Decomposition Of Pyrite Research Articles

Effect of calcite on the thermal decomposition of pyrite: Thermodynamics, phase transformation, microstructure evolution and kinetics

Pyrite, a common iron mineral in refractory iron ores, emits SO2 during oxidative roasting, contributing to environmental pollution. This study investigated the effect of calcite on the thermal decomposition of pyrite, focusing on thermodynamics, phase transformation, microstructural evolution, and non-isothermal kinetics, with emphasis on SO2 formation inhibition. Results showed that pyrite decomposed first to pyrrhotite, then to magnetite and hematite, with SO2 as the primary gaseous product. Higher temperatures and lower oxygen concentrations favored S2 gas formation. Non-isothermal decomposition of pyrite occurred between 400–725°C, initiated at the particle surface, and significantly increased product porosity, resulting in butterfly-shaped hematite. The addition of calcite resulted in the reaction of SO2 with calcite to form anhydrite on the particle surface, inhibiting the release of SO2. Initially, the thermal decomposition of pyrite proceeded with a low apparent activation energy, making the reaction relatively easy. However, the presence of calcite significantly increased the apparent activation energy and inhibited the thermal decomposition reaction.

The release and migration mechanism of arsenic during pyrolysis process of Chinese coals

Special attention was drawn to the heavy metals contained in coal, due to it will cause harm to the environment during coal processing and utilization. The sequential chemical extraction of Shanxi coal (SX coal) and Wulanchabu coal (WLCB coal) was carried out to investigate the distribution of arsenic (As) in coals. Two raw coals were pyrolyzed at 300–900 °C in horizontal tubular furnace to investigate release behavior of As during pyrolysis process. The results showed that As in SX coal mainly existed in aluminosilicate-bound state (40.25%) and disulfide-bound state (32.51%), followed by carbonate-bound state and organic-bound state. The As in WLCB coal mainly existed in aluminosilicate-bound state (62.50%), followed by disulfide-bound state (19.10%). The As contents of water-soluble, ion-exchange and residue states in the two coals were less than others. The modes of occurrence of As had great influence on its volatilization behavior. As in organic part was easy to volatilize at low temperature. Sulfide-bound state would escape with the decomposition of pyrite. Because SX coal contained higher organic state and sulfide-bound state, the volatilization rate of As was higher than WLCB coal at any temperature, and the difference was more obvious at low temperature. In addition, FactSage simulation value was basically consistent with the experimental value.

Novel targeted extraction of lithium: An environment-friendly controlled sulfidation roasting technology and mechanism for recovering spent lithium-ion batteries

Due to the needs of protecting the environment and recycling resources, the extraction of lithium from spent lithium-ion batteries has become increasingly important. Different from the traditional roasting process, a novel approach for the selective recovery of lithium from spent LiCoO2 (SLCO) through low-temperature sulfidation roasting was proposed in the present work. The thermodynamics of the sulfidation roasting was investigated and phase transformation was detected. The results showed that the S2 gas generated from the decomposition of pyrite converted LiCoO2 into Li2SO4 and cobalt sulfides. Under optimal experimental conditions, lithium can be selectively leached with a yield of more than 99% through water immersion treatment, resulting in around 20% improvement in the overall recovery rate of the metal compared to current industrial practices. The thermochemical process did not produce toxic SOx gases, whereas the selective leaching process for lithium did not require additional reagents, resulting in good environmental and economic benefits.

Thermodynamic Behavior of Pyrite and Arsenopyrite in Preoxidation for Chlorination Leaching of Refractory Gold Concentrate

Recently, preoxidation is an effective pretreatment method of refractory gold ore, which has been widely used due to the high desulfurization, arsenic removal, low environmental pollution, and rapid reaction rate. In this paper, we describe the thermodynamic considerations of preoxidation of pyrite and arsenopyrite, the main minerals of the refractory gold ore, and the effect of the pressure oxidation, one of the preoxidation processes on the chlorination leaching. The thermodynamic results indicated that arsenopyrite under acidic conditions is easier to oxidize compared to pyrite and the oxidation decomposition of pyrite and arsenopyrite-type gold ore can be considered mainly for pyrite. The experiment has shown that the arsenic removal rate was higher than the desulfurization rate; it is confirmed that the thermodynamic conclusion of the oxidation of pyrite and arsenopyrite was correct. Comparing the XRD, SEM, and EDX analyses of gold concentrate and pressurized oxidation residue, it can be seen that the surface of pressurized oxidation residue is a fine porous structure and the dense and durable structure of sulfide ore is mainly destroyed.

