Enrichment of magnesite sievings from the Satkinsk deposits

Abstract

At the Magnesite Combine a department for the dressing of Satkinsk ares in heavy suspensions is currentiy in operation [i].The production schedule of this department includes sieving the original ores Ln~o fractions of !50-60, 60-78, and 8-0 mm; the first two fractions are dressed in heavy suspensions in drum and conical separators. ~he 8-0 mm sieve fraction, of which the original ore produces 20-25%, has a concentration of 1.8-5.2%* of CaO and 1.0-3.5% of SiO 2 and is not dressed; it cannot, in general, be used in the production of refractories in accordance with the production instructions currently valid at the Magnesite Combine. The development of an effective system of dressing this sieve fraction would make it possible to bring into production some additional magnesites which at present are stored in dumps.~lhe Sibelectrostal' Plant has developed a gravitation-flotation method for dressing this sieve fraction; this includes the wet screening into 8-0.6 and 0.6-0 mm fractions, the separation of the 8-0.6 mm fraction in a low-pressure hydrocyclone in a heavy suspension [2], and foam separation of the 0.5-0 mm fraction ( Fig. 1).Tae gravitation part of the process was checked in semiindustrial conditions using a sample of 370 tons with a 44.47% concentration of MgO, 3.3% of CaO, and 1.55% of SiO 2. During the tests the experimental dressing shop worked at a productivityof 4 tons/h in relation to the original feed. ~he 8-0.6 mm fraction was dressed in a suspension of density 2250 kg/m 3 in a low-pressure hydrocyclone, diameter 250 ram, mounted at an angle of 27 ~ to the horizontal. The input pressure was 49.03 kPa, the diameter of the sand nozzles 30 mm, and of the discharge nozzle, 60:ram. As the heavy agent we used ferrosilicium of grade Si-15 plus 5% of a magnetic concentrate to ensure the stability of the suspension. 2he suspension was regenerated by drainage and by washing out the heavy agent in self-balancing screens and by magnetic separation in a weak field.As a result of the dressing to give the gravel of the hydrocyclone, a Grade [II concentrate was separated; this amounted to 61.1%, with concentrations of CaO of 1.75% and of SiO 2 of 0.9%; the waste railings containing 13.3% CaO and 3.9% SiO2 were discharged.The additional processing of the 0.6-0 mm fraction was carried out by foam separation under laboratory conditions. From the original product, which contained 2.5% CaO and 2.04% SiO2, as a result of removal of 20 #m slurry (i.e., grains finer than 20 pm were removed) by means of the main separation and four repurifications, 11.1~ of Grade I concentrate was obtained; this contained 0.8% CaO and 0.37% SiO 2. Grade III concentrate (9.6%) was also obtained with a concentration of 1.86% CaO and 1.15% SiO 2. 2he yield of tailings (total with slurry) was 6.6% with a concentration of 6.3% of CaO and 6.2% of SiO 2.As a result of the dressing of the 8-0 mm sieve fraction, Grades I and III concentrates were obtained in amounts of 11.1 and 70.7% with a concentration of 0.8 and 1.77% CaO and 0.37 and 0.93% SiO...

Conditions of flotation of Satka deposit magnesite residue

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A method of concentration of Satka deposit magnesites in a heavy suspension has been developed by the Siberian Electric Steel Plant and by a flotation method by the plant together with the Ural Scientific-Research and Design Institute for Concentration and Mechanical Working of Minerals [i, 2].At present in the Magnesite Combine, which processes Satka ores, a section for concentration in heavy suspensions with a capacity of i million tons per year is in operation.A plant for development of the section specifies an increase in its capacity [3].The production plan for concentration includes screening into 150-60, 60-8, and 8-0 mm fractions and concentration of the first two fractions in heavy suspensions.The 8-0 mm residue is not concentrated.The yield of it is 20-25%* of the original ore and the calcium oxide content varies from 1.8 to 5.2% and that of silicon dioxide from 1.0 to 3.5%.At the Siberian Electric Steel Plant a study has been made of concentration of the residue by gravitation--flotation and flotation methods [4]. The highest quality concentrates were obtained by flotation.

A sample of residue of Satka magnesites taken at the Magnesite Combine in concentration of currently mined ore was investigated.

The primary minerals# of the sample are magnesite (84.5%) and dolomite (13%).

Calcite, talc, serpentine, quartz, carbon-containing compounds, sulfides, iron hydroxide, and magnetite are present in small quantities.

The magnesite has a light gray color and a microcyrstalline, fine to medium grain structure.

It is present in the form of 0.5-4.0 mm free grains (40%) and aggregates.

Both in the aggregates and in the magnesite grains there are observed inclusions of talc, serpentine, quartz, calcite, and carbon-containing substances from 0.004 to 0.i mm in size.

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“…At the Siberian Electric Steel Plant a study has been made of concentration of the residue by gravitation--flotation and flotation methods [4]. The highest quality concentrates were obtained by flotation.…”