Flotation Method

Abstract

To provide an ore flotation method which can effectively manage the operation of ore flotation for ore including copper minerals.SOLUTION: The present invention provides an ore flotation method for pulp mixed with ore including copper minerals. The method includes acquiring image information of froth formed on the pulp surface, and using a color value of the froth obtained from the image information in the L*a*b* color space, to manage the operation of ore flotation.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This specification describes a flotation method for pulp mixed with ores containing copper minerals. [Background technology]

[0002] Flotation is used to separate copper minerals from ore containing the copper minerals. In this process, ore that has been pulverized in a previous process is mixed with a liquid such as water to form a pulp (sludge), and this pulp is stored in a flotation cell of a flotation device. A foaming agent to form a froth, a collector to float only the desired minerals, a pH adjuster, and other chemicals are then added to the pulp in the flotation cell and stirred. The froth floats, carrying the desired minerals, such as copper minerals, with it. The desired minerals that float in this way are recovered by overflowing the flotation cell together with the froth.

[0003] The timing of froth recovery after the start of flotation, the amount of recovery, etc. are usually managed by an operator who visually observes the properties of the froth that has risen to the pulp surface and checks measurement data such as the height position of the pulp surface and the height position of the froth on the pulp surface, etc. Based on such operator judgment, flotation operations are generally managed so as to recover as much copper mineral as possible and to obtain higher-grade copper concentrate.

[0004] On the other hand, Patent Document 1 describes the use of a camera and an image analysis system as a detector to measure the speed at which the froth overflows from the flotation cell. In Patent Document 1, it is stated that there is a correlation between the froth height and the supply gas flow rate to the flotation cell, and between the froth velocity and the supply gas flow rate, and that this correlation is used to calculate the optimal supply gas flow rate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2014 / 0110311 Summary of the Invention [Problem to be solved by the invention]

[0006] In the operational management of flotation, which relies on the visual inspection and judgment of workers, there is a concern that the response will vary depending on the worker, especially when the properties of the froth change, making it difficult to standardize.

[0007] Although Patent Document 1 describes a camera and an image analysis system for detecting froth overflow, it is difficult to say that such cameras are effectively used in actual operations. Furthermore, since the properties of froth differ depending on the type of ore, it cannot be said that operation management is possible simply by using a camera.

[0008] This specification provides a flotation method that can effectively manage flotation operations for ores containing copper minerals. [Means for solving the problem]

[0009] The above-mentioned flotation method is a flotation method for pulp mixed with ore containing copper minerals, and comprises obtaining image information of froth formed on the surface of the pulp, and calculating the L of the froth obtained from the image information. * a * b * This involves using color values ​​in a color space to control flotation operations. The ore used has a quartz content of 50% by weight or more. It is something. [Effects of the Invention]

[0010] According to the above-described flotation method, the flotation operation for ore containing copper minerals can be effectively managed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing an example of a flotation device that can be used in an ore flotation method according to one embodiment. [Figure 2] 2 is a schematic cross-sectional view showing two of the plurality of flotation cells provided in the flotation apparatus of FIG. 1. FIG. [Figure 3] FIG. 1 is a diagram illustrating an example of actual operation management. [Figure 4] 1 is a graph showing the relationship between the color value and the copper grade of a specific ore (sample A) in an example. [Figure 5] 1 is a graph showing the relationship between color value and copper recovery rate for a specific ore (sample A) in an example. [Figure 6] 1 is a graph showing the color value and copper recovery rate 10 minutes after the start of flotation before brightness adjustment in an example. [Figure 7] 1 is a graph showing the color value and copper recovery rate 10 minutes after the start of flotation after brightness adjustment in an example. [Figure 8] 1 is a graph showing the relationship between color value and copper grade when another ore (sample B) is used in an example. [Figure 9] 1 is a graph showing the relationship between the proportion of quartz in ore and the flotation rate. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the above-mentioned flotation method will be described in detail. In one embodiment, the flotation method includes, when flotation is performed on pulp mixed with ore containing copper minerals, acquiring image information of froth formed on the pulp surface, and calculating the L of the froth obtained from the image information. * a * b * This involves using color values ​​in a color space to control flotation operations.

[0013] This is because in ores containing copper minerals, especially primary copper sulfide ores in which silicon does not substantially float during flotation, the L of the froth in the froth image information * a * b *This is based on the new finding that there is a correlation between the color values ​​in the color space and the copper grade, etc., of the ore in the froth that has risen to the pulp surface (liquid surface). Utilizing this finding, the timing and amount of froth recovery can be determined based on the color values ​​in the froth image information, thereby enabling more effective management of flotation operations than relying on the visual inspection and judgment of workers. Furthermore, effective management of flotation operations may improve the copper recovery rate, leading to more effective utilization of mineral resources.

