JP6428829B2 - Bearing replacement time judgment method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a bearing replacement time determination method, and in particular, a bearing replacement time determination method suitable for application to life management of a bearing provided in an agitator of an autoclave device used in a high pressure acid leaching method. About.

  Nickel oxide ore has been considered difficult to use as a nickel resource because of its low nickel content. However, as a result of the development of a hydrometallurgical method using high-pressure acid leaching technology, for example, nickel-cobalt mixed sulfides (nickel grade of about 60% by mass) can be produced economically (for example, patents) Reference 1).

  As a hydrometallurgical method of nickel oxide ore, a high-pressure acid leaching method using an autoclave apparatus is known. The high pressure acid leaching method is performed, for example, through the following procedure.

  First, an ore slurry is prepared with a solid content of about 40% by mass and a solid content particle size of about 1.4 mm or less (see, for example, Patent Document 2). Next, the obtained ore slurry is heated and pressurized and supplied to the autoclave apparatus. In an autoclave device, sulfuric acid is added to ore slurry at high temperature and high pressure (for example, temperature of about 250 ° C., pressure 3.5 to 4.0 MPaG) and stirred to leach slurry containing valuable metal components (nickel, cobalt). Get. Next, by returning to room temperature and high pressure to remove unnecessary matters such as leaching residue, a leachate composed of nickel / cobalt mixed sulfide is obtained.

  The autoclave apparatus used in the high pressure acid leaching method includes a stirrer for stirring the ore slurry, and the stirrer is operated under high temperature and high pressure. The stirrer rotates a stirring blade attached to a rotating shaft by a driving force such as a motor. The rotating shaft of the agitator is rotatably supported by a bearing.

  The bearing of the agitator holds a load received from the rotating shaft while supporting the rotating shaft. For this reason, tapered roller bearings and double-row tapered roller bearings are used for the agitator bearings in order to maintain the load in the radial / axial direction and to support the rotating shaft. In such a bearing, peeling is generated by repeatedly applying a compressive stress to the raceway surfaces of the inner ring and the outer ring or the rolling surfaces of the rolling elements over a long period of time. Peeling means that when a rolling bearing is operated, when the viscosity of the lubricating oil decreases and the oil film breaks, or when the lubricating oil is insufficient, the raceway member and the rolling element are in direct contact with each other, This is a phenomenon in which minute peeling or cracking occurs on the surface of the film. If peeling progresses, it will lead to wear and large peeling. For this reason, if the use of the bearing is continued in a state where peeling has occurred, the rolling element is deformed, the cage is damaged, and finally an abnormality such that the agitator cannot be rotated occurs.

  When an abnormal rotation of the stirrer occurs, the administrator of the autoclave apparatus determines that the bearing of the stirrer has reached the end of its life. In that case, it is necessary to stop the operation of the plant including the autoclave and replace the bearing. For this reason, not only the operation efficiency is lowered, but also the cost required for the replacement parts cannot be ignored.

  In order to replace the bearing, pressure reduction / temperature reduction, which is an operation for stopping the operation, is required prior to that. Further, after the replacement of the bearing is completed, it is necessary to increase the pressure / temperature to start the autoclave device. For this reason, a series of operations including the stop operation of the autoclave apparatus, the replacement of the bearings, and the start-up of the autoclave apparatus took approximately 28 hours or more, and the influence on the operation was large.

  Here, as a technology related to the bearing, for example, Patent Document 3 describes a bearing with a vibration measurement terminal that detects minute vibrations of the bearing. Further, Patent Document 4 relates to a lubricant deterioration detection device for a bearing that detects a deterioration state due to contaminants contained in the lubricant enclosed in the bearing, and detects the lubricant in a discharge path for discharging the lubricant in the bearing. Techniques for providing sensors (optical foreign matter sensor, iron powder detection sensor, moisture detection sensor, etc.) are described.

JP-A-2005-350766 JP 2009-173967 A Japanese Patent Laid-Open No. 6-17826 JP 2008-139188 A

  However, in the technique described in Patent Document 3, when the rotation speed of the stirrer is low and the vibration of the bearing is small, the bearing fixing component may absorb the vibration. For this reason, even if a minute vibration that leads to an abnormal rotation of the bearing occurs, it is difficult to accurately detect this. As a result, the life management of the bearing cannot be properly performed, and it may be impossible to determine whether or not the repair is necessary even during the plant stoppage period.

