JP5834960B2 - Thickener device and operation management method in ore slurry manufacturing process - Google Patents

Description

  The present invention relates to a thickener device in an ore slurry manufacturing process and an operation management method thereof, and more particularly to a thickener management method in a nickel oxide ore slurry manufacturing process sent to a high-temperature pressurized sulfuric acid leaching process.

  Conventionally, a thickener is generally used as a means for adding an additive to a slurry formed from ore containing a non-ferrous metal and then collecting the slurry by sedimentation and concentration. The thickener structure is composed of a feed well to which slurry and additives are supplied, and a sedimentation concentration unit that concentrates the sedimented slurry by slow rotation of a rake connected to the drive unit by a rotating shaft. Is used. Here, in the feed well, for example, a floc is formed using an aggregating agent as an additive in order to improve the sedimentation property of the slurry, or a neutralizing agent is used as an additive to neutralize the slurry. To promote precipitation.

  In addition, as a measuring method and apparatus for thickener concentrated slurry interface used to manage thickeners during the sedimentation and separation of slurries such as red mud, lime mud and ore mud that are by-produced by the buyer method of producing alumina from bauxite, In order to measure the position of the interface between the supernatant layer and the dense layer precipitated and concentrated in a safe and accurate manner without human intervention, a measuring method and apparatus for the thickener concentrated slurry interface using an ultrasonic densitometer are provided. It has been proposed (see, for example, Patent Document 1).

  In addition, as a hydrometallurgical method for recovering valuable metals such as nickel and cobalt from nickel oxide ores with low nickel content typified by limonite ore, etc., high pressure acid leaching (HPAL) using sulfuric acid (HPAL (High Pressure Acid Leaching)) The sulfuric acid leaching method is used.

  In the high pressure acid leaching method for obtaining the nickel-cobalt mixed sulfide, for example, as shown in FIG. 6, the pretreatment step (1), the leaching step (2), the solid-liquid separation step (3), It includes a summing step (4), a dezincing step (5), a sulfiding step (6), and a detoxifying step (7).

  In the pretreatment step (1), the nickel oxide ore is crushed and classified into a slurry.

  In the leaching step (2), sulfuric acid is added to the slurry obtained in the pretreatment step (1), and the mixture is stirred at 220 to 280 ° C. to obtain a high-temperature pressure acid leaching to obtain a leaching slurry.

  In the solid-liquid separation step (3), the leaching slurry obtained in the leaching step (2) is subjected to solid-liquid separation to obtain a leachate containing nickel and cobalt (hereinafter referred to as “crude nickel sulfate aqueous solution”) and the leaching residue. obtain.

  In the neutralization step (4), the crude nickel sulfate aqueous solution obtained in the solid-liquid separation step (3) is neutralized.

  In the zinc removal step (5), hydrogen sulfide gas is added to the crude nickel sulfate aqueous solution neutralized in the neutralization step (4) to precipitate and remove zinc as zinc sulfide.

  In the sulfidation step (6), hydrogen sulfide gas is added to the final zinc removal solution obtained in the dezincification step (5) to obtain a nickel / cobalt composite sulfide and a nickel poor solution. In the detoxification step (7), the leaching residue generated in the solid-liquid separation step (3) and the nickel poor solution generated in the sulfidation step (6) are detoxified (see, for example, Patent Document 2).

  Here, in the wet smelting method based on high-temperature pressurized sulfuric acid leaching to recover nickel from low-grade nickel oxide ore, the ore sent to the high-temperature pressurized sulfuric acid leaching step is less than a predetermined size using a wet sieve And is slurried. In addition, ore slurry usually sent to the high-temperature pressurized sulfuric acid leaching process has several types so that the acid consumption in the high-temperature pressurized sulfuric acid leaching process, the nickel concentration of the resulting leachate, and other impurity concentrations are at a predetermined ratio. Made by blending nickel oxide ore.

  Since the solid% (solid content concentration (weight%)) of the ore slurry obtained at this time is as low as 10 to 20%, if it is sent to the high-temperature pressure sulfuric acid leaching process as it is, the nickel of the leachate after the high-temperature pressure leaching process There is a problem that the concentration is low and the amount of liquid for treating the same amount of nickel increases and nickel cannot be recovered efficiently. Therefore, the ore slurry sent to the high-temperature pressurized sulfuric acid leaching process increases the Solid% using a thickener to increase the nickel passage amount per unit time to the high-temperature pressurized sulfuric acid leaching process to 40-45%. Adjusted.

  That is, an ore slurry having a low Solid% is sent to a high-temperature pressurized sulfuric acid leaching process after increasing the Solid% of the ore slurry using a thickener.