[0014] (ore) The ore to be subjected to flotation is an ore containing a copper mineral, and is obtained by, for example, crushing ore mined from a specified mine and then grinding it to a specified size. Also, tailings obtained by flotation or other ore-dressing methods for other minerals, or kalami obtained by dry smelting, can also be used as the ore to be subjected to flotation in this embodiment.

[0015] Such ores are classified as primary copper sulfide ores and secondary copper sulfide ores. Specific examples of copper minerals in primary copper sulfide ores include chalcopyrite, bornite, and enargite. Examples of copper minerals in secondary copper sulfide ores include chalcocite and covellite. Although not always subject to flotation, copper oxide ores also exist in ores containing copper minerals, which can cause contamination. Brochantite is an example of a copper mineral in copper oxide ores.

[0016] In particular, ores with a high content of primary copper sulfide ore are preferred. This is because it has recently been discovered that there is a strong correlation between the color value and copper content of such ores. The content ratios of copper oxide ore, primary copper sulfide ore, and secondary copper sulfide ore in the ore can be measured using a predetermined sequential analysis. This sequential analysis begins with copper oxide ore analysis, in which citric acid is added to a sample of the target mineral crushed to a certain particle size and stirred for a certain period of time. The amount of copper dissolved is quantified, which is defined as the amount of copper oxide ore (CuAC). Next, in secondary copper sulfide ore analysis, sodium cyanide solution is added to the solid fraction obtained by solid-liquid separation after copper oxide ore analysis and stirred for a certain period of time. The amount of copper dissolved is quantified, which is defined as the amount of secondary copper sulfide ore (CuCNS). Finally, for primary copper sulfide ore analysis, nitric acid and perchloric acid are added to the solid portion obtained by solid-liquid separation after secondary copper sulfide ore analysis, and the solid is dried on a hot plate. Hydrochloric acid and distilled water are then added to dissolve the solid, and the amount of dissolved copper is quantified, which is the amount of primary copper sulfide ore (CuINS). In each analysis, the amount of dissolved copper is quantified using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The proportions of copper oxide, primary copper sulfide, and secondary copper sulfide ore in the copper mineral may also be measured using an analytical device such as an MLA (Mineral Liberation Analyzer).

[0017] Typically, the ore may contain 0.30% to 1.50% by weight of copper. In addition, it may further contain 20% to 40% by weight of silicon and 1.00% to 5.00% by weight of iron. However, since the grade varies depending on the ore, it is not particularly limited to these.

[0018] In particular, it is preferable to target ores in which silicon content is substantially difficult to float during flotation, i.e., ores with 50% or more quartz by weight. This is because the correlation between the color value and copper content may be weak in ores in which silicon content is easily floated, i.e., ores with less than 50% quartz by weight. The content of minerals such as quartz can be determined by measuring with an MLA. To achieve reproducibility with the MLA, when observing samples to ensure a similar mineral composition, the samples embedded in resin should be observed vertically. It is also important to confirm that the elemental composition is similar.

[0019] For reference, similar flotation was performed on various ores with different quartz percentages, and the flotation rate of each ore was investigated. The results are shown in Table 1 and Figure 9. Table 1 and Figure 9 show that ores with a quartz percentage of 50% or less by weight (high clay content minerals) tend to have a higher flotation rate than ores with a quartz percentage of more than 50% by weight (low clay content ores).

[0020] [Table 1]

[0021] (flotation) To perform flotation, the ore described above is mixed with a liquid such as water or limewater to form a pulp, which is then stored in a flotation cell of a flotation device. Chemicals added to the flotation cell include a foaming agent to form a froth, a collector to increase the froth's ability to capture copper minerals, and, in some cases, an inhibitor to prevent other minerals from floating. Once a pH adjuster is added to the flotation cell to achieve a desired pH, the cell is aerated with forced or self-sufficient air, and the skimmer is rotated to collect the froth. Froth collection is sometimes accomplished by allowing the froth to naturally overflow from the flotation cell. The various chemicals described above may also be added in advance when preparing the pulp before it is placed in the flotation cell.

[0022] In this embodiment, in order to manage the flotation operation using image information of the froth on the surface of the pulp in the flotation cell, image information of the froth is acquired, for example, by installing a photographing device such as a camera above the flotation cell. The image information can be acquired by continuously photographing the froth or by photographing it intermittently at predetermined times. In other words, the froth is monitored by the photographing device.

