RU2290998C2 - Method for concentration of mixed iron ores - Google Patents

Abstract

FIELD: process for concentration of iron ores, may be used in mining and metallurgical industry.

SUBSTANCE: method involves grinding basic ore; classifying ground material into sands and discharge fractions; providing additional grinding of sands and returning additionally ground sands for classifying of additionally ground material; providing primary desliming of discharge fraction; performing main magnetic separation for producing of rough concentrate and tailings; separating concentrate and tailings at final magnetic separation stage; filtering concentrate; subjecting discharge fraction resulted from classification of ground material to control classification; directing control classification sands for main magnetic separation; directing rough concentrate for rough concentrate classification and providing additional grinding of sands at second additional grinding stage; returning additionally ground sands for classification of rough concentrate of main magnetic separation; directing discharge of rough concentrate classification of main magnetic separation for primary stage of discharge desliming process; directing condensed primary desliming stage product for further magnetic separation in order to produce concentrate adapted to be directed for classification and additional grinding of classification sands at third additional grinding stage; directing control classification discharge and rough concentrate classification discharge of further magnetic separation for further desliming stage; directing condensed product of further desliming process for final magnetic separation; discharging magnetic separation tailings into final tailings.

EFFECT: increased efficiency in concentration of mixed iron ores.

4 cl, 1 dwg, 1 tbl, 1 ex

Description

The invention relates to the concentration of iron ores and can be used in the mining and metallurgical industries.

There is a method of ore dressing, including grinding the source material in a partially closed cycle, verification and control classification of the crushed material into sands and discharge, regrinding of sands with the return of sand to grinding or classification [1].

The disadvantage of this method is the low efficiency of enrichment associated with the regrinding and sludging of ore minerals

Closest to the claimed method is known for the enrichment of mixed iron ores, including grinding the original ore, stage-by-stage classification of the crushed material into sands and plums, regrinding sands with the return of regrind sands to classification, deslaming the discharge, magnetic enrichment of the desulphurized product to obtain a magnetic product and tailings, isolation supply of the last stage of magnetic enrichment of the fine fraction, deslaming it to obtain concentrate and tails, while the concentrate is combined with a magnetic product and sent to the filtration, moreover, the deslimated product of the previous stage is subjected to classification with obtaining granular and fine fractions, and the fine fraction is combined with the discharge of the subsequent classification stage [2].

The disadvantage of this method is the low efficiency of the enrichment process. Classifier discharge is divided into coarse-grained and fine fractions according to size classes in the control classification stage, and coarse-grained sands are crushed in a closed cycle in a grinding mill to a fineness of 50 μm, this leads to overgrinding of iron-containing minerals, a significant slimming of the control classification, a decrease in the performance of enrichment technology and an increase in loss of ore minerals. The combination of fine fractions of the classification of the de-slurred product and the discharge of the subsequent classification stage also leads to the sludge of the concentrate.

The technical result of the invention is improving the efficiency of the enrichment process, increasing the productivity of technological equipment and reducing the loss of useful component.

This is achieved by the fact that the method of enrichment of mixed iron ores includes grinding the initial ore, classification of the crushed material into sands and drains, regrinding of sands with the return of refined sands to the classification of crushed material, the primary stage of de-sludging of the drain, the subsequent stage of de-sludge separation of the drain, the main concentrate and tails, separation on the final magnetic separation of concentrate and tails and filtration of the concentrate. Drain classification of crushed material is subjected to control classification. Sands of control classification are sent to the main magnetic separation. The draft concentrate is sent to the classification of the draft concentrate with regrinding of sands in the second stage of regrinding and the return of refined sands to the classification of the draft concentrate of the main magnetic separation. At the primary stage of de-slamming the discharge, the classification of the draft concentrate of the main magnetic separation is drained. The thickened product of the primary de-slurry stage is sent to the subsequent magnetic separation to obtain a concentrate that is sent to the classification with regrinding sands of classification in the operation of the third stage of regrinding, and the discharge of the control classification and the classification of the draft concentrate of the subsequent magnetic separation are fed to the subsequent stage of de-slurry, and to the final magnetic separation serves the condensed product of the subsequent deslamination. Magnetic separation tails are discharged to dump tails.

The control classification is carried out by gravity flow or by soil pumps and is carried out in hydraulic classifiers or by means of thin screening.

The final magnetic separation concentrate is subjected to a control classification, which is performed in hydrocyclones with the return of hydrocyclone sands for grinding the second or third stage of regrinding or in a separate section.

The method is illustrated in the diagram.

The method of beneficiation of magnetite ores is as follows.

Mixed iron ore of current production is crushed and subjected to staged classification to obtain sand and discharge. The staged classification is carried out in two stages. Initially, classification is carried out in a spiral classifier with regrinding of sands in a closed cycle. The classification drain is subjected to a control classification according to a given size class, while the sands of the control classification are subjected to the main magnetic separation to obtain tails and a rough concentrate. The discharge of the control classification is sent to the next stage of deslamination with the release of tails and condensed product. The rough concentrate is sent to the classification, the sands of which are crushed in a mill of the second stage of regrinding, with the crushed rough concentrate being returned to the main magnetic separation for classification, and the plums - to the primary stage of de-cladding. The thickened product of the primary stage of de-slurry is sent to the subsequent magnetic separation to obtain a concentrate, and the discharge to the tailings. The classification of the draft magnetic separation concentrate is carried out in hydrocyclones, the sands of which are refined in the mill with a return to classification, and the discharge is combined with the discharge of the control classification and de-slurred in the subsequent stage of de-sludging. The thickened product of the subsequent de-slurry is subjected to final magnetic separation. The magnetic product of the final magnetic separation is classified in hydrocyclones with the return of the sands to regrinding, and the plums of all operations and the magnetic separation tails are removed to dump tails.