Operando exploration of tribochemical decomposition in synthetic FeS2 thin film and mineral iron pyrite

The tribochemical decomposition of iron pyrite at room temperature involves rich solid-state reactions of FeS2 with impurities such as hydrogen, oxygen and carbon and is controlled by the concentrations of precursors.

Re-Os Systematics in the Layered Rocks and Cu-Ni-PGE Sulfide Ores from the Dovyren Intrusive Complex in Southern Siberia, Russia: Implications for the Original Mantle Source and the Effects of Two-Stage Crustal Contamination

The Dovyren Intrusive Complex (Northern Baikal region, 728 ± 3 Ma) includes the dunite–troctolite–gabbronorite Yoko–Dovyren massif (YDM) associated with a sequence of underlying mafic-to-ultramafic sills, locally demonstrating interbedding relations with the most primitive rocks of the pluton. These sills and apophyses contain sulfide mineralization ranging from globular to net-textured and massive ores. Major types of the YDM cumulates and sulfide mineralization were examined for their PGE contents and Re-Os isotopic systematics. The ten analyzed samples included chilled and basal rocks, poorly mineralized troctolite, PGE-rich anorthosite, as well as three samples from a thick ore-bearing apophysis DV10 connected with the YDM. These samples yielded a Re-Os isochron with an age of 759 ± 36 Ma and an initial 187Os/188Os of 0.1309 ± 0.0026 (MSWD = 110), which is in consistent with the previously reported U–Pb zircon age. It is shown that being recalculated to γOs(t) at t = 728 Ma, these isotopic compositions demonstrate three clusters regarding the relationship between γOs(t) and 187Re/188Os: (i) the chilled gabbronorite (YDM) and subcontact olivine gabbronorite (DV10) yielded the most radiogenic values of γOs(t) 10.5 and 10.0 among basal ultramafics, (ii) plagiodunite, troctolite, and sulfide ores showed lower radiogenic compositions, with γOs(t) ranging from 7.3 to 8.7, (iii) olivine gabbronorite, plagioperidotite, and one sample of PGE-rich anorthosite yield very primitive γOs(t) in the range 4.5 to 5.6 (on average 5.2 ± 0.6). The lowest values of γOs(t) for the least fractionated rocks of the YDM suggest a primitive mantle source, formed from a partly contaminated Neoarchean protolith, which is considered to be anomalous in Upper Riphean due to very low εNd(t) of −16 for the most primitive Dovyren magma (Fo88-parent). The highest values of γOs(t) and relative enrichment in the 34S isotope in the chilled gabbronorite (YDM) and subcontact olivine gabbronorite (DV10) evidence that their primitive to evolved magmatic precursors could be affected by a metamorphic fluid enriched in radiogenic 187Os, originating in the exocontact halo due to the thermal decomposition of pyrite from the dehydrated country rocks. This is consistent with the second-stage contamination of the Dovyren magma by the hosting crustal rocks (probably of 10 wt% shists), generating more evolved Fo86-parent magma with higher εNd(t) of −14.

Sulfur Transformation during Coal Pyrolysis with Char Heat Carrier

AbstractTo investigate sulfur transformation during coal pyrolysis with char heat carrier (CHC), the effects of temperature, CHC/coal, and CHC production temperature were explored in a fluidized bed. The yield rates of sulfur in H2S () and YCOS elevated with temperature. and Ychar‐S decreased, and temperature showed no significant effect on Ytar‐S. CHC inhibited sulfur transformation to the gas phase. More H2S and COS were fixed in mixed‐char in form of CaS by CHC, resulting in the increase of Ychar‐S. CHC was favorable for CH3SH decomposition. The inhibitory effect was enhanced with increasing CHC/coal. Higher production temperature inhibited the sulfur fixation capacity of CHC. CHC enhanced the decomposition of pyrite, organic sulfur, sulfate, and the yield of sulfide in mixed‐char.