[0023] The image information obtained as described above is transmitted to, for example, a computer, etc., where it is subjected to image analysis. In the image analysis, the L of the floss in the image of the image information is * a * b * Color space (CIE1976(L * ,a * ,b * This involves calculating the color value (i.e., Lab color) of the color space. This color value (i.e., Lab color) is calculated using the following formula (1):

[0024]

number

[0025] where L0, a0 and b0 are * a * b * Any coordinate in the color space can be set, but in most cases the standard white point is used. * , a * and b * is the L of the pulp surface in the image of the image information. * a * b * It is a coordinate in color space and can be calculated using image processing software, etc. The color value is calculated as the average color value of each pixel that makes up the part corresponding to the floss in the image of the floss image information over a specified period of time (for example, 5 seconds).

[0026] As mentioned above, there is a correlation between the color values ​​of the froth in the image in the image information and the copper content in the froth that floats to the pulp surface in the actual flotation cell. Therefore, the color values ​​can be used to estimate the copper content of the ore in the froth that is formed on the pulp surface when the image information is acquired. Furthermore, by determining the froth recovery time and / or the amount of froth recovered based on the color values, it is possible to standardize responses when the properties of the froth change, enabling stable operational management regardless of the operator. In addition, costs can be reduced by reducing labor costs.

[0027] More specifically, it is preferable to obtain multiple images of the froth in the flotation cell at predetermined time intervals and, from the images, obtain in advance a graph or other information relating to the relationship between the color value and the copper grade of the ore in the froth formed on the pulp surface. In this case, when image information of the froth is obtained in a subsequent flotation step, the color value can be calculated from the image information, and the copper grade of the ore in the froth on the pulp surface can be estimated based on the graph or other information relating to the relationship between the color value and the copper grade. Such information is not particularly limited, but may be, for example, a graph with the color value (Lab color) on the horizontal axis and the copper grade on the vertical axis.

[0028] L of the pulp surface obtained from image information * a * b * The color values ​​in the color space also correlate with the copper recovery rate.

[0029] In many cases, the color value decreases as the copper content of the froth in the flotation cell decreases. If the color value becomes zero during flotation, for example, before the cumulative copper recovery rate in the froth formed on the pulp surface reaches its maximum, it may become impossible to estimate the subsequent increase in cumulative copper recovery rate from the color value. Therefore, it is preferable to adjust the brightness of the pulp surface so that the color value does not become zero until a predetermined time has elapsed from the start of flotation, for example, by installing a lighting fixture that illuminates the pulp surface in the flotation cell or adjusting the output of the lighting fixture. More specifically, it is preferable to set the predetermined time to be equal to or longer than the time from the start of flotation to the time when the copper recovery rate in the froth formed on the pulp surface reaches its maximum. This makes it possible to effectively estimate the copper content, etc., using the color value described above over a required period of time.

[0030] For flotation, a flotation apparatus 1 as shown in Fig. 1 may be used. This flotation apparatus 1 is equipped with a plurality of flotation cells 2 arranged side by side from the upstream side to the downstream side (from left to right in Fig. 1), and adjacent flotation cells 2 are in communication with each other. More specifically, as shown in Figure 2, adjacent flotation cells 2 are connected to each other by a communication section 3 provided between them, which allows the flow of pulp P. Each communication section 3 is provided with a valve 4 that controls the flow of pulp P from the upstream flotation cell 2 (right side in Figure 2) to the downstream flotation cell 2 (left side in Figure 2). By operating this valve 4, the froth layer FL in the upstream flotation cell 2 can be varied. The froth layer FL is the height-wise region of the froth F formed on the pulp surface PS in the flotation cell 2, and here it is defined as the region between the overlip OL, which is the overflow portion, and the pulp surface PS.

[0031] In the illustrated flotation cell 2, when the valve 4 is closed, the pulp surface PS rises as pulp P flows in from the upstream flotation cell 2. As the pulp surface PS rises, much of the froth F on the pulp surface PS overflows the overlip OL and is recovered. When the valve 4 is closed in this way, the amount of recovered froth F increases, and the copper recovery rate also increases. On the other hand, when valve 4 is opened, pulp P flows out into the downstream flotation cell 2, causing a decrease in the pulp surface PS. When the pulp surface PS decreases, the amount of froth F that overflows beyond the overlip OL decreases. Therefore, opening valve 4 leads to a decrease in the amount of recovered froth F and, ultimately, a decrease in the copper recovery rate. In this way, in the flotation device 1 of the illustrated example, the amount of froth F recovered can be adjusted by opening and closing the valve 4.

[0032] Furthermore, since floss F basically contains a large amount of copper minerals, increasing the amount of floss F recovered tends to increase the copper recovery rate.

