Method for obtaining dehydrated mineral concentrate using ceramic disc vacuum filter

Abstract

FIELD: vacuum filters.SUBSTANCE: invention relates to the field of disk vacuum filters designed for separating liquid and solid phases of a suspension using ceramic filter elements, and can be used in ore enrichment processes. A method for obtaining dehydrated mineral concentrate is proposed, carried out using a disk vacuum filter with ceramic filter elements. According to the proposed method, a composition comprising ethoxylated propoxylated alcohol C12 and ethoxylated propoxylated alcohol C14, taken in mass fractions of 68-78% and 20-30% of the total mass of the composition, respectively, is introduced into an aqueous suspension comprising a mineral concentrate.EFFECT: increase in the productivity of a ceramic disc vacuum filter.1 cl, 3 dwg, 2 tbl, 8 ex

Description

Field of technology

[0001] The invention relates to the field of disk vacuum filters designed to separate the liquid and solid phases of a suspension using ceramic filter elements, and can be used in ore beneficiation processes. Background to the invention

[0002] The process of producing dewatered mineral concentrate from an aqueous suspension, the solid phase of which consists of particles of crushed feedstock ore characterized by a high content of the target mineral, is the final stage of a complex process known as "ore beneficiation" (hereinafter referred to as the beneficiation process). Hereinafter, this aqueous suspension is referred to as "pulp," and its solid phase as "mineral concentrate." Pulp is a product of an earlier stage of the beneficiation process, in which the mineral concentrate is separated from the crushed feedstock ore by flotation separation. Meanwhile, the liquid phase of the pulp is water with dissolved and suspended mineral salts, reagents used in earlier stages of the beneficiation process, and modifying additives that increase the efficiency of dewatering the mineral concentrate (hereinafter collectively referred to as water).

[0003] When producing dewatered mineral concentrate using a disc vacuum filter equipped with rotating sector filter elements, water is drawn through the permeable sidewalls of the filter elements, and the solid phase precipitate (cake) collected from the pulp and then dried is removed from the outer surfaces of these sidewalls (hereinafter referred to as the working walls). Hereinafter, the term "cake" refers to the mineral concentrate at all stages of its dewatering, beginning with the moment the filter element is lifted from the pulp.

[0004] Initially, disc vacuum filters were equipped with filter elements whose working walls were made of fabric (hereinafter referred to as fabric filter elements). However, due to significant vacuum leakage through extended seals and the inherently large distances between fabric fibers, disc vacuum filters with fabric filter elements are unable to reduce the moisture content of dewatered mineral concentrate to the required level. An acceptable result for using a disc vacuum filter with fabric filter elements is considered to be a dewatered mineral concentrate yield with a moisture content of 25-30% by weight of the total mass of the dewatered mineral concentrate, which requires energy-intensive measures such as additional drying.

[0005] Patent publication US4207186A, June 10, 1980, discloses a method for producing dewatered mineral concentrate (hereinafter referred to as the known method), according to which, to improve moisture removal from the mineral concentrate collected from the pulp onto the working walls of the filter elements, a hydrophobic additive is first introduced into the pulp, creating a hydrophobic layer on the surface of the mineral concentrate particles. Applied to disc vacuum filters with fabric filter elements, the known method allows for a slight reduction in the moisture content of the dewatered mineral concentrate.

[0006] However, the downside of this known method is a significant reduction in the performance of the disc vacuum filter. This undesirable effect is due to the fact that hydrophobization of the surfaces of mineral concentrate particles weakens their bond with water, and therefore with each other, resulting in the filter elements absorbing and retaining less mineral concentrate. A reduction in the performance of a disc vacuum filter when a hydrophobic additive is added to the pulp is noted in patent publication US2009026145A1, January 29, 2009.

