Alkaline Materials Research Articles

Alkali-activated slag & fly ash as sustainable alternatives to OPC: Sorptivity and strength development characteristics of mortar

One approach to decreasing the environmental footprint of the construction industry is to replace ordinary Portland cement (OPC) with recycled slag and fly ash activated using alkaline materials. This article presents the outcomes of an experimental study that evaluated water absorption characteristics and strength development of mortar that uses blends of alkali-activated ASTM class F slag and fly ash binders. Mortar mixes were developed using three binder combinations: 100% slag and no fly ash (S1F0), 75% slag + 25% fly ash (S3F1), and 50% slag + 50% fly ash (S1F1). Slag and fly ash binders were activated using NaOH solution with molarity ranging from 10 mol/L to 16 mol/L mixed with sodium silicate solution. Two sets of samples were created, one set was immersed in an acidic medium after casting, which represented a closed environment, and the second was left in the lab exposed to air until the test day. For mortar cured in a closed system, the highest strength development during the first seven days after casting occurred in S1F0 mortar followed by S3F1, then S1F1. The observation indicates strength development is dominated by the fast reactivity of slag during the first 7 days. The pattern is similar for all NaOH activator concentrations evaluated in this study. Mortar samples with high slag content (S1F0 and S3F1) that were cured in air experienced a decrease in strength during the 28–90 day curing phase as the strength at the age of 90 days decreased relative to the strength at 28 days. However, S1F1 gained strength during the 28–90 day phase when NaOH molarity was the highest (16 mol/L). This is due to the dissolution and activation of fly ash at high solution alkalinity which contributed to the continued increase in strength. A strong linear correlation between the square root of time (t0.5) and water absorption existed in all activated mortars evaluated in the study, except for mortar samples prepared using NaOH with high concentration and the highest ratio of Na2SiO3/NaOH. Therefore, alkali-activated slag-based mortars share similar water capillary absorption characteristics with conventional cement-based mortar. It was found that increasing the NaOH concentration increases the global warming potential (gwp) and that the mix with the least environmental impact was the S1F1 developed using the lowest NaOH concentration of 10 mol/L and 50% fly ash.

Combined application of strong alkaline materials and specific organic fertilizer accelerates nitrification process of a rare earth mining soil

The extensive usage of ammonium sulfate as the leaching agent to extract rare earth elements led to widespread ammonia nitrogen (NH4+-N) pollution in the tailing soils of ion-adsorbed rare earth deposits in southern China. However, the cost-effective technologies to tackle with the long-term retention of NH4+-N in the rare earth mining soil have been largely unresolved. In this study, we developed a cost-effective approach to activate soil nitrification by the co-application of alkaline materials and organic fertilizer. The co-application of 0.3 % of organic fertilizer and 0.1 % ∼ 0.2 % of CaO or MgO or Mg(OH)2 stimulated a soil NH4+-N decrease rate of 2.01–7.58 mg kg−1 d−1 and a soil NO3−-N accumulation rate of 1.56–7.09 mg kg−1 d−1. Noting that only if the soil pH was elevated to 7.81–9.00, the NH4+-N decrease rate and NO3−-N accumulation rate were dependent on the proton consumption capacity of the alkaline materials. The application of CaCO3 could not stimulate soil nitrification possibly due to the soil pH was uncapable to be elevated to above 7.68. The qPCR, amplicon sequencing, and nitrification inhibitor batch incubation results demonstrated that organic fertilizer supplied active ammonia-oxidizing bacteria Nitrosomonas europaea. The proliferation of Nitrosomonas europaea in the alkaline materials and organic fertilizer co-applied soil was responsible for the soil nitrification. Furthermore, the application of commercial denitrifying bacteria inoculum promoted the removal of accumulated NO3−-N. The findings of this study provide a lost-cost technology to remove NH4+-N from the rare earth mining soil.