As a rule, the discharge of the control classification is represented by thin open ore minerals and slimy particles of non-metallic minerals. The sands of the control classification are represented by large open ore minerals, intergrowths of ore and non-metallic particles. The table shows the results of the control classification of the discharge of the classifier, followed by the process of deslamination and magnetic separation.

Control classification products Mass fraction,% Exit, % Mass fraction of iron in the product of magnetic separation,% solid class - 44 microns gland magnetic product tails concentrate yield food 40.8 49.8 39.2 100.0 drain 23.8 94.7 33.2 38.5 64.8 22.2 25.4 sands 78.0 21.7 43.0 61.5

The control classification of the classifier discharge according to a given size class minus 44 μm allows to isolate up to 38.5% of the discharge with an iron mass fraction of 33.2%. In the process of desliming and magnetic separation, a crude concentrate with a mass fraction of iron of 64.8-65.0% was obtained with a yield of 25.4%.

As a result of the implementation of the specified method of beneficiation of mixed magnetite ores, the loss of ore minerals in the stages of stage dressing is reduced, the load on volumetric nutrition in the grinding and magnetic separation cycles is reduced, the amount of material in the circulating loads of the grinding mills is reduced, the productivity of technological equipment is increased and, in general, the efficiency increases enrichment process.

An example of the method.

In this example, hydrocyclones are used as the classification equipment of the control classification. The initial mixed iron ore with a mass fraction of iron of total 39.5% and magnetite 20.5% was ground sequentially in a mill MSHRU 45 × 60 operating in a closed cycle with a spiral classifier 1KSN-30, then in a mill MSHC 45 × 60 in a closed cycle with GC-500 hydrocyclones and in the mill MSC 45 × 60, operating in a closed cycle with GC-360 hydrocyclones. The discharge of the 1KSN-30 spiral classifier was sent to the control classification in the GTs-500, the sands of which were sent to the magnetic separation of the first stage of the MMS to PBM 120/300 separators, and the discharge to the second stage of deslamination to deslamers MD-9 (No. 2). The rough concentrate of magnetic separation was sent for classification into hydrocyclones GC-500, the discharge of which was sent to the first stage of lacquering into magnetic desulphants MD-9 (No. 1), and the sands for regrinding. The thickened product of the first stage of dehumidification was subjected to magnetic separation in the third stage of MMS using PBM 120/300 separators, the draft concentrate of which was sent for classification in the GC-360 with regrinding in the mill MSC 45 × 60, and the discharge was combined with a discharge of the control classification GC 500 and sent to the second stage of de-slamming into deslamators MD-9 (No. 2). The thickened product of the second stage of de-cladding was subjected to magnetic separation in the fifth stage on PBM 120/300 separators to obtain the final concentrate. The final concentrate was sent for filtration.

The implementation of the method of beneficiation of mixed iron ores can be carried out using as classification equipment control classification of vibrating screens of fine screening.

Implementation of the proposed method allows to increase the yield of concentrate by 0.9% due to the separation of iron-containing minerals without over-grinding, to reduce the iron content in the tailings by 0.8%, to increase the extraction of iron into concentrate and, in general, the efficiency of the process of enrichment of mixed iron ores.

Information sources

1. Razumov K.A., Perov V.A. Design of processing plants. M .: Nedra, 1982, p. 81-91.

2. RF patent No. 2097138, cl. B 03 C 1/00, 1999.

Claims (4)

1. A method of enrichment of mixed iron ores, including grinding the original ore, classification of the crushed material into sands and plums, regrinding of sands with the return of regrind sands to the classification of crushed material, the primary stage of de-slurry discharge, the subsequent stage of de-slurry discharge, the main magnetic separation with obtaining tails, separation on the final magnetic separation of the concentrate and tailings, filtration of the concentrate, characterized in that the discharge classification is crushed the material is subjected to a control classification, the sands of the control classification are sent to the main magnetic separation, the rough concentrate is sent to the classification of the rough concentrate with regrinding of the sands in the second stage of regrinding and the regrind of the refined sands to the classification of the rough concentrate of the main magnetic separation, while the primary stage of de-classification is fed primary magnetic separation crude concentrate, condensed product of the primary stage of de-slurry I am directed to the subsequent magnetic separation to obtain a concentrate directed to the classification with regrinding of the classification sands in the operation of the third stage of regrinding, and to the subsequent stage of desliming the discharge, the control classification is drained and the classification of the rough concentrate of the subsequent magnetic separation is drained, while condensed is fed to the final magnetic separation the product of the subsequent desliming and the tails of the magnetic separations are discharged into the tailings. 2. The method according to claim 1, characterized in that the control classification is carried out by means of a gravity flow scheme or soil pumps. 3. The method according to claim 1, characterized in that the control classification is performed in hydraulic classifiers or by thin screening. 4. The method according to claim 1, characterized in that the final magnetic separation concentrate is subjected to a control classification, which is performed in hydrocyclones with the return of hydrocyclone sands to grinding the second or third stage of regrinding or to a separate section.