[0007] Meanwhile, modern disc vacuum filters utilize filter elements with ceramic working walls (hereinafter referred to as ceramic filter elements), which minimize vacuum leakage and, consequently, reduce the moisture content in the dewatered mineral concentrate to an impressive 7% by weight of the total weight of the dewatered mineral concentrate. Clearly, for the technological process of producing dewatered mineral concentrate, which is carried out using a disc vacuum filter with ceramic filter elements (hereinafter also referred to as a ceramic disc vacuum filter), the problem of additionally reducing the moisture content of the dewatered mineral concentrate is no longer a priority, and further optimization of this technological process can be aimed at increasing the productivity of the ceramic disc vacuum filter.

[0008] The technical problem posed to the invention is to find a technical solution capable of increasing the productivity of a ceramic disc vacuum filter. The essence of the invention

[0009] To solve the technical problem posed by the invention, a method for producing a dehydrated mineral concentrate is proposed, carried out using a disk vacuum filter with ceramic filter elements (hereinafter referred to as the proposed method). According to the proposed method, a composition containing ethoxylated propoxylated alcohol C is introduced into an aqueous suspension containing the mineral concentrate. 12 and ethoxylated propoxylated alcohol C 14 , taken in mass fractions of 68-78% and 20-30% of the total mass of the composition, respectively.

[0010] The technical result of the invention consists in increasing the performance of the ceramic disc vacuum filter.

[0011] The cause-and-effect relationship between the features of the invention and the stated technical result is as follows. The inventors hypothesized that if hydrophobization of the surfaces of mineral concentrate particles weakens the bond between the mineral concentrate particles, which is realized through the liquid phase of an aqueous suspension, then imparting hydrophilic properties to their surfaces could strengthen the bond between the mineral concentrate particles.

[0012] Furthermore, the inventors took into account the fact that, due to the extremely small cross-sectional area of ​​the pores in the working walls of ceramic filter elements, they (the pores) can become clogged with foam, which occurs both when the liquid phase of the aqueous suspension passes through the layer of mineral concentrate collected on the working walls and when the liquid phase of the aqueous suspension enters the pores themselves. The increased tendency of the liquid phase to form foam is explained by the presence of flocculants and other reagents used in the earlier stages of the beneficiation process. According to the inventors, a decrease in the intensity of foaming could contribute to an increase in the number of points of application of the force that holds the collected layer of mineral concentrate on the working walls, and which is caused by the difference in air pressure between the internal closed cavity of the ceramic filter element and the external environment.

[0013] Based on these considerations, the inventors searched for a composition that, on the one hand, would be capable of wetting the surfaces of mineral concentrate particles, and on the other hand, could suppress the foaming ability of the liquid phase of an aqueous suspension. During this search, it was found that a composition containing ethoxylated propoxylated alcohol C meets these criteria. 12 and ethoxylated propoxylated alcohol C 14 , taken in mass fractions of 68-78% and 20-30%, respectively, of the total composition weight (hereinafter referred to as the proposed composition). Test results confirmed that the proposed method increases the performance of the ceramic disc vacuum filter.

[0014] It should be noted that the proposed composition, offered on the market under the trade name SteNor 24E4P5, and possibly under the trade name ROKAnol L5P5, for which the ratio of ethoxylated propoxylated alcohols C 12 and C 14 The composition, which is not disclosed, is originally intended as a detergent for laundry, dishwashing, and other household and industrial uses. The potential for using the proposed composition to enhance the performance of a ceramic disc vacuum filter was established through analytical and experimental research by the inventors and is currently unknown.

[0015] In a particular embodiment of the invention, the proposed composition is introduced into an aqueous suspension in an amount of at least 80 grams of the proposed composition per 1 ton of aqueous suspension. This embodiment allows for the technical result of the invention to be achieved in its most pronounced form. Brief description of the drawings

[0016] The implementation of the invention will be explained with reference to the figures: Fig. 1 - schematic representation of a ceramic disk vacuum filter; Fig. 2 - schematic representation of a ceramic filter element in section, made by a plane in which the axis of rotation of the ceramic disk filter lies; Fig. 3 - schematic representation of the Bakor-Test test setup.