Role of CO2 in enhancing geopolymer properties formulated with fluidized bed combustion ash

Fluidized bed combustion coal ash was used together with conventional coal ash and alkaline materials to synthesize geopolymer cement. The production process was performed in a carbon dioxide-rich environment to integrate carbon dioxide into the cement. The presence of carbon dioxide was found to enhance the formation of crystalline carbonates during the hydration reaction yielding an enhanced geopolymer matrix with improved binding characteristics. The non-crystalline (metastable) carbonates formed undergo crystallization processes that complement the hydration reactions, and yield carbonate with beneficial binding effects. Experimental optimization was designed and implemented to select the desired formulation of raw materials for achieving high levels of carbon capture and engineering properties. The optimized formulation produced a geopolymer cement with 7.4 wt% CO2 content, which produced concrete materials with a flow table of 68 cm, an initial set time of 34 min, and 28-day compressive strength reaching 28.2 MPa with acceptable residual compressive strength.

Carbon capture and utilization: More than hiding CO2 for some time

Carbon capture and utilization: More than hiding CO2 for some time

Atmospheric Deposition around the Industrial Areas of Milazzo and Priolo Gargallo (Sicily-Italy)-Part A: Major Ions.

The chemical composition of rainwater was studied in two highly-industrialised areas in Sicily (southern Italy), between June 2018 and July 2019. The study areas were characterised by large oil refining plants and other industrial hubs whose processes contribute to the release of large amounts of gaseous species that can affect the chemical composition of atmospheric deposition As in most of the Mediterranean area, rainwater acidity (ranging in the study area between 3.9 and 8.3) was buffered by the dissolution of abundant geogenic carbonate aerosol. In particular, calcium and magnesium cations showed the highest pH-neutralizing factor, with ~92% of the acidity brought by SO42- and NO3- neutralized by alkaline dust. The lowest pH values were observed in samples collected after abundant rain periods, characterised by a less significant dry deposition of alkaline materials. Electrical Conductivity (ranging between 7 µS cm-1 and 396 µS cm-1) was inversely correlated with the amount of rainfall measured in the two areas. Concentrations of major ionic species followed the sequence Cl- > Na+ > SO42- ≃ HCO3- > ≃ Ca2+ > NO3- > Mg2+ > K+ > F-. High loads of Na+ and Cl- (with a calculated R2 = 0.99) reflected proximity to the sea. Calcium, potassium, and non-sea-salt magnesium had a prevalent crustal origin. Non-sea salt sulphate, nitrate, and fluoride can be attributed mainly to anthropogenic sources. Mt. Etna, during eruptive periods, may be also considered, on a regional scale, a significant source for fluoride, non-sea salt sulphate, and even chloride.

Mechanochemical treatment of hexachlorobenzene-contaminated soil with additives.

The use of mechanochemistry for the remediation of hexachlorobenzene (HCB)-contaminated soil was investigated. Additives such as alkaline materials, neutral materials, natural minerals, and solid waste were studied to explore their effect on the degradation of hexachlorobenzene in soil with single or combined addition by mechanochemical method. The best combination of materials were determined based on HCB destruction percentage by considering the impact on soil quality, the treatment cost, and the availability of additives. Scanning electron microscope (SEM) images and X-ray photoelectron spectrometer (XPS) analysis were conducted for the mechanism studies. The combination of albite and ferric oxide (Fe3O4) was found to achieve the best performance in the degradation of HCB with the destruction percentage from 74.3 to 92.5% after 2-h and 6-h reaction, respectively. The developed fracture structure and complex compositions of albite provided abundant reaction sites for mechanochemical degradation of HCB in soil.

