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Separation of molybdenite from chalcopyrite, using graphene oxide as a novel depressant

Namiranian Afshin, Noaparast Mohammad, Tonkaboni Sied Ziaedin Shafaei

Archives of Mining Sciences

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2023

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Vol. 68, no. 1

71--86

EN

In this research, graphene oxide was introduced as an efficient flotation reagent for the selective separation of molybdenite from chalcopyrite. The performance of graphene oxide and its adsorption mechanism on chalcopyrite were investigated by flotation tests, FTIR spectra, and XPS measurements. First, graphene oxide was synthesised, and then its performance was evaluated by SEM, XRD, and EDX. Flotation tests were carried out in a hallimond flotation cell with a volume of 300 ml. Optimum flotation values were achieved at pH = 9 by adding 250 g/t of PAX (Potassium Amyl Xanthate) as a collector and 50 g/t of A65 (Poly Propylene Glycol) as a frother. The results showed high recovery, around 80% for molybdenite, while chalcopyrite was depressed in high amounts by employing 11 kg/t of graphene oxide as a depressant. Compared to common chalcopyrite depressants such as NaHS, Na2S, and C2H3NaO2S, graphene oxide had a higher potency in depressing, which can be applied as a green-depressant in the separation of molybdenite from chalcopyrite by the flotation process. Also, the validity of the depressing effect on chalcopyrite was verified by XPS and FTIR spectra.

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The effect of high voltage electrical pulses on iron ore comminution to improve desulfurization flotation recovery

Soltanmohammadi Vahid, Noaparast Mohammad, Aslani Soheila

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 150264

EN

In this research, the effect of employing high voltage electrical pulse (HVEP) on crushing to improve the recovery of iron ore desulfurization was investigated compared to mechanical crushing. To determine the effect of mechanical and electrical crushing, jaw crusher, cone crusher, and high voltage electrical pulse crusher (50Kv) were applied. The results indicated that coarser particles with fewer slimes are produced in the initial crushing stage using electric pulses. Selective separation mechanism from the boundary of the particles based on different dielectric constants, was the main difference between the HVEP method and mechanical crushing. In the flotation process of sulfide minerals crushed by an electric pulse crusher, recovery of the sample was 10.6% higher, and the grade of sulfur in flotation residue of iron ore concentrate was approximately 58% lower than the sample which was undergone through the initial mechanical crushing stage. The obtained results evidenced 37.5% increase in flotation kinetics constant while electric pulse crushing is preferred to mechanical crushing. For mineralogical studies, microparticles (-38 microns) were studied in the pulp phase of the sample, and the results proved that in the electric pulse crushing of the microparticles, they are dispersed, and there is a distance between them, while in the mechanical approach they are formed in the shape of agglomerated particles. This phenomenon leads to better preparation and further possible contact of pyrite particles with air bubbles, which increases flotation kinetics and the recovery of sulfur merely when electric pulse crushing was employed.

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Modelling of limestone calcination for optimisation of prallel flow regenerative shaft kiln (PFR), case study: Iran Alumina Plant

Mirzaei Hosseinali, Noaparast Mohammad, Abdollahi Hadi

Archives of Mining Sciences

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2022

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Vol. 67, no. 2

209--222

EN

To produce the lime required for the Bayer process, two parallel flow regenerative shaft kilns (PFR) were used in the Iran Alumina plant located in Jajarm, North Khorasan Province, Iran. In this study, the calcination conditions of limestone were modelled in a laboratory furnace by considering three factors of limestone size, temperature and calcination time using the Box-Behnken method. The calcination model of limestone was obtained using a quadratic equation. Due to the importance of limestone dust in the performance of industrial kilns, conditions of calcification and its reactivity with water were examined at three temperature ranges of 800, 1000, and 1200°C, by two methods of titration and standard ASTM C110. The results indicated a decrease in reactivity of lime relative to the increased temperature of calcination and the lack of forming the burnt lime particles that stick together (blocking). Finally, the ratio of input limestone (kg) to fuel (m3) was reduced from 16.4 to 15.3 to increase the average temperature of the burning zone to 1000°C. Also, excess air was reduced from 40 to 20%. In this condition, the lime quality was increased by about 6% in the kilns.