[0017] It should be noted that the shape and dimensions of individual elements depicted in the figures are conventional and are shown in such a way as to most clearly illustrate the functional relationships between the elements. Furthermore, to avoid unnecessary complexity of the figures, some relationships between elements obvious to a person skilled in the art may not be shown. Carrying out the invention

[0018] The implementation of the invention will be shown using the best examples of the implementation of the invention known to the authors, which do not create restrictions on the scope of protected rights.

[0019] Fig. 1 shows a schematic representation of a ceramic disk vacuum filter 1, with the help of which the proposed method can be implemented. An aqueous suspension 3 (hereinafter referred to as pulp 3) is poured into bath 2, the solid phase of which, referred to in this presentation as the "mineral concentrate," consists of particles of crushed initial ore, characterized by a high content of the target mineral and pre-separated from the crushed initial ore. The target mineral in this case is a metal that is the final object of processing the initial ore, for example, a non-ferrous metal (copper, gold, etc.) or iron. In turn, the liquid phase of pulp 3 consists of water with dissolved salts, reagents from previous technological processes and additives described below.

[0020] The filter discs 10 are partially immersed in the pulp 3, and are capable of rotating clockwise around a horizontal axis. Each filter disc 10 is formed by a plurality of ceramic filter elements 11, made in the form of sectors of the filter disc 10 and, when mounted, secured to a rotating shaft 4. Each ceramic filter element 11, in turn, contains two side walls 12 (hereinafter referred to as working walls 12), the outer surfaces of which are located perpendicular to the said horizontal axis, while between the working walls 12 there is a closed cavity 13 (Fig. 2).

[0021] The working walls 12 are made of water-permeable porous ceramics, the pores of which pass through the entire thickness of the working walls 12, and essentially represent capillary channels connecting the outer surfaces of the working walls 12 with a closed cavity 13. By means of a tube 14, the closed cavity 13 is connected either to a pneumatic-hydraulic system 20, including a vacuum pump 21, a liquid pump 22 and a vacuum receiver 23, or to a hydraulic system 30 containing a pressure pump 31. Switching of these connections is ensured by means of a distribution mechanism (not shown) and is carried out automatically at each filtering cycle in accordance with the phase of rotation of the ceramic filter element 11. The vacuum pump 21 pumps air out of the vacuum receiver 23 and maintains a given vacuum level in it.

[0022] At the moment when the ceramic filter element 11 during its rotation around the mentioned horizontal axis is immersed in the pulp 3, the closed cavity 13 is connected to the pneumatic-hydraulic system 20 by means of a tube 14, and a vacuum is formed in the closed cavity 13. As a result of the resulting pressure difference between the outer and inner surfaces of the working walls 12, as well as the action of the capillary effect of the pores, the liquid phase of the pulp 3 (hereinafter referred to as the filtrate) begins to seep into the closed cavity 13, from where it enters the vacuum receiver 23 and is removed by means of the liquid pump 22. At the same time, the particles of mineral concentrate contained in the pulp 3, carried away by the filtrate flow, adhere to the outer surfaces of the working walls 12 in the form of a sediment, which, when the ceramic filter element 11 is raised from the pulp 3, turns into a cake.

[0023] When the ceramic filter element 11 rises from the pulp 3, maintaining a vacuum in the closed cavity 13, which now ensures that the cake is held on the outer surfaces of the working walls 12 and dried, continues until the ceramic filter element 11 again approaches the bath 2. In the area of ​​approaching the bath 2, the ceramic filter element 11 passes between two knives 5 (Fig. 2), cutting off a layer 7 of cake from the outer surfaces of both working walls 12 into a container 9, from which the cake, as a dewatered mineral concentrate, enters the conveyor and is removed from the beneficiation process.

