A study of thermal decomposition of antigorite from dunite and lizardite from peridotite

Zulumyan, N. H.; Isahakyan, Anna; Beglaryan, H. A.; Melikyan, Stella

doi:10.1007/s10973-017-6705-6

Cited by 21 publications

(5 citation statements)

References 27 publications

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“…The study of serpentine thermolysis supervised by N.O. Zulumyan has shown that the efficiency of serpentine amorphization is primarily associated with the conditions of their formation in the Earth's crust [26]. The degree of silica extraction upon acid treatment in the current study was done in accordance with the method proposed by N.O.…”

Section: Characteristics Of Heat-treated Serpentinesmentioning

confidence: 91%

Magnesium Silicate Binding Materials Formed from Heat-Treated Serpentine-Group Minerals and Aqueous Solutions: Structural Features, Acid-Neutralizing Capacity, and Strength Properties

et al. 2022

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The influence of structural features of three serpentine-group minerals (antigorite, chrysotile, and lizardite) on the hydration of heat-treated materials and the formation of magnesium silicate binder has been studied. Initial serpentine samples have been fired in the interval 550–800 °C with a step of 50 °C; acid neutralization capacity (ANC) values have been determined for all samples. Antigorite samples (SAP) have exhibited a maximum reactivity at a temperature of 700 °C (ANC 7.7 meq/g). We have established that the acid-neutralizing capacity of chrysotile and lizardite samples in the temperature range of 650–700 °C differ slightly; the capacity varied in the interval of 19.6–19.7 meq/g and 19.6–19.7 meq/g, respectively. The samples obtained at optimal temperatures (antigorite—700 °C, lizardite, and chrysotile—650 °C) have been studied. Heat-treated serpentines have interacted with water vapor for a year; serpentine hydration has been investigated. The strength characteristics of the resulting binder agents were studied after 7, 28, 180, and 360 days. Upon hardening within 7 days, the strengths of the SAP and SCH samples have been almost the same (2.2 MPa), whereas this indicator for the SLH and SLK samples has been significantly lower (0.5 MPa). After hardening for over a year, the chrysotile sample SCH had the highest strength (about 8 MPa), whereas the strength of antigorite SAP was 3 MPa. The samples of initial, heat-treated, and hydrated heat-treated serpentines have been studied using XRD, differential scanning calorimetry, and surface texture analysis. The serpentine structure is crucial in destroying the mineral crystal lattice during heat treatment. In contrast to heat-treated chrysotile and lizardite, antigorite did not adsorb water. Structural features of chrysotile provided the highest compressive strength of the binding agent compared with antigorite and lizardite. The acid-neutralizing ability of lizardite was noticeably higher than antigorite, whereas its compressive strength was lower due to the layered mineral structure and impurities. We have established that the minerals’ structural features are crucial for the hydration of heat-treated serpentines; the structure determines material utilization in various environmental technologies.

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Section: Characteristics Of Heat-treated Serpentinesmentioning

confidence: 91%

Magnesium Silicate Binding Materials Formed from Heat-Treated Serpentine-Group Minerals and Aqueous Solutions: Structural Features, Acid-Neutralizing Capacity, and Strength Properties

et al. 2022

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“…In addition to the strengthening effect of the mineral particles, the complex physical and chemical reactions at the friction interface are the main reasons for the significant improvement in the tribological properties of PTFE matrix composites filled with antigorite and/or wollastonite, according to the worn surface analysis results in the present work. Antigorite minerals are composed of Mg-O octahedral layers and Si-O tetrahedral layers in a 1:1 ratio, and their crystal structures contain many active atomic groups and unsaturated bonds, such as O-Si-O, Si-O-Si, O-H-O, OH-Mg-OH/O, and -OH [30,31]. According to previous studies on phyllosilicates as lubricant additives, the crystal structure of antigorite is partially destroyed during friction.…”

Section: Tribological Mechanismmentioning

confidence: 99%

Preparation and Tribological Behaviors of Antigorite and Wollastonite Mineral Dual-Phase-Reinforced Polytetrafluoroethylene Matrix Composites