  On the other hand, the technique described in Patent Document 4 focuses only on detecting the deterioration state of the lubricant, and a concrete response such as how the detection result is reflected in the life management of the bearing itself is disclosed. It has not been.

  A main object of the present invention is to provide a technique capable of appropriately managing the life of a bearing and reducing the number of sudden stops of the stirrer.

(First aspect)
The first aspect of the present invention is:
An acquisition stage for acquiring information indicating the relationship between the iron powder concentration in the grease in the bearing and the life of the bearing;
A measurement stage for measuring the iron powder concentration in the grease in the bearing to be diagnosed, with the bearing being used in the agitator as a diagnosis target,
Using the measurement value of the iron powder concentration obtained in the measurement step and the information obtained in the acquisition step, a determination step of determining a replacement time of the bearing to be diagnosed,
This is a method for determining the replacement time of a bearing including
(Second aspect)
The second aspect of the present invention is:
High pressure that stirs heated and pressurized raw material slurry and sulfuric acid with a stirrer in each of the plurality of compartments, and advances the leaching of valuable metals by sequentially transferring the slurry from the upstream compartment to the downstream compartment A bearing replacement time determination method applied to an autoclave device used in an acid leaching method,
The autoclave device includes a plurality of stirrers corresponding to the plurality of compartments, and each stirrer has a bearing,
An acquisition step of acquiring information indicating the relationship between the iron powder concentration in the grease in the bearing and the life of the bearing for each of the agitators,
A measurement step of measuring a bearing in use in at least one of the plurality of agitators as a diagnosis target, and measuring a concentration of iron powder in the grease in the diagnosis target bearing;
Based on the information obtained in the acquisition step, a setting step for setting an iron powder concentration threshold value for each of the stirrers as a criterion for determining the bearing replacement time;
Based on the measured value of the iron powder concentration obtained in the measurement step and the iron powder concentration threshold set corresponding to the stirrer having the diagnosis target bearing, the replacement time of the diagnosis target bearing A determination stage for determining
This is a method for determining the replacement time of a bearing including

  ADVANTAGE OF THE INVENTION According to this invention, the lifetime management of a bearing can be performed appropriately and the frequency | count of the sudden stop of a stirrer can be reduced.

It is process drawing which shows the high pressure acid leaching method for obtaining a nickel-cobalt mixed sulfide as an example of the high pressure acid leaching method using sulfuric acid. It is a figure which shows schematic structure of the autoclave apparatus used at a leaching process, (a) is the cross-sectional top view which cut the autoclave apparatus horizontally, and showed the internal structure typically, (b) is an autoclave apparatus perpendicularly | vertically. It is the vertical side view which cut | disconnected and showed the internal structure typically, (c) is the vertical front which cut | disconnected the autoclave apparatus perpendicularly | vertically at the position of the AA line of (a), and showed the internal structure typically. FIG. It is a longitudinal cross-sectional view which shows the structure of the bearing unit with which the stirrer of an autoclave apparatus is provided. It is a flowchart which shows the replacement time determination method of the bearing which concerns on embodiment of this invention. It is a figure which shows the relationship between the iron powder density | concentration in grease, and the number of peeling of a bearing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the embodiment of the present invention, description will be made in the following order.
1. 1. High pressure acid leaching method 2. Autoclave device 3. Bearing unit Inventor's knowledge 5. Bearing replacement time determination method 5-1. Acquisition stage 5-2. Measurement stage 5-3. Judgment stage 6. Effects of the embodiment 7. Example 8 Other embodiments

<1. High pressure acid leaching method>
FIG. 1 is a process diagram showing a high pressure acid leaching method for obtaining a nickel / cobalt mixed sulfide as an example of a high pressure acid leaching method using sulfuric acid. This high-pressure acid leaching method includes a pretreatment step S1, a leaching step S2, a solid-liquid separation step S3, a neutralization step S4, a dezincification step S5, a sulfurization step S6, and a detoxification step S7.

  In the pretreatment step S1, the nickel oxide ore is crushed and classified using a pulverization facility and a sieving facility to obtain an ore of 2 mm or less, and a raw slurry having a predetermined slurry concentration containing this ore is prepared. The raw material slurry is supplied to the next leaching step S2.