[0033] Here, in this embodiment, L is obtained from image information acquired about the floss F on the pulp surface PS in the flotation cell 2 before the floss F overflows beyond the overlip OL as described above. * a * b * The color value of the color space is calculated. As mentioned above, since there is a correlation between the color value of the froth F and the copper grade of the ore in the froth F, it is preferable to open and close each valve 4 between the plurality of flotation cells 2 based on this correlation, and set the froth layer FL of each of the plurality of flotation cells 2. More specifically, after starting flotation using the flotation apparatus 1, when the color value approaches the value at which the copper recovery rate is maximized, it is preferable to perform operational management by varying the froth layer FL so as not to collect too much float. This is because if further float is collected from the flotation cell after the maximum recovery rate has been achieved, the copper grade will decrease.

[0034] For example, consider a case where the above-mentioned color value-based operational management is not performed, as shown in Figure 3 under "1 Normal." In this normal case, the pulp level is set to 20 in all flotation cells. When image information of the pulp surface is acquired and its color value is calculated, the color values ​​for the flotation cells in each section are obtained as shown in "2 Camera Management." In this case, the color values ​​for the flotation cells in sections 1 and 2, 3 and 4, and 5 and 6 are relatively high, and it is considered that the maximum recovery rate has not yet been achieved. Therefore, in "3 Improving Recovery Rate through Color Value Management," the pulp level is increased (the distance between the pulp surface and the overflow area is narrowed from 20 to 10) to increase the amount of froth recovered. On the other hand, in the flotation cells in zones 7 and 8 under "2 camera control," the color value was small and it was thought that the maximum recovery rate had already been achieved, so the pulp level was lowered (the distance between the pulp surface and the overflow area was widened from 20 to 30) and the amount of recovered froth was reduced. This type of operational control can improve the final copper recovery rate when multiple flotation cells are used. [Example]

[0035] Next, a test was carried out to confirm the effectiveness of the flotation method described above, and the test will be described below. However, the description here is for illustrative purposes only and is not intended to be limiting.

[0036] (Relationship between color value, copper grade, and copper recovery rate) A specific ore containing copper minerals (sample A) was subjected to flotation using a flotation cell.

[0037] During flotation, images of the pulp surface in the flotation cell were taken multiple times, and the relationship between the color value calculated from each image and the copper grade and copper recovery rate in the froth at the time the image was taken was investigated. The results are shown in Figures 4 and 5. In the graphs of Figures 4 and 5, as described in the graph legend, the approximation curves of the circle plots are shown as solid lines, the approximation curves of the triangle plots are shown as short-dashed lines, and the approximation curves of the square plots are shown as long-dashed lines. 4 and 5 show that there is a correlation between the color value and the copper grade and copper recovery rate, respectively.

[0038] (Relationship between brightness and color value) In the flotation process described above, before the brightness adjustment, as shown in Figure 6, the copper recovery rate increased even though the color value was zero 10 minutes after the start of flotation. In contrast, when the brightness was adjusted to be darker, as shown in Figure 7, the color value did not reach zero after 10 minutes, making it possible to manage operations using the color value.

[0039] (Ore with easily floating Si content) When a similar flotation process was carried out using an ore (sample B) in which Si content is more likely to float than the ore (sample A) described above, no clear correlation was confirmed between the color value and the copper grade, as shown in Figure 8.

[0040] The mineral compositions of Sample A and Sample B used in the above-mentioned tests are shown in Table 2. It was confirmed that Sample B, which has a tendency for Si to float, contains less quartz than Sample A.

[0041] [Table 2] [Explanation of symbols]

[0042] 1 Flotation device 2. Flotation Cell 3 Communication section 4 valves P Pulp F floss FL Floss Layer PS pulp surface OL Overlip

Claims

1. 1. A flotation method for pulp mixed with ore containing copper minerals, comprising: Image information of the floss formed on the pulp surface is obtained, and the L of the floss obtained from the image information is * a * b * using color values ​​in a color space to control a flotation operation; A flotation method using an ore having a quartz content of 50% by weight or more as the ore.

2. 2. The method of claim 1, further comprising estimating the copper grade in the ore in the froth from the color value.

3. 3. The method of claim 1, further comprising obtaining information relating to the relationship between the color value and the copper grade in the ore in the froth from the image information.

4. The flotation method according to any one of claims 1 to 3, further comprising determining the time and / or amount of the froth to be recovered based on the relationship between the color value and the copper content of the ore in the froth.

5. 5. The method of claim 1, further comprising operating a valve in a flotation cell of a flotation device to set a pulp level in the flotation cell based on the relationship between the color value and the copper grade in the ore in the froth.

6. The flotation method according to any one of claims 1 to 5, comprising adjusting the brightness of the pulp surface so that the color value does not become zero until a predetermined time has elapsed from the start of flotation.

7. 7. The method of claim 6, wherein the predetermined time is set to be equal to or greater than the time from the start of flotation to the time when the copper recovery rate in the froth is maximized.

Images