EP2470306B1 - Method for the continuous magnetic ore separation and/or dressing and related system - Google Patents

Description

The invention relates to a method for continuous magnetic ore separation and / or treatment according to the preamble of claim 1. It should also be possible in particular a treatment of the substances used and a re-introduction into the process process.

In the relevant mining / reprocessing technology, ore is understood to mean a metal-containing rock from which the metal-containing constituents are to be separated as valuable substances. Especially in the case of copper ores, the valuable substances are in particular sulfidic copper materials which are to be enriched, for example - but not exclusively - Cu ₂ S. The Cu-free rock surrounding the material grains is referred to as matrix rock or gangue, in the professional world after grinding the rock also as tailing or hereinafter referred to as sand for short.

From the prior art, methods for ore separation are already known, which can optionally be carried out continuously. However, these methods mainly work on the principle of mechanical flotation, whereby the milled rock is mixed with water in order to process it further. This mixture of water and rock flour is also called pulp. The value ore particles in the pulp obtained in the pre-milled rock are first selectively provided with a hydrophobic layer with the aid of chemical additives and then concentrated via binding to air bubbles in a foam crown. The resulting mixture of ore particles, Foam bubbles and water can then be discharged in a simple manner in the overflow of so-called flotation cells.

In the prior art, in order to obtain a high degree of extraction of the ore fraction from the rock, i. To achieve a high yield, several successive separation stages are necessary, each containing its own flotation cells. But this is a total of great effort and continue to be particularly high energy consumption.

Magnetically assisted ore deposition methods have also been proposed, but are discontinuous in the related art. By performing as a batch batch process, the yield and the associated efficiency is limited, which affects the cost.
Other methods work continuously, such. B. drum, but have low mass flow rates because of the high mechanical complexity and maintenance requirements and are therefore not suitable for many of the mining operations used in mining.
The new method described below, however, can be used in addition to the magnetic ore deposition, where appropriate, for the treatment of water by means of the magnetic separation.

With older German patent applications of the Applicant methods for the continuous deposition of non-magnetic ores with the aid of magnetic or magnetizable particles are already proposed. For this purpose, reference is made to the following non-prepublished German patent applications of Siemens AG DE102008047841 and DE102008047842 as well as on the published W02009030669A2 of BASF AG.

In contrast, the object of the present invention is an overall process for the continuous magnetic ore deposition and in particular for the subsequent reprocessing indicate the substances used. For this purpose, a suitable system is to be created, which can be realized on a large scale in practice.

The object is achieved by the measures of claim 1. Further developments of the method are the subject of the dependent claims.

The invention thus relates to a continuous process for magnetic ore separation or treatment, including a reprocessing of the most important substances used. This results in a particularly environmentally friendly and economical overall process for the continuous separation of ores, in particular non-magnetic ores with the aid of magnetic particles, which can replace the conventional, complex flotation process as a whole.

The new process has a lower energy requirement and a higher extraction yield than the known processes and can in particular separate ore particles in a further particle size range than is possible according to the prior art. It is advantageous that an entire system can be largely composed of already available technical devices or facilities.

Further details and advantages of the invention will become apparent from the following description of an embodiment in conjunction with the claims.

Figur 1

ein Schaubild mit Funktionskästen für die einzelnen Verfahrensschritte mit den einzelnen Stoffflüssen und

Figur 2

eine konkrete Realisierung des Verfahrens gemäß Figur 1 in einer Gesamtanlage mit den notwendigen Einzelvorrichtungen/Einrichtungen zur Realisierung der Teilprozesse.

Show it

FIG. 1

a diagram with function boxes for the individual process steps with the individual substance flows and

FIG. 2

a concrete realization of the method according to FIG. 1 in an overall system with the necessary individual devices / devices for the realization of the sub-processes.

The two figures are described below largely together.

In the FIG. 1 the individual process sections are each registered in boxes with the associated chemical composition, the bold arrows indicate the respective sequence of process sections and the dashed lines with the respective arrows indicate the material flows from the recycled material.

Significantly methods described in the present and the associated system the use of magnetite (Fe ₃ O ₄₎ is provided as a magnetically-activatable sorbent: Magnetite is already hydrophobic in finely ground form, ie, it preferentially binds to hydrophobic particles in aqueous solutions.