Carbonation Resistance of Mortar Mixed with Electrolysis Alkaline Aqueous Solution and Blast Furnace Slag

Cement production is the primary source of global CO2 emissions in the construction industry. Blast furnace slag (BFS) has been examined as a potential substitute for cement to reduce CO2 emissions. In addition, this substitution increases the long-term strength and improves the chemical resistance of mortar. However, a glassy film is formed on the surface of BFS while it is generated as a byproduct, lowering the initial strength of mortar. Notably, this film is destroyed in an alkaline environment. Thus, several studies have used solutions with various alkali activators. However, alkali activators are unsafe, as they are strong alkaline materials, and have low economic efficiency. This study experimentally improved the initial hydration reactivity of a mortar containing BFS as a substitute for cement, thereby improving its initial strength. We observed an increase in carbonation resistance. In addition, this study focused on evaluating the compressive strength and carbonation resistance of mortar prepared using BFS and alkaline water obtained from the electrolysis of a K2CO3 electrolyte. Results show that alkali-activated mortar using an electrolyzed alkaline aqueous solution has higher strength and contains more hydration products than that using conventional mixing water.

Activating soil nitrification by co-application of peanut straw biochar and organic fertilizer in a rare earth mining soil

The intensive mining activities to extract rare earth elements from ion-adsorption rare earth deposits have introduced massive amounts of ammonium into the tailing soils in southern China. Compared to the ubiquitous soil nitrification in cropland, forest, and grassland soils, however, there is no feasible strategy to alleviate the ammonium contamination in tailing soil. Herein, the feasibility to remove ammonium by adding ammonium adsorbents (e.g., biochar, activated carbon, and zeolite), alkaline materials, and organic fertilizer to the rare earth mining soil was explored. The amendment of rice straw biochar, activated carbon, or zeolite in combination with CaCO3 and organic fertilizer showed no significant effect on ammonium removal due to their limited capacity to elevate soil pH. However, the co-application of peanut straw biochar (PSBC), CaCO3, and organic fertilizer activated both the ammonia volatilization and soil nitrification processes. Specifically, the three components functioned as follows: organic fertilizer supplied active ammonia-oxidizing bacteria (AOB); PSBC stimulated AOB proliferation by elevating soil pH above 7.75; CaCO3 ameliorated soil acidity and reduced the lag time for activating soil nitrification. The soil ammonium removal and nitrate accumulation rates were positively correlated to the acid neutralization capacity of PSBC prepared at 400 °C–800 °C. The qPCR and microbial community analysis results indicated that Nitrosomonas europaea was the dominant AOB that was responsible for enhanced soil nitrification. Our findings pave the way for developing cost-effective strategies to remediate ammonium contamination in rare earth mining soils.

Extracellular Enzyme Patterns Provide New Insights Regarding Nitrogen Transformation Induced by Alkaline Amendment of Acidic Soil

Nitrogen (N) availability is generally a limiting factor in highly acidic soil, which could be improved by amending these soils with alkaline materials. Soil extracellular enzyme activity (EEA) plays an important role in N transformation; a current knowledge gap is how this occurs in acidic soils amended with alkaline material. The present 45-day incubation experiment was designed to examine the effects of different amounts of alkaline materials (urea and/or calcium–silicon–magnesium–potassium fertilizer (CSMP)) on N transformation. The results show that soil pH significantly increased after the CSMP amendment (1.2 units) and increased soil net N mineralization (Rmin), net nitrification (Rnit) rates, and net ammonification (Ramo) rates. CSMP amendment changed the different soil EEA but with differing or opposing effects, e.g., Rnit was positively correlated with the activities of L-leucine aminopeptidase, β-xylosidase, α-glucosidase, and N-acetyl-β-glucosaminidase but negatively correlated with β-1, 4-glucosidase and β-cellobiosidase. A machine learning analysis indicated that the best predictor for Rmin and Ramo was soil pH, and for Rnit, it was nitrate. The results of the present study improve our understanding of N availability in acidic soils amended with materials to control soil pH. Such knowledge could lead to more bespoke nutrient management planning at the field scale, leading to better agronomic and environmental outcomes.