  In the leaching step S2, the raw material slurry obtained in the pretreatment step S1 is stepped up and stepped in steps by a preheater (temperature raising and pressure raising equipment), and then supplied to the autoclave apparatus. In the autoclave apparatus, sulfuric acid that has been similarly heated and pressurized is added to the raw slurry, and stirred at 220 to 280 ° C. to leach valuable metals. Thereby, since the leaching slurry is obtained, the temperature of the leaching slurry is lowered to a normal temperature and a normal pressure with a flash vessel.

  In the solid-liquid separation step S3, the valuable metal leaching slurry obtained in the leaching step S2 is subjected to solid-liquid separation to obtain a leaching solution (crude nickel sulfate aqueous solution) containing nickel and cobalt as valuable metals and a leaching residue.

  In the neutralization step S4, the leachate obtained in the solid-liquid separation step S3 is neutralized.

  In the zinc removal step S5, hydrogen sulfide gas is added to the leachate neutralized in the neutralization step S4 to precipitate and remove zinc as zinc sulfide.

  In the sulfidation step S6, hydrogen sulfide gas is added to the final zinc removal solution obtained in the dezincification step S5 to obtain a nickel / cobalt composite sulfide and a nickel poor solution.

  In the detoxification process S7, the leaching residue generated in the solid-liquid separation process S3 and the poor liquid generated in the sulfurization process S6 are detoxified.

  Here, in the autoclave apparatus used in the leaching step S2, the ore slurry and sulfuric acid, which are raw material slurries, are respectively stirred by a stirrer in a plurality of compartments, and the slurry is sequentially transferred from the upstream compartment to the downstream compartment. Then, the leaching of valuable metals proceeds. In the high-pressure acid leaching method for obtaining a nickel-cobalt mixed sulfide, a raw material slurry made of ore slurry of nickel oxide ore is heated and pressurized and supplied to an autoclave apparatus.

<2. Autoclave device>
FIG. 2 is a diagram showing a schematic configuration of an autoclave device used in the leaching process, wherein (a) is a cross-sectional plan view schematically showing the internal structure by horizontally cutting the autoclave device, and (b) is an autoclave device. It is the vertical side view which cut | disconnected perpendicularly and showed the internal structure typically, (c) cut | disconnects the autoclave apparatus perpendicularly | vertically at the position of the AA line of (a), and shows the internal structure typically FIG.

  The illustrated autoclave apparatus 100 is used in the leaching step S2 for leaching valuable metals by stirring heated and pressurized raw material slurry and sulfuric acid, and includes a horizontally installed cylindrical autoclave main body 110. . The autoclave body 110 includes a plurality of partition walls 10 (10A to 10F), and the interior of the autoclave body 110 is partitioned by the partition walls 10 into a plurality of compartments 20 (20A to 20G).

  In each compartment 20 (20A to 20G) of the autoclave main body 110, a stirrer 30 (30A to 30G) is installed. The rotational speed of the stirrer 30 is set to 72 rpm, for example.

  Two raw slurry supply pipes 1A and 1B, two sulfuric acid supply pipes 2A and 2B, and a high-pressure steam supply pipe 3 are connected to the most upstream compartment 20A. A sulfuric acid supply pipe 4 is connected to the compartment 20B adjacent to the compartment 20A.

  A safety valve vent pipe 5 is connected to a compartment 20F adjacent to the most downstream compartment 20G. Further, a gas pressure adjusting vent pipe 6, a slurry extraction pipe 7, and a spare pipe 8 are connected to the most downstream compartment 20G.

  A manhole 41 is provided in the most upstream compartment 20A. The manhole 41 is disposed on the floor wall portion in the vicinity of the partition wall 10A and is closed by an opening / closing lid (not shown). Further, a manhole 42 is provided in the downstream compartment 20F, and a manhole 43 is also provided in the most downstream compartment 20G. The manhole 42 is disposed on the floor wall portion in the vicinity of the partition wall 10F and is closed by an opening / closing lid (not shown). The manhole 43 is disposed in a ceiling portion near the partition wall 10F and is closed by an opening / closing lid (not shown).

  Further, the autoclave main body 110 is provided with a liquid passing port 52 (52A to 52F) for slurry transfer.

  In the autoclave apparatus 100 having the above-described configuration, raw material slurry and sulfuric acid are supplied to the most upstream compartment 20A through raw material slurry supply pipes 1A and 1B and sulfuric acid supply pipes 2A and 2B. Further, high-pressure steam is supplied to the compartment 20A through the high-pressure steam supply pipe 3, and sulfuric acid is supplied to the compartment 20B through the sulfuric acid supply pipe 4.