Effect of redox agents on the reaction behavior of pyrite in sodium aluminate solution at elevated temperatures

As the main sulfide mineral in diasporic bauxite, pyrite readily reacts with sodium aluminate solution in Bayer digestion at elevated temperatures, adversely affecting the utilization of high-sulfur bauxite for alumina production by the Bayer process. For better understanding of the reaction mechanism during Bayer digestion, this paper focuses on the impacts of oxidant and reductant on the reaction extents of pyrite at elevated temperatures. The extents of reaction between pyrite and sodium aluminate solution are 57.9, 38.3 and 99.0 % at 260 °C for 40 min with no, oxidant and reductant addition, respectively. In the presence of oxidant, a dense layer formed on the surface of unreacted pyrite retarding the reaction with sodium aluminate solution, which follows the Kröger and Ziegler diffusion control model at 240–260 °C. However, the presence of reductant favors the decomposition of pyrite due to the formation of hematite and then transformation to magnetite, and the development of “chemical etching channel”. Finally, the above results were experimentally verified by digesting high-sulfur diasporic bauxite at 260 °C for 60 min, in which the inhibition of pyrite reaction with oxidant addition is affected by the organic content of the bauxite. These results may facilitate the development of a technique for directly treating the high-sulfur diasporic bauxite for alumina production with the Bayer process bypassing desulfurization pretreatment.

Correction: Thermal decomposition and oxidation of pyrite with different morphologies in the coal gangue of North China

Correction: Thermal decomposition and oxidation of pyrite with different morphologies in the coal gangue of North China

Thermal decomposition and oxidation of pyrite with different morphologies in the coal gangue of North China

Thermal decomposition and oxidation of pyrite with different morphologies in the coal gangue of North China

Thermal Behavior of Estonian Graptolite–Argillite from Different Deposits

Graptolite–argillites (black shales) are studied as potential source of different metals. In the processing technologies of graptolite–argillites, a preceding thermal treatment is often applied. In this study, the thermal behavior of Estonian graptolite–argillite (GA) samples from Toolse, Sillamäe and Pakri areas were studied using a Setaram Labsys Evo 1600 thermoanalyzer coupled with the Pfeiffer OmniStar Mass Spectrometer. The products of thermal treatment were studied by XRD, FTIR, and SEM analytical methods. The experiments were carried out under non-isothermal conditions of up to 1200 °C at different heating rates in the atmosphere containing 79% Ar and 21% O2. The differential isoconversional Friedman method was applied for calculating the kinetic parameters. All studied GA samples are characterized with high content of orthoclase (between 38.0 and 57.3%) and quartz (between 23.8 and 35.5%), and with lower content of muscovite, jarosite, pyrite, etc. The content of organic carbon in GA samples studied varied between 7.3 and 14.2%. The results indicated that, up to 200 °C, the emission of hygroscopic and physically bound water takes place. Between 200 °C and 500–550 °C, this is followed by thermo-oxidative decomposition of organic matter. The first step of thermo-oxidation of pyrite with the emission of water, carbon and sulphur dioxide, nitrogen oxides, and different hydrocarbon fragments indicated the complicated composition of organic matter. At higher temperatures, between 550 °C and 900 °C, the transformations continued by dehydroxylation processes in clay minerals, and the decomposition of jarosite and carbonates took place. At temperatures above 1000–1050 °C, a slow increase in the emission of sulphur dioxide followed, indicating the beginning of the second step of thermo-oxidative decomposition of pyrite, which was not completed for temperatures of up to 1000 °C. Kinetic calculations prove the complicated mechanism of thermal decomposition of GA samples: for Pakri GA samples, it occurs in two steps, and for Silllamäe and Toolse GA samples, it occurs in three steps. Preliminary tests for the estimation of the influence of pre-roasting of GA samples on the solubility of different elements contained in GA at the following leaching in sulphuric acid is based on Toolse GA sample.

Pyrite roasting in modified fluidized bed: Experimental and modeling analysis

In this study, a modified fluidized bed reactor was used to roast pyrite concentrate (PC). To analyze the pyrite conversion and fluid flow in the bed, a 2D model incorporating the Euler–Euler method and the conservation equation of chemical species was employed. In addition, the reactant and product samples were characterized through X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size distribution, and thermogravimetric analyses (TGA). The kinetic parameters of the pyrite decomposition were also determined. The isoconversional method was used to determine the activation energy, pre-exponential factor of the specific reaction-rate equation, and reaction mechanism from thermogravimetry results. This rate law was then applied in the model to account for the depletion of pyrite in the modified fluidized bed. The main crystallographic phase in the formed product was hematite. XRF and TGA result indicate that the PC had high purity and roasting occurred at a conversion of 80 %. The pyrite decomposition kinetics showed activation energy varies from 33.2 to 281.4 kJ∙mol−1 depending on the stage. The kinetic analysis of roasting and its implementation in the model demonstrated that the simulation achieved 72 % PC conversion into the products. These results validate the experimental conversion, illustrating the compatibility of the model with the experimental data. Specifically, the coupling of the rate law from TGA with the dispersed-phase velocity vector encourages to new research possibilities in this field of chemical engineering.