Potential of granular complexes of lime and montmorillonite for stabilizing soil cadmium and the underlying mechanisms

Cadmium (Cd) contaminated soils were widely remediated by alkaline materials in powder, while the effects of granular materials are still unknown. This study was conducted to prepare granular materials based on hydrated lime and montmorillonite with ratios of 1:1, 1:2, and 1:3 (LM1, LM2, and LM3); their effects and mechanisms on stabilizing Cd in hydroponic, pot, and field conditions were further explored. The results showed that powdery materials caused intense pH elevations within 30–60 min and dissolved-Cd reductions within 8–100 min. However, granular materials significantly delayed these effects; the highest solution pH and lowest dissolved-Cd occurred after 250 min. The LM1 granules induced a much higher reduction of dissolved-Cd (99.8%) than that in the LM2 (53.6%) and LM3 granules (14.3%) due to the generation of more cadmium carbonate precipitates. Additionally, the soil pH gradually decreased after an intense elevation induced by powdery materials, but the LM1 granules maintained the soil pH at approximately 7.0, resulting in a lower level of CaCl2-extractable Cd (0.03 mg kg−1) than the LM1 powder (0.22 mg kg−1) after 30 d of cultivation. Similar to lime powder, a small spatial variation (Std. of 3.45) of DGT (diffusive gradient in thin films) extractable Cd in soil profile was observed in the LM1 granules, revealing a homogeneous stabilization effect induced by the LM1 granules. Accordingly, the LM1 granules induced a higher reduction in brown rice Cd (50.9%) than that in the LM1 powders (35.1%). Thus, the granular material of hydrated lime and montmorillonite (1:1) h the potential to replace lime powder in the remediation of Cd-contaminated field.

Acidification potential of geological materials in a coal mining area in southern Brazil

Acid mine drainage (AMD) is considered the major environmental hazard in coal mined areas. Characterizing the acidification potential of materials from representative geological drilling columns in coal pre-mined areas allows predicting the quality of a future constructed minesoil in post-mining areas. In this sense, acidification potential and neutralization potential quantifications enable selecting materials of the geological column that could be used to naturally neutralize acidifying materials and quantify alkaline materials for acidity correction. Therefore, this study aimed to estimate the probable composition of the constructed soil and its predisposition to cause acid mine drainage, and also estimating their potential to increase acidity in the soils and surface and subsurface waters of post-mining areas. The study was conducted in a coal mining area located in Southern Brazil. Geological material sampling included soil and rocks from six drill holes from the geological column representative of future coal mining areas. The mineralogical analysis was conducted using X-ray diffraction for the complete sample in powder form. The basic materials characterization was carried with chemical analyses: pH of water; pH of CaCl2; exchangeable cations; potential acidity. Results indicate the acidification general tendency in future constructed soils, and that control measures to prevent acid mine drainage generation must be adopted. In this regard, the use of BL and Coal (S2) seams is recommended, since they present an extremely high acidification potential. Furthermore, the controlled placement of sandstone layer with high potential acidity, and its treatment with carbonate materials addition is also recommended. Data regarding soil layers with high sum and base saturation, and the presence of smectite, typical of a Mollisol in F530 drill, reveal to environmental recovery teams the necessity of adapting to another soil condition. This condition must be chemically more fertile, but also physically harder to deal with than the Ultisol normally found in the current mining area.

Waste resource utilization: Spent FCC catalyst-based composite catalyst for waste tire pyrolysis