  Thereby, in the autoclave main body 110, the slurry is sequentially transferred from the most upstream compartment 20A toward the most downstream compartment 20B. At this time, between each of the compartments 20 (20A to 20G), slurry is supplied through the liquid passage ports 52 (52A to 52F) provided in the lower part of the partition walls 10 (10A to 10F), while the partition walls 10 ( The slurry is supplied by overflow from the top of 10A-10F). The overflow amount of the slurry is adjusted by the adjusting weir plate 11C and the notch portion 12C shown in FIG.

  Moreover, in each compartment 20 (20A-20G), the stirrer 30 (30A-30G) rotates clockwise, respectively, and the downward flow of a slurry is formed. Thereby, the slurry supplied to each compartment 20 (20A-20G) is stirred by the stirrer 30 (30A-30G). As a result, in the process of sequentially transferring the slurry from the most upstream compartment 20A to the most downstream compartment 20G, the slurry is stirred by the stirrer 30 (30A to 30G), and leaching of valuable metals proceeds.

<3. Bearing unit>
Then, the structure of the bearing unit with which the stirrer 30 of the autoclave apparatus 100 is provided is demonstrated using FIG.

  A bearing unit 33 is attached to the upper end of the rotating shaft 31 of the stirrer 30. The upper end portion of the rotating shaft 31 protrudes above the upper wall 110A of the autoclave main body 110, and the mechanical seal 32 and the bearing unit 33 are attached to the protruding portion. The mechanical seal 32 is provided to maintain the internal pressure of the autoclave main body 110 and has sufficient resistance to high temperature and high pressure in the autoclave main body 110.

  The bearing unit 33 rotatably supports the rotating shaft 31 of the stirrer 30 and holds the load of the stirrer 30. The bearing unit 33 is disposed on the mechanical seal 32. The bearing unit 33 uses, for example, three bearings to hold an axial load acting in the direction of the rotating shaft 31 (axial direction) and a radial load acting in the direction orthogonal to the rotating shaft 31 (radial direction). It is configured.

  Each of the three bearings is configured using a tapered roller bearing. Specifically, for example, it is constituted by a combination of one thrust spherical roller bearing and two spherical roller bearings. In that case, the two self-aligning roller bearings are arranged so as to sandwich one thrust self-aligning roller bearing in the direction of the rotating shaft 31. In addition, the dashed-two dotted line in the figure has shown the gear box base 34 for attaching a gear box. The gear box houses a gear for transmitting a rotational force such as a motor (not shown) to the rotary shaft 31.

<4. Inventor's Knowledge>
As described above, a plurality of stirrers 30 (30A to 30G) are attached to the autoclave apparatus 100, and if one of them fails, the operation of the plant is stopped to repair the stirrer 30. There is a need. For this reason, it is necessary to replace the bearing at an appropriate timing before the stirrer 30 fails.

  The problem that the operation efficiency decreases due to the repair of the stirrer 30 is minimized by, for example, systematically replacing parts including the bearings of the stirrer 30 in accordance with the timing of periodic inspection and maintenance of the plant. can do. However, if the life of the parts cannot be maintained until the timing of inspection and maintenance, it is necessary to suddenly stop the plant due to the life of the bearing before the next inspection and maintenance timing is reached. If the bearings of all the agitators 30 are replaced at the timing of regular inspection and maintenance, sudden plant stoppage can be avoided. However, in that case, since the bearings that can maintain the service life until the next inspection and maintenance timing are also replaced, the parts replacement cost increases. Furthermore, it is not practical to extend the periodic maintenance period in order to avoid an increase in parts replacement costs.

  Further, if the bearing life is determined to be a certain period from the start of use, for example, two years, and a bearing that has reached this period is replaced while the plant is stopped for inspection and maintenance, the number of replacements can be reduced. However, the damaged state of the bearing varies depending on the operation state of each agitator 30. For this reason, the bearing may be damaged before the predetermined period is reached. Therefore, the risk of operation stop cannot be sufficiently suppressed.

  The inventor diligently studied the grease (lubricant) used in the bearing and reached the conclusion that the life of the bearing can be assumed by the concentration of iron powder contained in the grease. And it decided to solve the said subject by analyzing the iron powder density | concentration of the discharge | emission grease obtained by the regular lubrication to a bearing, and judging the replacement time of a bearing. The present invention has been made based on such knowledge of the inventors.