Wang,

Yu,

Yin

et al. 2024

Lubricants

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Research on polymer matrix composites with excellent tribological properties has received increasing attention in recent years. In this study, antigorite and wollastonite mineral dual-phase-reinforced polytetrafluoroethylene (PTFE) matrix composites were prepared by filling PTFE with mineral powders using ball-milling, cold-pressing, and pressureless sintering methods. The phase structure, microstructure, chemical composition, Shore hardness, and tribological behavior of the composites rubbed against steel balls under dry friction conditions were investigated. The results show that the composites have a dense structure and uniform distribution of mineral phases, with a Shore hardness of 62–68.8, an increase of 18.7–23.7% compared to pure PTFE. Compared with the addition of mono antigorite or wollastonite, the composites prepared by simultaneously filling the two minerals exhibited excellent tribological properties. The average friction coefficient and wear volume of the (10Atg + 20Wl)/PTFE composites were reduced by 44.2% and 71.4%, respectively, compared to those of pure PTFE. A dense and continuous tribofilm composed mainly of SiO2, MgSiO3, Mg2SiO4, MgO, CaO, CaMg(SiO3)2, and CaF2 was formed on the worn surfaces of both the dual-phase-reinforced PTFE matrix composites and counterpart steel balls during the friction process. The reduction in friction and wear is attributed to the reinforcement effect of the minerals on the PTFE matrix as well as the complex physical and chemical reactions at the friction interface stimulated by the synergistic effects between the two minerals. The addition of wollastonite reduced the phase transition temperature of antigorite, promoting more tribochemical reaction products with good abrasion resistance and friction-reducing properties, which contributed to the excellent tribological behavior of the composites.

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“…There exists a considerable body of research on the behavior of sulfides, silicates, and concentrates when heated both in air and in other environments [16][17][18][19][20][21][22][23]. In this case, the process is accompanied by the interaction of minerals with ammonium sulfate.…”

Section: Tg-dsc Study Of a Concentrate Mixture With Ammonium Sulfatementioning

confidence: 99%

A Study of the Feasibility of Using Ammonium Sulfate in Copper—Nickel Ore Processing

Goryachev

Chernousenko

Potapov

et al. 2021

Metals

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The possibility of applying a combined concentration and metallurgical method for processing low-grade and refractory copper–nickel ores was considered. The resulting rougher and scavenger flotation concentrate contained 2.07% nickel and 0.881% copper at a recovery of 85.44% and 89.91%, respectively. The concentrate was then roasted with ammonium sulfate, followed by aqueous leaching of clinker to dissolve nickel and copper. The roasting temperature, the ratio of concentrate to (NH4)2SO4 in the mixture, and the temperature were varied. Based on the study findings, the following process conditions were found to be optimal: roasting temperature 400 °С, rougher concentrate to ammonium sulfate ratio 1:7, and grinding size −40 μm. A roasting temperature of 400 °C is significantly lower than the temperature applied in conventional pyrometallurgical processes. The possibility of collecting off-gases allows the reagent to be regenerated and makes the process even more cost-effective. End-to-end recovery into pregnant solution was 81.42% for nickel and 82.81% for copper. The resulting solutions can be processed by known hydrometallurgical methods.

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A study of thermal decomposition of antigorite from dunite and lizardite from peridotite

Cited by 21 publications

References 27 publications

Magnesium Silicate Binding Materials Formed from Heat-Treated Serpentine-Group Minerals and Aqueous Solutions: Structural Features, Acid-Neutralizing Capacity, and Strength Properties

Magnesium Silicate Binding Materials Formed from Heat-Treated Serpentine-Group Minerals and Aqueous Solutions: Structural Features, Acid-Neutralizing Capacity, and Strength Properties

Preparation and Tribological Behaviors of Antigorite and Wollastonite Mineral Dual-Phase-Reinforced Polytetrafluoroethylene Matrix Composites

A Study of the Feasibility of Using Ammonium Sulfate in Copper—Nickel Ore Processing

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