Diamant LLC, Dubna, Russia:

E. A. Razinkov, Senior Engineer, erazinkov@diamant-sk.ru
V. Yu. Aleksakhin, Leading Program Designer
Yu. N. Rogov, Head of Programming Office
M. G. Sapozhnikov, Research Manager, Professor, Doctor of Physical and Mathematical Sciences

The results of the pilot operation of the AGP-F facility in determination of mass fraction of phosphorus pentoxide in phosphorus ores are discussed. The facility operates by the tagged neutron method, irradiates ore with fast neutrons with an energy of 14 MeV and records the characteristic emission of gamma rays from inelastic neutron scattering reactions. The pilot operation of the AGP-F facility at Vostochny Mine of Apatit JSC well demonstrated the main features of the elemental analysis of apatite–nepheline ores using the tagged neutron method. This is primarily the absence of any sample preparation and the ability to determine the elemental composition of samples of large mass (3–5 kg) and size (up to 100 mm). Based on measurements of 75 ordinary samples with a particle size of -10 0 mm, the measurement accuracy was estimated. The absolute value of the standard deviation in the range of P₂O₅ contents of 2–25% is RMSabs = 1.17% P₂O₅ (RMS_rel = 8.3%) with a measurement time of 10 minutes. Measurements of the calibration collection of 69 samples with a size of -3 mm showed RMS_rel = 3.33% in the range of P₂O₅ of 1-40%. The minimal concentration of P₂O₅ was determined. It was 1.71%. Measurements of 58 samples with size of -100 mm made it possible to determine a transient response that relates the values of the AGP parameter for samples with size of -100 mm and with size of -3 mm. An important result was obtained on the simple linear dependence of this characteristic. It shows that due to the high penetrating power of fast neutrons with an energy of 14 MeV, a natural averaging of the elemental concentration over the entire sample material occurs and the value of the AGP parameter becomes the same for both the large-sized sample and small ones. This result is important to for the future use of TNM for a conveyor system. The tests have fully confirmed the consistency of the tagged neutron method for determining the elemental composition of phosphorus ores. The applicability of the tagged neutron method for determining mass concentrations of 25 chemical elements (Na, Mg, C, N, O, F, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Zr, Pb, Sn, Bi, Sb) is verified.
This article is devoted to the memory of Dr. Phys.-Math. V. M. Bystritsky who greatly contributed to the tagged neutron method development and the AGP-F facility engineering.
The authors express their deep gratitude to: S. A. Zhurba and Skolkovo Innovation Center for the sponsorship of the pilot facility manufacturing; V. B. Melnik, I. V. Salnikov, I. Yu. Rybin, A. A. Skryabin, E. V. Persiyanov, N. B. Domosevich and D. A. Mikhailov from Apatit’s Division in Kirov for the help in experimentation; E. A. Andreev, E. V. Zubarev, P. P. Reunov, A. B. Sadovsky and O. G. Tarasov from Diamant LLC for the participation in engineering and testing of AGP-F facility.

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