<5. Bearing replacement time judgment method>
FIG. 4 is a flowchart showing a bearing replacement time determination method according to the embodiment of the present invention.
This bearing replacement time determination method includes an acquisition step S11, a measurement step S12, and a determination step S13.

(5-1. Acquisition stage)
In the acquisition step S11, information indicating the relationship between the iron powder concentration in the grease in the bearing and the life of the bearing is acquired. This information is obtained, for example, by preparing a plurality of bearings before and after reaching the end of life, taking out grease from each bearing, and measuring the concentration of iron powder in the grease. The bearing before reaching the end of its life may be a bearing that is normally used by a stirrer. Also, bearings that have reached the end of their service life may be those bearings that have been found to be rotating abnormally with a stirrer and need to be replaced.

  The iron powder concentration (unit: mass%) in the grease can be measured, for example, by a magnetic balance type electromagnetic induction method. As the iron powder concentration in the grease increases, the number of peeling inside the bearing increases (see FIG. 5). This is because the surface of the outer ring, the inner ring, the rolling element, etc. of the bearing is worn with the passage of time of use of the bearing, and the iron powder peeled from the surface is mixed into the grease. It is thought that the iron powder mixed in the grease becomes a foreign substance and further causes peeling. If the iron powder concentration in the grease increases due to the occurrence of peeling, the bearing will be damaged at a certain stage.

  With regard to the life of the bearing, for example, if the occurrence of abnormal rotation due to damage inside the bearing or the like is observed, or if flaking occurs before the occurrence of abnormal rotation, it is determined that the life has been reached. It is possible. As the damage inside the bearing, for example, the outer ring or the cage may be damaged. Flaking is a phenomenon in which the raceway surface of the inner ring or outer ring of the bearing or the rolling surface of the rolling element peels off in a scaly manner. The occurrence of flaking can be confirmed by disassembling the bearing and observing the surfaces of the raceway surface and rolling surface by inspecting the bearing described below.

(Bearing inspection)
The bearing is inspected in the following procedure, for example. First, remove the bearing from the rotating shaft of the stirrer, collect grease for investigation, and then wash the bearing. Generally, light oil or white kerosene is used as the cleaning agent. Cleaning the removed bearing is divided into rough cleaning and finish cleaning. Each cleaning container is provided with a metal mesh raised bottom so that the bearings do not touch the cleaning container directly. During rough cleaning, be careful when rotating the bearings with foreign matter on them, as the rolling surface may be scratched. In rough cleaning oil, use a brush or the like to remove grease and deposits. Finish cleaning is performed carefully while rotating the bearing in the cleaning agent (in oil).

  After finishing cleaning, check the external appearance of the bearing by visual inspection. In the appearance inspection, carefully check for bearing damage and abnormalities such as bearing raceways, rolling surfaces, fitting surfaces, cage wear, increased clearance inside the bearing, and reduced dimensional accuracy. When the bearing to be inspected is a separate type bearing such as a tapered roller bearing, the raceway surfaces of the rolling elements and the outer ring are separately examined.

(5-2. Measurement stage)
In the measurement step S12, the bearing in use in the stirrer is set as a diagnosis target, and the iron powder concentration in the grease in the diagnosis target bearing is measured. At that time, the grease of the bearing to be diagnosed is extracted without removing the bearing from the agitator. Specifically, for example, a grease supply passage and a drainage passage leading to the inside of the bearing are provided, and when new grease is supplied to the bearing through the grease supply passage, old grease discharged to the grease removal passage is collected. To do. Thereby, the grease of the bearing can be replaced with a new one, and the old grease that has been used can be taken out from the bearing. The iron powder concentration in the grease thus extracted is measured by the same method as in the acquisition step S11.

(5-3. Determination stage)
In the determination step S13, the replacement time of the bearing to be diagnosed is determined using the measured value of the iron powder concentration obtained in the measurement step S12 and the information obtained in the acquisition step S11. In this determination, first, based on the information obtained in the previous acquisition step S11, an iron powder concentration threshold value that is a determination criterion for the bearing replacement time is set. The setting step S14 for setting the iron powder concentration threshold may be performed at any timing after the acquisition of the information in the acquisition step S11 and before determining the bearing replacement time in the determination step S13. FIG. 4 illustrates a case where the setting step S14 is performed after the measurement step S12 and before the determination step S13.