• Composite FCC catalysts were used to improve waste tire pyrolysis product yields. • CaO or heavy oil could enhance the catalytic pyrolytic effect of FCC catalysts. • Heavy oil enhances interactions between the spent FCC catalysts and waste tires. • CaO decreases the sulfur contents of the final tire pyrolysis oil products. • Proposed composite catalysts extend the application of pyrolysis to waste tires. Waste tires are complex organic materials composed of various rubbers and fillers. Spent fluid catalytic cracking (FCC) catalysts cannot efficiently catalyze the pyrolysis of all organic components in waste tires. In this study, we attempted to improve the yield and quality of products obtained from the pyrolysis of waste tires. To this end, we prepared two composite catalysts (i.e., spent FCC catalysts + heavy pyrolysis oil and spent FCC catalysts + calcium oxide) with spent FCC catalysts as the main component, and studied their synergistic effects on the catalytic pyrolysis of the tires. In this study, the composite catalyst improved the recovery volume of the pyrolysis oil at 205 and 360 °C and increased the BTEX content in the oil by 14.7% and 8%, respectively. The experimental results showed that the heavy oil component in the composite catalyst enhanced interactions between the spent FCC catalysts and waste tires, thereby improving the yield and quality of tire pyrolysis oil (TPO). The alkaline material in the composite catalyst played a role in sulfur fixation and reduced the sulfur content of the TPO. The application of spent FCC catalysts to waste tire pyrolysis can meet the demand for low-cost catalysts for waste tires and improve the quality of the resulting TPO. Our findings collectively reflect the economic and social benefits of using composite catalysts for waste tire pyrolysis.

Effects of residual carbon on the synthesis of 1.1 nm tobermorite from coal gasification ash

Coal gasification ash (CGA) is a solid waste produced by coal gasification. It can be used to produce autoclaved building materials because tobermorite, the main hydration product in such materials, can be formed from CGA and calcium oxide (CaO). In this study, tobermorite was prepared through the hydrothermal treatment of CGA. Given that residual carbon is usually present to some degree in CGA, its effects on the formation of tobermorite were specifically studied using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption–desorption tests. The results showed that tobermorite can be prepared from a CGA/calcium oxide mixture at 160°C without additional alkaline material. However, residual carbon can retard the transformation of calcium silicate hydrate into tobermorite and thus increase the required formation temperature while prolonging the formation time. With an increase in the residual carbon content, the morphology of the resulting tobermorite changes from needle-like and plate-like to irregular, which may also have a detrimental effect on the mechanical properties of the material.

Waste control by waste: A comparative study on the application of carbide slag and quicklime in preparation of phosphogypsum-based ecological restoration materials

This study explored the potential applications of quicklime and carbide slag in the preparation of phosphogypsum (PG)-based ecological restoration materials. The migration and transformation behavior of large amounts of soluble impurities (PO43−, F−, NH3-N, Cr6+, Mn, and Cu) in PG were studied. A solid–solid phase reaction was innovatively employed, and PHREEQC was used as the simulation software to investigate the solidification/leaching mechanism of pollutants in PG treated with different amounts of alkaline materials. The results showed that acid–base condition is a dominant factor controlling the migration and transformation of P, F, NH3-N, and heavy metals. The addition of a small amount of quicklime or carbide slag to PG considerably improved its pH. Quicklime and carbide slag exhibited remarkable stabilization effects on PO43−, F−, Cr6+, and Mn, and the leaching concentration of water-soluble fluorine and NH3-N in PG added with quicklime decreased substantially. In general, when preparing PG-based ecological restoration materials, the addition of carbide slag exhibited a stronger acid buffering capacity, pollutant stabilization capacity, and potential nutrition than that of quicklime. In particular, the use of carbide slag instead of quicklime in PG treatment can reduce the cost of PG treatment by approximately $1.3–1.5 per ton.

Chemical Stabilization Used to Reduce Geogenic Selenium, Molybdenum, Sulfates and Fluorides Mobility in Rocks and Soils from the Parisian Basin

Rocks and soils excavated from civil works frequently present high concentrations of naturally occurring leachable (oxy-)anions. This situation raises concerns regarding the potential transfer of contaminants to groundwater in a storage scenario. This study was carried out to give practical insights on the ability of various stabilizing agents to reduce molybdenum (Mo), selenium (Se), fluorides and sulfates mobility in four types of naturally contaminated excavated materials. Based on standardized leaching tests results, Mo and Se were effectively immobilized after zero valent iron or iron salts additions. Although alkaline materials were found to effectively reduce fluorides and sulfates mobility, their addition occasionally caused a subsequent increase in Mo and Se leaching due to pH increase. None of the reagents tested allowed a simultaneous immobilization of all (oxy-)anions sufficient to reach regulatory threshold values. The remaining difficulties were related to: (i) sulfates leaching from gypsum-rich samples, (ii) fluorides leaching from clayey samples and (iii) Mo and sulfates mobility from tunnel muck. Altogether, the study revealed that the choice of stabilizing agents should be made depending on the speciation of the contaminant or else an opposite impact (i.e., increase in contaminant mobility) might be triggered.

