RU2021027C1 - Mechanical classifier - Google Patents

Abstract

FIELD: enrichment of mineral resources. SUBSTANCE: classifier is in the form of sloped trough with charging branch pipe, drainage threshold and discharging device with gate and outlet port, sand transportation gear positioned inside the body. Discharging device is mounted as viewed from charging branch pipe and is positioned between drainage threshold and charging branch pipe. Lower cut of drainage port is positioned lower than pulp level in the body. EFFECT: enhanced operating reliability. 2 dwg, 1 tbl

Description

 The invention relates to the classification of materials and can be used in mineral processing.

 The spiral classifier is known and widely used, which is an inclined trough with a spiral rotating inside to transport sand and a drain threshold. The process of hydraulic classification in a spiral classifier is based on the phenomenon of equidistance of grains in a liquid (Stokes law) [1].

 A disadvantage of the known spiral classifier is a significant difference in the particle size of the heavy mineral of the valuable component (columbite-tantalite) and lightweight grains (see table), which is especially evident in the processing of ores of rare and precious metals.

 The data in the table indicate that the content of the valuable mineral (columbite-tantalite) increases with decreasing size classes. More than 70% of Ta is concentrated in classes thinner than 0.063 mm. T.O. in the discharge of the classifier, due to the phenomenon of equidivisibility, density separation occurs - larger particles are represented by low density empty rock, and a heavy mineral is represented by small grains. Large grains of heavy minerals are deposited in the form of sand and fed to regrinding. Repeated return of heavy minerals to the mill leads to overgrinding and losses with sludge.

 The closest to the proposed technical essence and the achieved result is a mechanical classifier equipped with a vortex generator, in addition to the trough with a spiral and a drain threshold, which allows one to receive drain, sands, and also a classification intermediate product [2].

 However, this design of the classifier provides for the separation of intermediate grains after overcoming the septum, which does not allow large open grains of heavy minerals to get into the intermediate product. In addition, the classifier is distinguished by the complexity of the design, which complicates its manufacture and operation.

 The aim of this invention is to increase the extraction of metal by reducing the regrinding of large open grains of a valuable mineral, followed by extraction by gravity methods.

 The goal can be achieved in various ways. For example, food or sands of the spiral classifier can be screened on a screen, which involves the installation of additional equipment, dilution of products and their subsequent thickening. In general, this complicates the hardware design and operation.

 Conducted studies at the factory N 12 MRU found that with an increase in the depth of sampling of pulp from the trough of the classifier from the side of the loading pipe, the content of the useful component increases. Moreover, the content of tantalum in large classes is noticeably increasing. In addition, with an increase in depth, the content of thin classes and the amount of tantalum associated with them decrease by half. Consequently, the disclosed grains of columbite of nominal size are in suspension in the classifier at a depth of 100-400 mm. To achieve this goal, it is necessary to ensure the withdrawal of pulp from the trough of the classifier from a depth of 100-400 mm from the mirror.

 This goal is achieved by the fact that the proposed mechanical classifier is equipped with an unloading device with a gate mounted on the loading side of the classifier between the drain threshold and the loading nozzle, while the lower hole cut is located at a depth of not more than 400 mm below the level of the pulp in the classifier.

 With an increase in the hole depth over 400 mm from the pulp level, an increase in the nominal grain size to 3 mm and Ta associated product density is observed, which does not allow to efficiently separate metal by gravity methods.

 The invention is illustrated in figures 1 and 2.

 The mechanical classifier consists of an inclined trough 1, a rotating spiral 2, a drain threshold 3, a side unloading device 4 with a bottom valve 5 and a gate 6.

 The work of the mechanical classifier is as follows.

 The initial pulp through the loading pipe 7 enters the trough 1, where the process of hydraulic classification by equidistance occurs. Conditioned by size discharge, flowing over threshold 3, enters the flotation. Separated particles of the useful component by means of the gate 6 and the unloading device 4 are removed from the classifier and sent to gravitational enrichment in screw separators and concentration tables. The magnitude of the output stream and the size of the material is regulated by the gate 6. If necessary, stop the flow shut off by the bottom valve 5.

 In order to compare the effectiveness of both designs of classifiers, they were tested with subsequent gravitational production of concentrate.

 Compared with the baseline, the proposed classifier allows one to single out a product whose gravitational enrichment is more successful: tantalum extraction increased from 23.1 to 25.9%.

Claims (1)

 MECHANICAL CLASSIFIER, comprising a housing in the form of an inclined trough with a loading nozzle, a drain threshold and an unloading device with a slide in the outlet and a device for transporting sand located in the housing, characterized in that, in order to increase the efficiency of the classifier by increasing the extraction of metal and to reduce the regrinding of large open grains of a valuable mineral, the unloading device is installed on the side of the loading pipe and is located between the drain threshold and loading pipe, the lower section of the outlet is located below the slurry level in the housing.

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