(Iron powder concentration threshold setting)
The information acquired in acquisition step S11 is used to set the iron powder concentration threshold. Specifically, "D1" is the maximum iron powder concentration (unit: mass%) in grease measured for bearings before reaching the end of life, and in grease measured for bearings after reaching end of life. Assuming that the minimum value of the iron powder concentration of “D2” is “D2” and the iron powder concentration threshold value that is the determination criterion of the bearing replacement time is “Dth”, the condition of “D1 <Dth <D2” is set.

  As described above, when the iron powder concentration threshold value Dth is set in the setting step S14, in the determination step S13, the measured value Dm of the iron powder concentration obtained in the measurement step S12 is compared with the iron powder concentration threshold value Dth. If the measured value Dm of the iron powder concentration is equal to or greater than the iron powder concentration threshold Dth, it is determined that the bearing to be diagnosed has reached the replacement time in the measurement step S12.

  The measurement step S12 and the determination step S13 are performed at a cycle shorter than a periodic cycle of plant inspection and maintenance performed regularly. For example, when the inspection and maintenance of the plant is performed twice a year, that is, every six months, the measurement step S12 and the determination step S13 are performed at a shorter cycle, preferably a two-month cycle, more preferably a one-month cycle, More preferably, it may be performed in a cycle of 2 weeks. In addition, the bearing replacement operation determined to have reached the replacement period within the inspection and maintenance period (6 months) of the plant is performed the next time according to the difference between the measured value Dm of the iron powder concentration and the iron powder concentration threshold Dth. It may be performed at the timing of inspection and maintenance, or may be performed at the timing before that. Specifically, when the difference between the measured value Dm of the iron powder concentration and the iron powder concentration threshold value Dth is larger than a predetermined value set in advance, it is performed at the next inspection and maintenance timing. What is necessary is just to carry out at the timing before that (for example, the timing which stops operation of a plant for purposes other than inspection maintenance).

<6. Effects of the embodiment>
According to the embodiment of the present invention, one or more effects described below can be obtained.

  In the embodiment of the present invention, the information indicating the relationship between the iron powder concentration in the grease in the bearing and the life of the bearing, and the measured value of the iron powder concentration in the grease measured with the bearing being used in the stirrer as a diagnosis target Is used to determine when to replace the bearing to be diagnosed. Thereby, a bearing replacement | exchange can be performed at the appropriate timing before a bearing reaches lifetime. As a result, the life management of the bearing can be appropriately performed, and the number of sudden stops of the agitator can be reduced.

<7. Example>
First, as the above acquisition step S11, for the five samples A, B, C, F, and G, the usage period of the bearing, the transition of the iron powder concentration in the grease, and the damage state of the bearing were confirmed. Results such as 1 and Table 2 were obtained. In addition, the information shown in Table 1 and Table 2 is equivalent to the information which shows the relationship between the iron powder density | concentration in the grease in a bearing, and the lifetime of the bearing. For the measurement of the iron powder concentration in the grease, a grease iron powder concentration meter (SDM-72) manufactured by Shin Cosmos Electric Co., Ltd. was used.

  In the bearing of sample A, the iron powder concentration in the grease was 0.025% by mass immediately after replacement, but when the service period was 6 months, it increased to 0.081% by mass, and in 12 months it was 0.300% by mass. It became. When the bearing that had been used for 12 months was disassembled and the raceway surface and the surface of the rolling element were observed, the damage level developed from peeling to flaking. For this reason, the bearing was replaced with a new one.

  In the bearing of Sample B, the concentration of iron powder in the grease was 0.010% by mass immediately after replacement, and it was 0.008% by mass in both the 6 months and 12 months. In the bearing of Sample C, the concentration of iron powder in the grease was 0.004% by mass immediately after the replacement, and it was 0.007% by mass in both the service period of 6 months and 12 months. That is, in the bearings of Samples B and C, the iron powder concentration in the grease was 0.01% or less when the service period was 12 months. Further, when the bearings of Samples B and C were disassembled and the raceway surface and the surface of the rolling element were observed, damage such as peeling was not observed.

  On the other hand, the outer ring / retainer of the bearing of Sample F was damaged when the service period was 7 months. For this reason, the plant operation was stopped and replaced with a new bearing. At that time, the iron powder concentration in the grease in the bearing damaged by use was measured and found to be 0.512% by mass.