The magnetite to be used is further treated in finely ground form with a surface modifying agent which makes the surfaces of the particles much more hydrophobic, i. water repellent, power. Hydrophobic particles agglomerate in aqueous suspension to minimize interfacial water. This is exploited to the extent that the ore particles are also selectively hydrophobized, but the gangue remains hydrophilic; This results in larger agglomerates of Werterzpartikeln and magnetite, which are magnetizable as a whole because of Magnetitanteils.

In the method described below, the magnetic properties of the magnetite are exploited by: can be separated from the nonmagnetic materials (gait) by means of defined magnetic fields or fields that can be activated by the magnetite with the value ore particles bound thereto. The following are examples of sulfidic copper minerals, the method can also be used for other sulfidic minerals such as molybdenum sulfide, zinc sulfide. By adapting the functional group of the hydrophobing agent for other minerals, the method described here can also be used for minerals of other chemical composition.

A major additive at the beginning of the process chain of the process is a long chain potassium or sodium alkylxanthate (hereinafter referred to simply as "xanthate"), an agent that is known to selectively adsorb to and render hydrophobic the surfaces of sulfidic copper minerals. The xanthate usually consists of a carbon chain with typically 5 to 12 carbon atoms and a functional head group that selectively binds to the copper mineral.
In the present case, this results in a hydrophobization of the value ore particles. For this purpose, the ore in finely ground form and water and diesel oil are used as input materials for the process described below.

According to Box 1, a mixture of the input materials takes place in a first process step. Here, the ore stream (pulp), which consists of the ground rock (ore), water and - depending on the application - different chemicals, mixed with the required already hydrophobized magnetite and the other water repellents, especially the xanthate. Preferably, the ore stream has a solids content of about 40 to 70 percent by mass, making the stream pumpable and accordingly FIG. 2 can be passed by means of a pump 25 in a mixing vessel or stirred tank 26.

The aim is that in an aqueous suspension (pulp), which in addition to the ore particles still contains the gangue, the Xanthat hydrophobized copper minerals, such as chalcocite (Cu ₂ S), bornite (Cu ₅ FeS ₄ ) or chalcopyrite (CuFeS ₂ ) with the hydrophobic magnetite (Fe ₃ O ₄ ^h ) agglomerates due to their water-repellent properties. This process step is referred to below as "load" process 2. As already shown, the hydrophobizing agent is used for the hydrophobization of the valuable material contained in the ore stream. The ore stream, the hydrophobizing agent and the magnetite are mixed together ("load process"). For this purpose, a mixing device or a stirred tank 26 is necessary, which must be carried out so that enough shear forces and residence time are available so that the hydrophobization reaction and the bringing together of magnetite and ore particles can take place.

A possible embodiment is a stirred tank 26, in which such a stirrer is used, which has high shear forces. The chemicals and the magnetite are metered in the vicinity of the stirrer. Such a stirrer must also be capable of ensuring not only local but also global mixing. It can alternatively be used an additional mixer, which also circulates the fluid. This produces large particles (agglomerates), which consist of hydrophobized resin and hydrophobized magnetite.

According to Box 3 is then followed by a separation of the ore into two streams, in particular the sulfidischen Werterzanteile the gait. In this step, in addition to the Stöffstrom "Tailing" (ie the largely freed from the Werterzanteilen gait) of the recyclable material "raw concentrate" generated. While tailing, as in the flotation processes used today, can be disposed of directly, the raw concentrate must be further processed in order to recover in particular the magnetite used and to prepare the copper mineral fraction accordingly for the subsequent further processing steps.

• der Magnetitstrom, der der Pulpe im Eingangsbereich der Anordnung (Kasten 1) zugeführt wird;
• das sog. Konzentrat, welches vorwiegend aus sulfidischen Kupfermineralien und einem gewissen Anteil an Gangart besteht.

For this purpose, according to Box 4, the water is first withdrawn; If required, an additional drying process takes place. According to Box 5, the mixture of the hydrophobic copper sulfide and magnetite is transportable, with a proportion of gait in the raw concentrate is still present as an impurity.
In further process steps, the magnetic component and the value-added component are separated from one another (so-called "unload" process). This in turn generates two streams:

• the magnetite flow which is fed to the pulp at the entrance of the assembly (box 1);
• the so-called concentrate, which consists mainly of sulfidic copper minerals and a certain amount of gangue.