[0024] After this, via tube 14, a short-term connection is made between closed cavity 13 and hydraulic system 30, the injection pump 31 of which supplies water under increased pressure into closed cavity 13, performing backwash of the pores of the working walls 12, removing particles stuck in them and completing the filtering cycle.

[0025] According to the proposed method, a composition containing ethoxylated propoxylated alcohol C is introduced into the pulp 3 before the start of the filtering cycle. 12 and ethoxylated propoxylated alcohol C 14 , taken in mass fractions of 68-78% and 20-30%, respectively, of the total mass of the composition, i.e., the proposed composition. Preferably, the proposed composition is to be introduced into pulp 3 in an amount of at least 80 g per ton of pulp 3.

[0026] Since the proposed composition is capable of ensuring the wetting of the surfaces of the mineral concentrate particles, the bond between the mineral concentrate particles in the cake layer 7, carried out through the liquid phase, is strengthened. In addition, since the proposed composition is capable of suppressing foaming in the liquid phase, then, due to the increase in the number of open pores of the working walls 12, which (open pores) are the points of application of the force attracting the cake layer 7 to the outer surfaces of the working walls 12, the bond between the cake layer 7 and the outer surfaces of the working walls 12 is strengthened. Taken together, these effects make it possible to accumulate and then retain a thicker cake layer 7 on the outer surfaces of the working walls 12, and therefore increase the productivity of the ceramic disk vacuum filter 1.

[0027] The predicted increase in the performance of the ceramic disk vacuum filter 1, achieved by using the proposed method, based on analytical research, was experimentally confirmed. The results of experiments conducted on examples of using the proposed method (hereinafter referred to as Examples) were compared with the results of experiments conducted without using the proposed method (hereinafter referred to as Comparative Examples). The "Bakor-Test" 70 test facility (hereinafter referred to as test facility 70) shown in Fig. 3 was used to conduct the experiments.

[0028] The test setup 70 contains a vacuum receiver 71, an electric motor 72, a container 73 with pulp 74 and a ceramic filter element 75, which is similar to the ceramic filter element 11 shown in Fig. 1. By means of vacuum silicone hoses, the vacuum receiver 71 is connected on one side to the ceramic filter element 75, and on the other side to the electric motor 72, which is capable of pumping air out of the vacuum receiver 71. When the tap 76 is open, the vacuum receiver 71 is capable of creating a vacuum in the closed cavity of the ceramic filter element 75, which is close to the vacuum created by the vacuum pump 21 in the closed cavity 13 (Fig. 1).

[0029] When conducting the experiment, tap 76 is opened and ceramic filter element 75 is immersed in pulp 74 for a time corresponding to the time of immersion of ceramic filter element 11 in pulp 3 during the filtering cycle carried out by ceramic disk vacuum filter 1. Then, with tap 76 open, ceramic filter element 75 is removed from pulp 74 and kept in air for a time corresponding to the time it takes for ceramic filter element 11 to pass from pulp 3 to knives 5. After this, tap 76 is closed, cake is scraped off the working walls of ceramic filter element 75, and its weight and moisture content are determined.

[0030] Comparative example 1 A vacuum of -0.85 bar was provided in the vacuum receiver 71. The ceramic filter element 75 was a Type 6 ceramic filter element manufactured by NTC Bakor LLC with a pore size of 1.2-1.5 μm and a total outer surface area of ​​the working walls of 0.03 m 2The immersion time of ceramic filter element 75 in pulp 74 and the subsequent exposure time of ceramic filter element 75 in air with vacuum applied were set at 20 and 30 seconds, respectively. Gold-bearing concentrate pulp from Bogolyubovskoye LLC (Novoangarsk Processing Plant) was used as pulp 74. The weight of the cleaned cake was recalculated based on the specific productivity of the ceramic disk vacuum filter (kg / m3). 2 *h), the value of which, together with the value of the cake moisture content, was entered into Table 1.