  As for the bearing of sample G, the outer ring / retainer was damaged when the service period was 9 months. For this reason, the plant operation was stopped and replaced with a new bearing. At that time, the iron powder concentration in the grease in the bearing damaged by use was measured and found to be 0.600% by mass.

  As described above, from the results of Tables 1 and 2, the iron powder concentration threshold value, which is a criterion for determining the bearing replacement time, is set to Dth = 0.10% by mass with respect to the iron powder concentration in the grease. Under this setting condition, when the measured value Dm of the iron powder concentration obtained in the measurement step S12 is 0.10% by mass or more, it is determined that the bearing to be diagnosed has reached the replacement time.

  In the past, sudden plant shutdowns due to bearing damage occurred once to four times a year. On the other hand, based on the bearing replacement time determination method according to this embodiment, the iron powder concentration threshold is set to Dth = 0.10% by mass, and the bearing has an iron powder concentration of 0.10% by mass or more. As a result of the replacement, the suspension of operation due to bearing damage no longer occurred.

  In the present embodiment, as a preferable example, the iron powder concentration threshold is set to Dth = 0.10% by mass, and based on this setting, the iron powder concentration in the grease is 0.10% by mass or more. Although the bearing was the subject of replacement, as another preferred example, the iron powder concentration threshold value, which is a criterion for determining the bearing replacement time, is 0.05 mass% and 0.20 mass depending on the urgency of the bearing replacement. % May be set in two stages. In this case, bearings whose iron powder concentration in the grease is 0.05% by mass or more are subject to replacement, but with regard to the replacement period, bearings whose iron powder concentration is 0.20% by mass or more are more iron. The replacement time may be determined so that it is replaced earlier than a bearing having a low powder concentration. In addition, for example, a bearing in which the concentration of iron powder in grease is more than 0.05 mass% and less than 0.1 mass% and a bearing in which 0.05 mass% or less may be used may change the subsequent measurement cycle of the iron powder concentration. . Specifically, when the measurement cycle of the latter bearing is a specified cycle, the measurement cycle of the former bearing may be changed to be shorter than the specified cycle.

<8. Other embodiments>
Subsequently, a preferred embodiment in the case where the above-described bearing replacement time determination method is applied to an autoclave apparatus used in a high-pressure acid leaching method will be described.

  First, as shown in FIG. 2, in the autoclave apparatus 100 used in the high pressure acid leaching method, the interior of the autoclave main body 110 is divided into a plurality of compartments 20 (20A to 20G), and each compartment 20 (20A to 20A to 20A) is divided. A stirrer 30 (30A to 30G) is provided every 20G). For this reason, there are a plurality of agitators 30 (30A to 30G) whose life of the bearing should be managed. In such a case, the iron powder concentration threshold value, which is a criterion for determining the bearing replacement time, may be set to the same value for the plurality of agitators 30 (30A to 30G), but more preferably described below. Based on the bearing replacement time determination method including the acquisition step S11, the measurement step S12, the determination step S13, and the determination step S14, it is preferable to manage the life of the bearing for each of the agitators 30 (30A to 30G).

  First, in acquisition step S11, information indicating the relationship between the iron powder concentration in grease in the bearing and the life of the bearing is acquired for each stirrer 30 (30A to 30G). Further, in the measurement step S12, a bearing in use in at least one of the plurality of stirrers 30 (30A to 30G) is a diagnosis target, and the iron powder concentration in the grease in the diagnosis target bearing is measured.

  On the other hand, in the setting step S14, an iron powder concentration threshold is set for each stirrer 30 (30A to 30G) based on the information obtained in the obtaining step S11. At this time, you may set an iron powder density | concentration threshold value to a different value for every stirrer 30 (30A-30G). Further, the stirrers 30 (30A to 30G) may be grouped from the upstream side toward the downstream side, and the iron powder concentration threshold may be set to a different value for each group. Further, the iron powder concentration threshold value may be set to a larger value or a smaller value in the stirrer 30 positioned relatively upstream than in the stirrer 30 positioned downstream.

  In the determination step S13, based on the measured value of the iron powder concentration obtained in the measurement step S12 and the iron powder concentration threshold set corresponding to the stirrer having the bearing to be diagnosed, the replacement timing of the bearing to be diagnosed is determined. Determine.

