Abstract
Purpose. Theoretical and experimental studies of chemical and mineral composition and the structure peculiarities of phosphorites from Ukrainian deposits to define the degree of their suitability for other industries. Methods. The ore chemical composition was determined by conventional (wet) analysis using standard certified chemical reagents. The mineral composition was studied on the scanning electron microscope equipped with the attachment for the energy-dispersive electron microprobe analysis (EMPA) with the software for calculating the chemical composition of the studied sample microvolume. The petrographic analysis was carried out by the traditional methods of microscopic section preparation with subsequent identification and description of the minerals. The microscopic study of the original ore samples aimed at their mineral composition determination was conducted on the Nu optical microscope (Germany) both in transmitted and reflected light. The thin and polished sections prepared using the standard technology were used as samples. In the laboratory environment, the phosphorites were subjected to magnetic dressing in magnetic fields with different intensity. The experiments in the weak field were modelled with the help of the magnetic analyzer while the experiments in the strong magnetic field were modelled on the rotor separator. The flotation dressing method was studied on the laboratory mechanical flotation machine. Findings. It was found that phosphate nodules are rounded mineral formations of irregular shape; they consist of sand bound with the yellow-brown phosphate cement. Ore useful substance is a phosphorus-bearing mineral that by the element chemical composition corresponds to fluorocarbon-hydroxyl-apatite with the dominant content of Ca (45.23%), P (15.67%), and B (27.87%). The results of the integrated petrographic study of the phosphorite samples from the ore body of “Peremoha” area are presented. Originality.The study has revealed that phosphorus-containing substance in the phosphorite samples is the mass that cements barren minerals (mainly quartz, glauconite, calcite and plagioclase). Practical implications. According to the phosphate content level, the phosphorites from Malokamyshevatske, Iziumske and Sinichino-Yaremovske deposits can be treated as minerals for ferrophosphorus smelting. Keywords: ferrophosphorus, ore substance, phosphorite, mineral varieties, petrography, apatite
Highlights
As is commonly known, phosphorus and sulphur are generally considered to be harmful elements, and their content in steel must be as low as possible
Phosphorus appears to be among alloying elements, and its positive effect as an alloying element in low carbon steel has been known for a long time
The mineral composition was studied on the scanning electron microscope equipped with the attachment for the energy-dispersive X-ray spectroscopy with the software for calculating the chemical composition of the studied sample microvolume
Summary
Phosphorus and sulphur are generally considered to be harmful elements, and their content in steel must be as low as possible. Phosphorus, along with alloying elements, can be useful. Phosphorus appears to be among alloying elements, and its positive effect as an alloying element in low carbon steel has been known for a long time. Phosphorus content of 0.025% in 14 Cr-15 Ni steel contributes to a significant increase in the creep strength of the alloy [1]. The studies [3]-[5] proved a positive effect of phosphorus (from 0.01 to 0.20% wt) on the strength-ductility balance in steels cast on continuous casting machines
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