Bleached-spot formation in Fe-oxide-rich rock by inorganic process

In sedimentary rocks rich in Fe-oxide, such as red beds, white bleached spots that are free of Fe-oxide minerals are often observed. The spot formation has been explained by localized reduction reactions in relation to organic substances, such as fluids including hydrocarbon and organic debris as a precursor, and the recent major prevalent approach is the microbial activity in sediments. However, the evidence for microbial activities within the spots is rarely found, and it remains debatable whether the entire spots are of microorganism origin. We discovered bleached spots in zebra rock, which is the sedimentary rock from northern Australia with rhythmic Fe-oxide bands, and explained that the spots were formed by pH changes induced by the decomposition of primary pyrite. Our comprehensive petrological studies further demonstrate that the spots developed during the infiltration of the acidic fluid in relation to the Fe-oxide band formation, and the primary pyrite as a precursor is currently preserved as a pseudomorph composed of dickite and aggregation of hematite and goethite. This study demonstrates that the bleached spots in zebra rock were formed by inorganic chemical reactions, indicating that the proposal in other studies that spots of this kind can be used as a biomarker to find life on Mars is not always available.

Unraveling the dissociation mechanism of gold in carbonaceous gold ore during vacuum roasting pretreatment: Effect of pyrite

Carbonaceous refractory gold ore has been an important gold ore resource for the sustainable development of the gold industry. Solving the harmful effects of mineral-locking is the first step to increase the gold leaching rate. This study employed vacuum roasting technology in the pretreatment of carbonaceous gold ore. The dissociation efficiency and mechanism of gold in carbonaceous gold ore was investigated using a Mineral Liberation Analyser, thermogravimetric analysis, scanning electron microscopy, and X-ray diffraction analysis. The results showed that the effect of gold-locking could be effectively solved through the thermal decomposition of pyrite during vacuum roasting pretreatment. After vacuum roasting, the content of exposed and semi-exposed gold increased from 43.81% to 78.34%, and 72.37% of the gold locked by pyrite was dissociated. Pyrite was continuously desulfurized and converted into low-sulfur pyrrhotite during vacuum roasting, and desulfurization at 400–700 °C was the cause of mass loss and phase transformation of pyrite. The phase transformation of pyrite followed the change pyrite → monoclinic and hexagonal pyrrhotite → hexagonal pyrrhotite → troilite. At 600–700 °C, rapid desulfurization produced a well-developed pore structure of the pyrite particles, which loosened the connection between gold and pyrite. Above 700 °C, the aggregation of pyrrhotite particles by slow desulfurization improved separation of gold and pyrrhotite. Gold locked by pyrite in the carbonaceous gold ore was dissociated effectively under the combined action of the two stages. The high content of exposed and semi-exposed gold provided necessary conditions for the improvement of gold leaching rate in the later leaching process.

Raman Spectroscopic Studies of Pyrite at High Pressure and High Temperature

Variations in the Raman spectra of pyrite were studied from 113 to 853 K at room pressure with a Linkam heating and freezing stage, and for 297–513 K and pressures up to 1.9 GPa with a hydrothermal diamond anvil cell. All observed frequencies decreased continuously with an increase in temperatures up to 653 K at ambient pressure. Hematite began to form at 653 K, all pyrite had transformed to hematite (H) at 688 K, and the hematite melted at 853 K. An increase in temperature at every initial pressure (group 1: 0.5 GPa, group 2: 1.1 GPa, group 3: 1.7 GPa, group 4: 1.9 GPa), showed no evidence for chemical reaction or pyrite decomposition. Two or three Raman modes were observed because of crystal orientation or temperature-induced fluorescence effects. The pressure groups showed a decreasing trend of frequency with gradual heating. The interaction of pressure and temperature led to a gradual decrease in Ag and Eg mode at a lower pressure (0.5 GPa and 1.1 GPa) than other pressure groups. Pressure and temperature effects are evident for groups 1 and 2; however, for groups 3 and 4, the temperature shows a larger effect than pressure and leads to a sharp decrease in Ag and Eg modes.