  Thus, the iron powder concentration threshold is individually set for each of the stirrers 30 (30A to 30G), and the replacement time of the bearing is determined in accordance with the threshold value, so that all of the stirrers 30 (30A to 30G) are identical. Compared to the case where the iron powder concentration threshold is applied, the bearing can be replaced at a more appropriate timing. The reason is as follows.

  In the autoclave body 110 of the autoclave apparatus 100, the slurry is sequentially transferred from the most upstream compartment 20A toward the most downstream compartment 20G. At that time, the state of the agitator 30 (30A to 30G) provided in each of the compartments 20A to 20G and the state of the slurry existing in each of the compartments 20A to 20G are not necessarily the same. Specifically, for example, even if the type of the stirrer 30 used is the same, the mounting state and mounting accuracy of the stirrer 30 may be different. Further, the slurry moves downstream while being stirred in each of the compartments 20A to 20G, and leaching of valuable metals progresses during the movement, so that the properties (for example, viscosity) may change. In such a case, in each stirrer 30, the magnitude and direction of the load acting on the bearing that supports the rotating shaft 31 may change.

  The magnitude and direction of the load acting on the bearing affects the occurrence of peeling, the rate of increase in the number of peelings, and consequently the life of the bearing. For this reason, if an iron powder density | concentration threshold value is individually set for every stirrer 30 (30A-30G) and it determines the replacement | exchange time of a bearing according to this setting, it will be more suitable for each stirrer 30 (30A-30G). The bearings can be replaced at the right timing.

  Further, a plurality of (three in this embodiment) bearings of different types are incorporated in the bearing unit 33 attached to the rotating shaft 31 of the stirrer 30. Thus, when one agitator 30 is provided with a plurality of bearings of different types, an iron powder concentration threshold is set for each bearing of different types in the setting step S14, and the determination step S13. Replaces the bearing at an appropriate timing according to the type of bearing by determining the replacement timing of the bearing to be diagnosed using the iron powder concentration threshold set corresponding to the type of bearing to be diagnosed. Can be performed.

20 (20A to 20G)) ... compartment 30 (30A to 30G)) ... stirrer 31 ... rotating shaft 33 ... bearing unit 100 ... autoclave device 110 ... autoclave body

Claims (5)

High pressure that stirs heated and pressurized raw material slurry and sulfuric acid with a stirrer in each of the plurality of compartments, and advances the leaching of valuable metals by sequentially transferring the slurry from the upstream compartment to the downstream compartment A bearing replacement time determination method applied to an autoclave device used in an acid leaching method,
The autoclave device includes a plurality of stirrers corresponding to the plurality of compartments, and each stirrer has a bearing,
An acquisition step of acquiring information indicating the relationship between the iron powder concentration in the grease in the bearing and the life of the bearing for each of the agitators,
A measurement step of measuring a bearing in use in at least one of the plurality of agitators as a diagnosis target, and measuring a concentration of iron powder in the grease in the diagnosis target bearing;
Based on the information obtained in the acquisition stage, the iron powder concentration threshold that is a criterion for determining the bearing replacement time, for each of the agitators, or for each group in which the agitators are grouped from the upstream side toward the downstream side, A setting stage to set different values ;
Based on the measured value of the iron powder concentration obtained in the measurement step and the iron powder concentration threshold set corresponding to the stirrer having the diagnosis target bearing, the replacement time of the diagnosis target bearing A determination stage for determining
To determine when to replace bearings. The iron powder concentration threshold value is set to a value that is larger for the stirrer positioned relatively upstream than the stirrer positioned downstream.
The bearing replacement time determination method according to claim 1. The iron powder concentration threshold is set to a value smaller in the stirrer located on the relatively upstream side than the stirrer located on the downstream side.
The bearing replacement time determination method according to claim 1. The time to replace the bearing to be diagnosed is determined according to the occurrence of flaking before rotation abnormality is reached.
The bearing replacement time determination method according to any one of claims 1 to 3. The autoclave apparatus has a plurality of bearings of different types in one agitator,
In the setting step, the iron powder concentration threshold is set for each of the different types of bearings,
Wherein in the determination step, with the diagnosis target and the iron powder density threshold that is set to correspond to the type of bearing, in any one of the four replacement time of the diagnosis target bearing from judges claim 1 The method for determining the bearing replacement time described.