Mine Tailings Amended with Fly Ash and Cement” by Mohammad H. Gorakhki and Christopher A. Bareither

Closure to “Unconfined Compressive Strength of Synthetic and Natural Mine Tailings Amended with Fly Ash and Cement” by Mohammad H. Gorakhki and Christopher A. Bareither

Closure to “Unconfined Compressive Strength of Synthetic and Natural Mine Tailings Amended with Fly Ash and Cement” by Mohammad H. Gorakhki and Christopher A. Bareither

Field-based accounting of CO2sequestration in ultramafic mine wastes using portable X-ray diffraction

Carbon mineralization, the sequestration of carbon within minerals, presents one method through which we could control rising levels of anthropogenic carbon dioxide (CO) emissions. The mineral wastes produced by some ultramafic-hosted mines have the ability to sequester atmospheric CO via passive carbonation reactions. Carbon accounting in mine tailings is typically performed using laboratory-based quantitative X-ray diffraction (XRD) or thermogravimetric methods, which are used to measure the abundances of carbonate-bearing minerals such as hydromagnesite [Mg(CO)(OH)·4HO] and pyroaurite [Mg Fe23+ $\text{Fe}^{3+}-{2}$ (CO)(OH)·4HO]. The recent development of portable XRD instruments now allows for the characterization and quantification of minerals in the field. Here we assess the feasibility of using a portable XRD instrument for field-based carbon accounting in tailings from the Woodsreef Chrysotile Mine, New South Wales, Australia. Modal mineralogy was obtained by Rietveld refinements of data collected with an inXitu Terra portable XRD. The Partial Or No Known Crystal Structures (PONKCS) method was used to account for turbostratic stacking disorder in serpentine minerals, which are the dominant phases in tailings from Woodsreef. Weighed mixtures of synthetic tailings were made to evaluate the precision and accuracy of quantitative phase analysis using the portable instrument. An average absolute deviation (bias) of 8.2 wt% from the actual composition of the synthetic tailings was found using the portable instrument. This is comparable to the bias obtained using a laboratory-based diffractometer (9.6 wt% absolute) and to the results from previous quantitative XRD studies involving serpentine minerals. The methodology developed using the synthetic tailings was then applied to natural tailings samples from Woodsreef. Surface crusts forming on the tailings pile were found to contain hydromagnesite (∼5.8 wt%) and pyroaurite (∼2.1 wt%). Comparable results were obtained using the laboratory-based instrument and these results are expected to have similar biases to the analyses of the synthetic tailings. These findings demonstrate that portable XRD instruments may be used for field-based measurement of carbon sequestration in minerals in engineered and natural environments.

A contribution to improve the calculation of the acid generating potential of mining wastes

Mine wastes from sulfide-bearing ore extraction and processing are often stored at the surface of mine sites and could generate mine drainage. Prediction tests are completed to predict the water quality associated with the deposition of mining wastes. Static tests can quickly assess the acid-generating potential (AP) and the neutralization potential (NP). Whereas some studies recommend to take into account a mineral reactivity factor for the NP determination, the reactivity rates of acidifying minerals are not considered in the AP calculation. The aim of this study is to bring contribution to the improvement of the static test determination by adding kinetic factors in the AP determination. Eight sulfides (pyrite, Ni-pyrite, pyrrhotite, Ni-pyrrhotite, chalcopyrite, galena, sphalerite, arsenopyrite) and a sulfosalt (gersdorffite) were separately submitted to kinetic tests in modified weathering cells. This test was selected for its rapidity of results and for the low amount of material used, as it is somewhat difficult to obtain pure minerals samples. Five synthetic tailings were composed by mixing pure sulfides in various proportions and submitted to the same kinetic tests. The oxidation rates of synthetic tailings were compared with the weighted combined oxidation rates of individual pure sulfides. The oxidation rates of the synthetic tailings calculated from those of pure sulfides are within the same order of magnitude than those obtained through the kinetic experiments. The AP of synthetic tailings were calculated according to standard equations of the literature and compared with the new method.