Bulk synthesis of stoichiometric/meteoritic troilite (FeS) by high‐temperature pyrite decomposition and pyrrhotite melting

AbstractStoichiometric troilite (FeS) is a common phase in differentiated and undifferentiated meteorites. It is the endmember of the iron sulfide system. Troilite is important for investigating shock metamorphism in meteorites and studying spectral properties and space weathering of planetary bodies. Thus, obtaining coarse‐grained meteoritic troilite in quantities is beneficial for these fields. The previous synthesis of troilite was achieved by pyrite or pyrrhotite heating treatments or chemical syntheses. However, most of these works lacked a visual characterization of the step by step process and the final product, the production of large quantities, and they were not readily advertised to planetary scientists or the meteoritical research community. Here, we illustrate a two‐step heat treatment of pyrite to synthesize troilite. Pyrite powder was decomposed to pyrrhotite at 1023–1073 K for 4–6 h in Ar; the run product was then retrieved and reheated for 1 h at 1498–1598 K in N2 (gas). The minerals were analyzed with a scanning electron microscope, X‐ray diffraction (XRD) at room temperature, and in situ high‐temperature XRD. The primary observation of synthesis from pyrrhotite to troilite is the shift of a major diffraction peak from ~43.2°2θ to ~43.8°2θ. Troilite spectra matched an XRD analysis of natural meteoritic troilite. Slight contamination of Fe was observed during cooling to troilite, and alumina crucibles locally reacted with troilite. The habitus and size of troilite crystals allowed us to store it as large grains rather than powder; 27 g of pyrite yielded 17 g of stochiometric troilite.

Volatilization characteristics and relationship of arsenic and sulfur during coal pyrolysis

Similarities concerning the occurrence of arsenic and sulfur in coal are the reasons for studying the relationship between the volatilization of arsenic and sulfur during the pyrolysis process. For this purpose, three coals with different arsenic and sulfur contents were selected. Combined application of electron probe microanalysis (EPMA) and sequential chemical extraction determined the relationship between the speciation of arsenic and sulfur (especially pyrite) in coal. Effects of temperature and speciation on the volatilization of arsenic and sulfur were discussed. Results show that arsenic in all coals is significantly enriched in the distribution area of pyrite. The volatilization ratio of sulfur and arsenic increases with temperature, and their volatilization mainly occurs at 300–600 °C. Before 500 °C, aliphatic sulfur and organic arsenous are the main contributors to the volatilization of sulfur and arsenic, respectively. At 500–600 °C, the volatile sulfur and arsenic mainly come from the decomposition of pyrite. A characteristic peak is observed for the volatilization rate of arsenic and sulfur, and it almost coincided with the weight loss peak of coal. Moreover, the simultaneous volatilization behavior of arsenic and sulfur is observed in Gansu (GS) coal at 400 °C due to the devolatilization of coal and in Chongqing (CQ) coal at 550 °C due to the decomposition of pyrite. Sulfate in coal has a negative effect on the volatilization of arsenic. The possible reaction paths were predicted by the thermodynamic analysis of FactSage 7.3 software. Fe2O3 and CaS could adsorb arsenic to form stable arsenate (FeAsO4 and Ca3(AsO4)2) during the pyrolysis process.

Effects of atmosphere on mineral transformation of Zhundong coal during gasification in CO2/H2O conditions