The magnetite stream of recycled magnetite obtained in this way is additionally supplemented with fresh, hydrophobized magnetite in order to supplement the substance losses that are unimaginable in the overall process. This minimizes the need for comparatively expensive magnetite when carrying out the process, wherein the fresh magnetite is delivered in containers (eg "big balgs") and can be added as required.
Only to this stream, the other necessary chemicals are added in dissolved form. The chemicals are preferably added in dissolved form, because the metering and transport of liquids within the plant can be made more homogeneous, faster and more precise than the metering of solids.

In the lower part of the FIG. 1 is illustrated by the boxes 6 to 9, the separation of the copper sulfide-magnetite mixture. For this purpose, a non-polar liquid must be supplied to the mixture of sulphidic copper minerals, magnetite and gangue, as can be achieved, for example, by diesel oil.

The box 6 includes the supply of diesel oil to the final product according to box 5 and a related mixture of both substances. As a result, the agglomerates of sulfidic Minerals and magnetite broken up and created the opportunity to recover the magnetite and produce the actual product "concentrate" without Magnetitanteil.

In further process steps, the diesel oil on the one hand and the magnetite on the other hand are regenerated for further use. According to the dashed line with associated arrow, the magnetite, a part of the remaining in the raw concentrate gait, and diesel oil are returned to the input step.

The operation of the plant for carrying out the method is in FIG. 2 illustrated by the sequence of all devices / devices. Reference numeral 20 here denotes the container ("big bag") for the magnetite with a metering device 21. In a first process rail, the magnetite is mixed in a stirring device 22 with water and recycled magnetite. The mixture passes via a metering pump 23 into a stirring device 26, wherein the mixture Xanthat is supplied via a second metering pump 24. In a second process line, the valuable materials in the form of the pulp are fed with ore via a further metering pump 25 to the stirring device 26. The pulp and the mixture with xanthate are mixed in the agitator 46. The stirring device 26 is designed as a reactor and in this the "load" process is performed.

In the whole plant according to FIG. 2 There are two magnetic separators 30, 40, ie the process runs parallel in two process levels. The magnetic separators 30, 40 operate on the same physical principles. They each have a metering pump 27 and 39 assigned, which ensures the transport of the pulp. The aim of the magnetic separators 30 and 40 is to win a concentrate with a higher proportion of copper.

• ein so genannter Tailing-Strom, der einen wasserreichen Strom darstellt, und der - je nach Anwendung - entweder keinen Wertstoff mehr enthält und somit entsorgt werden kann. Gegebenenfalls enthält dieser Strom aber noch Restwertstoff und wird daher zur erneuten Bearbeitung zurückgeführt.
• Der abgeschiedene Strom ("Rohkonzentrat") enthält den Wertstoff als Zwischenprodukt in vergleichsweise hoher Konzentration. Dieser Strom enthält wenigstens 10 Massenprozent an Wertstoff und stellt einen Zwischenproduktstrom dar.

According to a first process, the mixture of ore and magnetite is fed to the separation process, for which purpose a metering pump 27 is necessary. In the actual separation process, the separation of the magnetic agglomerates from the ore stream, whereby separate streams arise and that is done

• a so-called tailing stream, which represents a stream rich in water and, depending on the application, either no longer contains valuable material and can thus be disposed of. If necessary, this stream still contains residual material and is therefore recycled for reworking.
• The separated stream ("raw concentrate") contains the valuable substance as intermediate in comparatively high concentration. This stream contains at least 10% by mass of valuable material and represents an intermediate product stream.

The latter intermediate product stream is subsequently passed with the aid of at least one metering pump 31 to a drying step. The drying can, if necessary, be carried out in two steps. In the first, indispensable step, most of the water is extracted by means of a mechanical process, in particular by centrifugal forces. Depending on the process, this water can be returned to the process, resulting in a largely closed water cycle with little impact on the environment. However, the separated water can also be fed back directly into the pulp preparation.

Another possible use is the admixture to the final product to make this transportable and, where appropriate, eliminate the effect of low residual moisture content.

One possible embodiment for the first dewatering step is the use of the decanter unit 32 according to FIG FIG. 2 , This produces the already mentioned intermediate product stream which still has at most 10 to 30% by mass residual moisture content.