Utilization Of Fly Ash In Heavy Metal Removal From Acid Mine Drainage

Acid mine drainage (AMD) contains very toxic heavy metal with strong acidity. The high concentration of heavy metals in AMD have the potential as a major contamination sources that affect human life, aquatic and other natural resources. In this study, the removal of heavy metals was carried out by using low-cost industrial waste material which is fly ash. The adsorption capacity of fly ash was determined by two methods which are batch adsorption and tank remediation test. The effects of quantity of dosage, pH and heavy metal concentration were investigated. Fly ash consist of carbonate minerals (>50%) with high potential as adsorbent material to treat acid mine. The maximum adsorption rate for fly ash occurred at pH 5 for Pb, pH 7 for Zn and pH 3 for Cu. Adsorption capacity also increased with increasing dose. Fly ash as high alkaline material remediated and neutralized AMD solution from acidic phase (pH 2.11) to neutral phase (pH 7.09). Increasing pH value during treatment process will increase the capacity of the removal of heavy metals.

Improving consistency at testing cementitious materials in the Dynamic Surface Leaching Test on the basis of the European technical specification CEN/TS 16637–2 – Results of a round robin test

The environmental impact assessment of materials is usually based on laboratory tests, mostly in combination with models describing the longterm fate of the substances of interest in the targeted environmental compartment. Thus, laboratory tests are the fundamental link to achieve appropriate assessment conclusions which makes it essential to generate consistent results. This just as applies to the leaching of cementitious materials. In Europe, the leaching behavior of monolithic building materials is tested in the Dynamic Surface Leaching Test following the specification CEN/TS 16637–2. An interlaboratory comparison on European level regarding this technical specification showed relatively high intra- and interlaboratory variations for the tested materials (monolithic copper slag and cement stabilized coal fly ash). Therefore the German Committee for Structural Concrete (DAfStb) framed a guideline to specify additional testing conditions for cementitious materials. To assess the possible improvement by this guidelines measures, a round robin test with 11 participants from Germany and the Netherlands was conducted. This work aims to provide insight into the factors to be considered in the testing of alkaline materials, including sample preparation, and highlights crucial procedures and their manifestation in the results. All evaluated parameters showed improved results compared to the earlier round robin test. The relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) of the elements calcium, barium, antimony, chromium, molybdenum and vanadium, which are the parameters evaluated in both round robin tests, were RSDr = 4%, 4%, 2%, 5%, 5%, and 5% respectively (4% in average) for this work, in comparison to the European round robin test with an average RSDr of 29% (17%, 17%, 20%, 40%, 36%, and 42%). The RSDR improved from 41% (30%, 36%, 29%, 57%, 40%, and 56%) to 14% (12%, 8%, 6%, 28%, 15%, and 12%). CO2 ingress during testing and the inaccuracy of eluate analytics for concentrations close to the determination limits were identified as the main sources of error.

Effect of sulfate on CO2 binding efficiency of recycled alkaline materials

CO2 mineralization using alkaline waste materials and by-products is a promising technology to reduce CO2 emissions. This work investigates the impact of alkali sulfates on the carbonation process. Detailed investigations of the carbonation reaction show that the sulfates are important phases impacting the mineralization. Alkalis alone accelerate the kinetics and change the morphology of the precipitated phases. Sulfates additionally reduce the amount of CO2 mineralized since a part of calcium precipitates as calcium sulfate. The mutual interaction between alkalis and sulfate ions provides a tool to control the mineralization kinetics and especially the extent of carbonation by preventing calcium sulfate precipitation at surplus of alkalis. Furthermore, sulfate-containing materials, which so far have not been considered as suitable for CO2 mineralization (e.g. gypsum), can now be considered for CO2 sequestration. A modification of the Steinour formula, used for calculations of the carbonation potential, is proposed to account for the observed effects.