Coal gasification has been regarded as a promising method for the thermochemical utilization of Zhundong (ZD) coals. However, ZD coals are characterized by the high content of alkali metal, which may cause a series of running problems such as ash accumulation, slag blocking and fouling on heating surface of the gasifier and waste heat boiler. To improve the efficiency of fuels utilization, the evolution behavior of minerals of ZD coals – Hongshaquan (HSQ) coal and Jiangjunmiao (JJM) coal was investigated by experiment and FactSage calculation in this work. The results gained by low temperature ashing method show that the minerals of both HSQ coal and JJM coal are basically similar mainly including quartz, kaolinite, calcite, halite and of pyrite. It was found that the minerals transformation of coal samples is greatly influenced by gasification atmosphere (CO2/H2O). For HSQ coal, the minerals of slag are mainly composed of quartz, nepheline, gehlenite and periclase under pure H2O or pure CO2 atmospheres, while the minerals of slag are mainly lime and periclase under the mixing CO2/H2O (CO2: H2O = 1:1) atmosphere. For JJM coal, the minerals of slag under the pure H2O atmosphere are obvious different from that under the pure CO2 atmosphere, and mainly include gehlenite, lime, magnesia, and nepheline in pure H2O atmosphere, and the pleonaste and merwinite minerals are detected under pure CO2 and CO2/H2O (CO2: H2O = 1:1) mixing atmosphere. Furthermore, the FTIR results for the two coal samples demonstrate that the more silicate minerals exist in coal slag, which might be caused by the factor that H2O promotes the melting and polycondensation of SiO2 and Al2O3 to increase the quantity of silicate. In addition, according to the calculation results of FactSage, iron is formed during the evolution of iron-containing minerals with water vapor in atmosphere which may be due to the promotion effect of water on the decomposition of pyrite in coal slag. Moreover, water vapor can promote the migration of the alkali metal sodium in the coal slag to the gas phase, reducing the sodium content in the slag, and thus results in a higher viscosity of the molten slag under the water vapor atmosphere than under the pure CO2 atmosphere. The order of slag viscosity is: η0(H2O) > η0(CO2/H2O) > η0(CO2). This work provides a theoretical information for the effect of CO2/H2O gasification conditions on the mineral’s evolution behavior of ZD coal and offers a guidance for the operation of gasifier.

Application of FTA Analysis for Calculation of the Probability of the Failure of the Pressure Leaching Process

European Union legislation requires organizations to assess their processes in the context of risk management. The main task of risk management is to manage all risks that can significantly affect the outcome of processes. The article is focused on risk evaluation in pressure leaching at elevated temperature using the method Fault Tree Analysis (FTA). The effectivity of pyrite and arsenic pyrite decomposition by oxidative pressure leaching is influenced by the duration of the process, by the temperature, concentration of the leaching solution and by a density of the slurry. It was found that, under equitable conditions, the arsenic pyrite decomposes more intensely than pyrite. Under laboratory conditions, leaching is performed in an autoclave. Due to the aggressive environment, increased pressure and temperature, process failure is possible. Its probability was calculated by FTA. It has been found that the probability of the top event in the examined process was disproportionately high (0.057) and represents an invitation to take corrective actions. The Monte Carlo method was used for the simulation of the effect the probability of basic events on the probability of the top event—the failure of the leaching process.

Mechanisms of sulfur and nitrogen transformation during Longkou oil shale pyrolysis

Recently, shrinking reserves of crude oil have led to increased interest in the utilisation of various unconventional resources. Oil shale is one of these promising alternatives to crude oil. However, the transformation of S/N that takes place during the oil shale pyrolysis cannot be ignored since they contribute to the release of harmful gases and production of poor-quality shale oil. In order to study the mechanism of S/N migration during pyrolysis, S/N species in the pyrolysates produced from the Longkou oil shale were qualitatively and quantitatively examined over a temperature range of 340–520 °C. The results revealed that a majority of the S retained in char during pyrolysis was primarily present as aromatic S, sulfone and sulfate. Aromatic S in the char decreased when at a temperature below 460 °C and increased when in the 460–520 °C range; sulfone in the char increased during the initial stage and decreased in the last stage; and sulfate in the char showed a fluctuating pattern. At lower temperatures (≤400 °C), more gases (H2S, CH3SH and COS) were produced via the decomposition of pyrite and cleavage reactions of aliphatic and aromatic S, when compared with the liquid S species. At higher temperatures (≥400 °C), an increasing amount of S migrated to shale oil, with the most abundant form being thiophenes. Concerning the transformation of N during pyrolysis, abundant N was present in the char, with a predominant occurrence of pyrrolic N. At temperatures below 340 °C, the pyrrolic N in the char was seen to change slightly, while when the temperature increased from 340 °C to 520 °C, it decreased significantly. By raising the temperature in the tested range, the N compounds were promoted to migrate into both shale oil and gas, and the production of liquid N species was recorded as higher than that of gaseous N (NH3 and HCN), especially after surpassing 400 °C. More non-basic or weak basic N species, such as indoles, carbazoles and aliphatic nitriles, were present in shale oil than basic N species (anilines and quinolines). These findings suggest that regulating and controlling S/N transformation during oil shale pyrolysis would improve the quality of shale oil. In addition, it would provide basic data to be used in the subsequent processing for the efficient and clean utilisation of oil shale.