This stream can, if necessary, for. B. be brought by means of a flexible screw conveyor 33 or a conveyor belt to a second drying step. This is, for example, a thermal dryer 34, which evaporates the remaining moisture. This dryer may e.g. operated by process steam or gas or oil burner. This creates steam that can be used elsewhere for preheating.

The latter step may become superfluous depending on the application and process management. From the dryer comes a stream of solids with a residual moisture of less than 1%. This stream is cooled in a solid heat exchanger 36 and added, for example by means of a screw conveyor 37 to another stirred tank 38.

In a particularly advantageous arrangement, the three process steps: coarse dehumidification-drying-heat dissipation are integrated in a single process unit, so that the number of apparatuses to be used in this step is reduced from three to one. In the stirred tank 38 according to FIG. 2 , which may preferably have a similar construction as the first stirred tank 26, the other chemicals, in particular the non-polar liquid such as diesel are admixed to the solids flow. It is necessary to choose chemicals that neutralize the hydrophobic bond between the recyclable material and the magnetite, which is ideally met by diesel. The diesel stream that is mixed in each case contains the recycled diesel oil and a fresh portion of diesel oil, which is necessary to compensate for material losses in the overall process. The diesel content must be at least 40 percent by mass in order to make the mixture flowable and pumpable. The diesel-containing mixture is passed with the aid of at least one metering pump 39 to the subsequent separation step, in which the magnetite particles are separated from the ore.

The "unload process" involves another magnetic separation. Thus, the magnetite is separated from the material flow, in order subsequently to be fed back to the "load process". This results in two streams: The one stream contains the valuable material (ore) and is dehumidified with the help of the decanter 44. Depending on requirements, another thermal dryer can be used. Thereafter, this mass flow is given by means of conveyors 44 in a stirred tank 46, mixed with water and output as a final product "concentrate" via a pump 47.

The magnetite stream is also dehumidified by means of a decanter 42. Here too, depending on the application, additional thermal drying steps may be added. Recovered diesel oil in turn is fed to the actual process, e.g. via the tank for diesel oil 50. The dry magnetite can be transported via a transport screw 43 to the stirring device 22. There, the recycled magnetite is mixed with fresh magnetite and water and returned to the material flow.

Claims (9)

1. Method for magnetic ore separation and/or dressing, in which metalliferous recoverable materials are separated from conveyed metalliferous ore rock, comprising the following method steps:

   - production of a liquid mixture (pulp) comprising water and ground rock, which contains the metalliferous recoverable material,

   - execution of a hydrophobising reaction of at least one recoverable material in the pulp,

   - synthesis of a hydrophobised, magnetisable, particulate material in liquid suspension and addition of this suspension to the pulp,

   - bringing about an agglomeration reaction between hydrophobised, magnetisable, particulate material and hydrophobised recoverable material to form magnetisable agglomerates in the pulp,

   - a first magnetic separation stage to separate the magnetisable agglomerates from the pulp

   - mixing of one of the separation products of the first separation stage, containing the agglomerates, with a non-polar liquid insoluble in water and decomposition of the agglomerates in the non-polar liquid into the basic components of magnetisable, particulate material and recoverable material,

   - a second magnetic separation stage to separate the magnetisable, particulate material from the recoverable material,

   - removal of moisture from the separation portion containing the recoverable material of the second separation stage to synthesise the recoverable material,

   characterised in that the materials used - magnetisable, particulate material, non-polar liquid and/or process water - are recycled.
2. Method according to claim 1, characterised in that magnetite (Fe₃O₄) is used as a magnetisable, particulate material.
3. Method according to claim 1 and 2, characterised in that a hydrophobising agent is used for selective hydrophobisation of the metalliferous recoverable materials of the pulp.
4. Method according to one of the preceding claims, characterised in that diesel oil is used as a non-polar liquid.
5. Method according to one of the preceding claims, characterised in that the moisture is removed from a material flow of the second magnetic separation stage, which comprises the magnetisable, particulate material, and the magnetisable, particulate material from which the moisture is removed is used to create the suspension.
6. Method according to one of the preceding claims, characterised in that xanthates are used as hydrophobising agents.
7. Method according to one of the preceding claims, characterised in that the pulp has a water content of 30 to 60 percent by mass.
8. Method according to one of the preceding claims, characterised in that the pulp is pumped.
9. Method according to one of the preceding claims, characterised in that additional chemicals are used in the pulp.

Images