[0031] Example 1.1 The experiment was conducted similarly to Comparative Example 1, with the only difference being that the SteNor 24E4P5 reagent manufactured by NORCHEM LLC was added to the pulp at a rate of 80 g of reagent per 1 ton of pulp. According to the manufacturer, the SteNor 24E4P5 reagent contains ethoxylated propoxylated alcohol C 12 and ethoxylated propoxylated alcohol C 14, taken in mass fractions of 68-78% and 20-30% of the total mass of the reagent, respectively, i.e. is identical to the proposed composition.

[0032] Example 1.2 The experiment was carried out similarly to Comparative Example 1, with the only difference being that the reagent SteNor 24E4P5 produced by NORCHEM LLC was added to the pulp at a rate of 100 g of reagent per 1 ton of pulp.

[0033] Example 1.3 The experiment was carried out similarly to Comparative Example 1, with the only difference being that the reagent SteNor 24E4P5 produced by NORCHEM LLC was added to the pulp at a rate of 200 g of reagent per 1 ton of pulp.

[0034] Table 1 Consumption of reagent SteNor 24E4P5, g / t Specific productivity, kg / (m2*h) Humidity, % Comparative example 1 0 1193 6,8 Example 1.1 80 1211 6,9 Example 1.2 100 1307 6,9 Example 1.3 200 1248 6,9

[0035] Comparative example 2The experiment was carried out similarly to Comparative example 1, with the only difference being that the copper concentrate pulp from PJSC MMC Norilsk Nickel was used as pulp 74, and the values ​​of the specific productivity of the ceramic disk vacuum filter and the cake moisture content were entered into Table 2.

[0036] Example 2.1 The experiment was carried out similarly to Comparative Example 2, with the only difference being that the SteNor 24E4P5 reagent was added to the pulp at a rate of 80 g of reagent per 1 ton of pulp.

[0037] Example 2.2 The experiment was carried out similarly to Comparative Example 2, with the only difference being that the SteNor 24E4P5 reagent was added to the pulp at a rate of 100 g of reagent per 1 ton of pulp.

[0038] Example 2.3 The experiment was carried out similarly to Comparative Example 2, with the only difference being that the SteNor 24E4P5 reagent was added to the pulp at a rate of 200 g of reagent per 1 ton of pulp.

[0039] Table 2 Consumption of reagent SteNor 24E4P5, g / t Specific productivity, kg / (m2*h) Humidity, % Comparative example 2 0 907 12,5 Example 2.1 80 963 11,9 Example 2.2 100 1007 12,1 Example 2.3 200 1011 12,2

[0040] As can be seen from Tables 1 and 2, when using the proposed method (Examples 1.1-1.3 and 2.1-2.3), the performance of the ceramic disk vacuum filter increases relative to cases in which the proposed method was not used (Comparative Examples 1 and 2).

[0041] An unexpected effect revealed by the experimental results consists of a negligible increase in cake moisture content in Examples 1.1-1.3 relative to Comparative Example 1, and even a slight decrease in cake moisture content in Examples 2.1-2.3 relative to Comparative Example 2. The absence of the expected increase in cake moisture content is presumably explained by the increase in the number of open pores in the working walls of the ceramic filter element 75, which became possible due to the suppression of foaming in the liquid phase of the pulp provided by the proposed composition. The increased number of open pores made it possible to intensify the outflow of water from the cake layer and thereby compensate for the difficulty in separating water from the surface of individual particles of the mineral concentrate, caused by the increased wetting properties of the proposed composition.

Claims

1. A method for obtaining a dehydrated mineral concentrate, carried out using a disk vacuum filter with ceramic filter elements, in which a composition containing ethoxylated propoxylated alcohol C is introduced into an aqueous suspension containing a mineral concentrate 12 and ethoxylated propoxylated alcohol C 14 , taken in mass fractions of 68-78% and 20-30% of the total mass of the composition, respectively.

2. The method according to paragraph 1, in which the introduction of the composition into the aqueous suspension is carried out in an amount of at least 80 grams of the composition per 1 ton of the aqueous suspension.

Images