Digital soil assessment in support of a soil information system for monitoring salinization and sodification in agricultural areas

AbstractSalinization and sodification are types of degradation associated with the accumulation of salts and alkaline materials in the soil. They gradually advance unnoticed till severe degradation appears if not properly controlled. Relevant soil information is not routinely kept by many countries thus contributing to their advancement particularly in agricultural areas where their impacts have huge consequences on food security. We developed a 3‐step protocol to detect salinization and sodification advancement at different spatial scales and support soil information system development. The first step establishes an indicator database focusing on measured soil Electrical Conductivity (EC), pH, Exchangeable Sodium Percent (ESP), and a suit of environmental covariates. The second step outlines data harmonization strategies and classification of salinization and sodification problems. It also incorporates digital soil mapping for spatial information on salinization or sodification. The third step has time‐series modelling of salinization and sodification using mixed‐effects approach to improve hotspot detection in agricultural areas. The protocol was tested in Afghanistan, Sudan, and Lesotho using time‐series data between 2001 and 2018. It successfully identified salt and soda accumulation at different soil depths with more than 80% accuracy on holdout samples. In Sudan and Afghanistan, it identified topsoils as more prone to salinization than the subsoils and consequently depicted more salt accumulation in topsoils than subsoils in agricultural areas. In Lesotho, it identified emerging subsoil sodification. The protocol has potential for supporting the development of soil information on salinization and sodification which is currently lacking at many national and regional levels.

Biochar, compost, iron oxide, manure, and inorganic fertilizer affect bioavailability of arsenic and improve soil quality of an abandoned arsenic-contaminated gold mine spoil

Arsenic (As) contaminated mining spoils pose health threats to environmental resources and humans, and thus, mitigating this potential risk is worth investigating. Here, we studied the impacts of biochar, compost, iron oxide, manure, and inorganic fertilizer on the non-specifically (readily bioavailable)- and specifically- sorbed As and soil quality improvement of an abandoned mine spoil highly contaminated with As (total As = 1807 mg/kg). Compost, iron oxide, manure, and biochar were each applied at 0.5%, 2%, and 5% (w/w) to the contaminated soil; and NPK fertilizer at 0.1, 0.2, and 5.0 g/kg. The non-specifically (readily bioavailable)- and specifically- sorbed As were extracted sequentially and available P, total C and N, dissolved organic carbon, soil soluble anions, and exchangeable cations were extracted after 1- and 28-day incubation. Compost, manure, and biochar at 5% improved the total C and N and exchangeable K+, Mg2+ and Na+. However, manure, compost, and iron oxide at 5% reduced available P from 118.5 to 60.3, 12.6, and 7.1 mg/kg, respectively. As compared to the untreated soil, the addition of iron oxide doses reduced the readily bioavailable As by 93%; while compost, manure, inorganic fertilizers, and biochar increased it by 106–332%, 24–315%, 19–398%, and 28–47%, respectively, with a significantly higher impact for the 5% doses. Furthermore, compost reduced specifically-sorbed As content (14–37%), but the other amendments did not significantly affect it. The impacts of the amendments on the readily bioavailable As was stronger than on specifically-sorbed As; but these were not affected by the incubation period. Arsenic bioavailability in our soil increased with increasing the soil pH and the contents of Cl-, DOC, and exchangeable K+ and Na+. We conclude that iron-rich materials can be used to reduce As bioavailability and to mitigate the associated environmental and human health risk in such mining spoils. However, the carbon-, and P-rich and alkaline materials increased the bioavailability of As, which indicates that these amendments may increase the risk of As, but can be used to enhance phytoextraction efficiency of As in the gold mining spoil.