Hydraulic Conductivity of Fly Ash-Amended Mine Tailings

The objective of this study was to evaluate the effect of fly ash addition on hydraulic conductivity (k) of mine tailings. Mine tailings used in this study were categorized as synthetic tailings and natural tailings; two synthetic tailings were developed via blending commercially-available soils and natural tailings were collected from a garnet mine located in the U.S. Two fly ashes were used that had sufficient calcium oxide (CaO) content (17 and 18.9 %) to generate pozzolanic activity. Hydraulic conductivity was measured on pure tailings and fly ash-amended tailings in flexible-wall permeameters. Fly ash was added to mine tailings to constitute 10 % dry mass of the mixture, and specimens were cured for 7 and 28 days. The influence of fly ash-amendment on k of mine tailings was attributed to (1) molding water content and (2) plasticity of the mine tailings. Tailings that classified as low-plasticity silts with clay contents less than 15 % exhibited a decrease in k when amended with fly ash and prepared wet of optimum water content (w opt ). Tailings that classified as low-plasticity clay exhibited a one-order magnitude increase in k with addition of fly ash for materials prepared dry or near w opt . The decrease in k for silty tailings was attributed to formation of cementitious bonds that obstructed flow paths, whereas the increase in k for clayey tailings was attributed to agglomeration of clay particles and an overall increase in average pore size. The results also indicated that the effect of curing time on k is more pronounced during the early stages of curing (≤7 days), as there was negligible difference between k for 7 and 28-days cured specimens.

Supramolecular Ligands for Histone Tails by Employing a Multivalent Display of Trisulfonated Calix[4]arenes.

Post-translational modification of histone tails plays critical roles in gene regulation. Thus, molecules recognizing histone tails and controlling their epigenetic modification are desirable as biochemical tools to elucidate regulatory mechanisms. There are, however, only a few synthetic ligands that bind to histone tails with substantial affinity. We report CA2 and CA3, which exhibited sub-micromolar affinity to histone tails (especially tails with a trimethylated lysine). Multivalent display of trisulfonated calix[4]arene was important for strong binding. CA2 was applicable not only to synthetic tail peptides but also to endogenous histone proteins, and was successfully used to pull-down endogenous histones from nuclear extract. These findings indicate the utility of these supramolecular ligands as biochemical tools for studying chromatin regulator protein and as a targeting motif in ligand-directed catalysis to control epigenetic modifications.

A quantitative approach for the estimation of the “fizz rating” parameter in the acid-base accounting tests: A new adaptations of the Sobek test

Acid-base accounting (ABA) is a widely used technique for the determination of the acid generating potential of geological material. It consists of a screening method where the neutralization potential (NP) and the acid-generating potential (AP) of rock sample are determined. Among the first ABA test is the one proposed by Sobek et al. (1978) and it is the most used test in North America. AP is calculated based on the sulfide sulfur content in the sample. However, NP is assessed by using acid-base titration with some limits. In fact, discrepancies in results obtained for a same sample by Sobek test were pointed out by several authors depending on fizz rating, on sample mineralogy (iron-bearing carbonates and Fe–Al-silicates), on the titration method, or the laboratory practitioner. Thus, some authors have proposed modifications of the Sobek test to improve the test reliability and the resulting waste classification. Nevertheless, no modified method has been able alone to overcome all error sources. The subjectivity of fizz rating, which is performed to determine the concentration and volume of hydrochloric acid to be added to a sample for neutralizing minerals digestion and subsequent NP determination, remains the main limit of the test. So, the aim of this study is to develop a quantitative approach, replacing the subjective visual fizz, to calculate the exact volume of hydrochloric acid (HCl) needed to digest the entirety of Fe–Mn–Mg-carbonates that give to a sample their main neutralizing potential. Then, a new adaptation of the Sobek test, based on the quantitative Fizz, is proposed in this paper. Testings were conducted on samples prepared by mixing pure minerals in well known quantity mimicking concentrator tailings (here named synthetic tailings). The obtained NPs by the quantitative fizz based method are well correlated with the theoretical NP obtained by the mineralogical Paktunc method. This new Sobek test adaptation requires knowledge of detailed sample mineralogy or at least the inorganic carbon content. If such information is not available, alternative digestion methods are proposed giving results which are also well correlated with the Paktunc method. The synthetic tailings were subjected to a kinetic test to evaluate their acid-generating potential. The NP values obtained by the quantitative fizz based methods, and resulting sample classifications, are consistent with kinetic test predictions demonstrating the effectiveness of the Sobek test refinement suggested by the authors to enhance the confidence of acidity potential classification.