JP 2000-055714 A JP-A-2005-350766

  By the way, in the hydrometallurgical method based on high-temperature pressurized sulfuric acid leaching for recovering nickel from low-grade nickel oxide ore, the Solid% of the slurry obtained from thickener has different settling behavior depending on the ore type, so the kind of blended ore, Depends on blend ratio and type, amount, etc. of flocculant used.

  However, since the ore has different sedimentation behavior inside the thickener depending on the ore type, in order to obtain the desired Solid%, the addition of the flocculant based on past data and the rule of thumb of the operator according to the blended ore type and its ratio In addition, it is necessary to check the agglomeration state by an operator and maintain an optimum thickener bed level using a bed level (thickness of the completely settled slurry layer) measuring jig.

  Conventionally, the amount of flocculant added was changed according to past data and the worker's empirical rule according to the blended ore type and ratio, and in addition, the bed level measuring jig was used to check the state of aggregation and sedimentation by the worker. The target Solid% was obtained by checking and managing the optimum thickener bed level.

  Therefore, when changing the ore type, stable management of the thickener becomes difficult, often causing deterioration of cohesiveness and bed level fluctuation due to lack of coagulant, especially when a slurry floating layer is formed at the bottom of the thickener due to deterioration of cohesiveness. The response is delayed because it is difficult to determine the aggregation state by human sensitivity measurement, and if the measurement frequency is low, the sedimentation state is improved or deteriorated, and time series information cannot be obtained. As a result, there were many troubles that the slurry did not settle sufficiently and overflowed from the thickener. In particular, the sedimentation property of the slurry deteriorated due to the deterioration of the cohesiveness, and it was difficult to judge when a floating layer was formed under the thickener.

  Therefore, the present invention has been devised in view of the above-described conventional situation, and the purpose of the present invention is to provide nickel oxide ore in a nickel hydrometallurgical smelting method using a high-temperature pressure sulfuric acid leaching method from nickel oxide ore. In the slurry manufacturing process, the target Solid% ore slurry can be obtained without being affected by the ore type and blend ratio, and the high Solid% ore slurry can always be sent to the high temperature pressure leaching process. Another object of the present invention is to provide a thickener device and an operation management method thereof in an ore slurry manufacturing process that can contribute to a reduction in the use amount of a flocculant.

  Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the description of embodiments described below.

  In order to achieve the above object, the inventors of the present invention as a result of earnest research on the management method of thickener operation, in the nickel oxide ore slurry manufacturing process sent to the high-temperature pressurized sulfuric acid leaching process, the liquid level by the ultrasonic level measuring device The present invention was completed by finding a method for obtaining a target solid% ore slurry regardless of different ore ratios and ore types by applying level measurement results to image management as image data.

That is, the present invention is a thickener device used in a nickel oxide ore slurry manufacturing process that is sent to a high-temperature pressurized sulfuric acid leaching process, wherein the supplied ore slurry is allowed to settle, so that A thickener in which a sedimentation concentration part is formed, a feed well for mixing the flocculant and dilution water into the ore slurry, and an ultrasonic wave are installed to be positioned above the supernatant liquid part in the thickener, and The ultrasonic transducer that receives the reflected wave at the interface between the liquid surface of the supernatant liquid part and the sedimentation aggregated layer of the sedimentation concentration part measures the time from when the ultrasonic wave is transmitted until the reflected wave is received, and based on that time. Based on the measurement result by the ultrasonic level measuring device and the ultrasonic level measuring device that calculates the distance to the interface by the measurement processing unit, Serial slurry layer to be detected as an ultrasonic noise regarded as floating layer on the way to be aggregated state from sedimentation, and quantitatively evaluated over time the thickness of the thickener inside the floating layer, the When mixing the ore slurry, the flocculant, and the dilution water , in order to optimize the addition amount of the flocculant, the reflection state of the ultrasonic wave according to the slurry settling condition inside the thickener is continuously changed. And a monitoring device that displays a screen.

The present invention also relates to an operation management method for a thickener device used in a nickel oxide ore slurry manufacturing process to be sent to a high-temperature pressurized sulfuric acid leaching process, wherein the upper supernatant liquid is settled by settling the supplied ore slurry. It is installed so that it is located at the upper part of the supernatant liquid part in the thickener where the part and lower sediment concentration part is formed, transmits ultrasonic waves, and the liquid level of the supernatant liquid part and the sedimentation aggregation layer of the sediment concentration part The ultrasonic transducer that receives the reflected wave from the interface measures the time until the ultrasonic wave is transmitted and the reflected wave is received, the distance to the interface is calculated by the measurement processing unit based on the time, and the measurement processing is performed. Based on the calculation result by the unit, the reflection state of the ultrasonic wave according to the slurry settling state inside the thickener is continuously displayed on the screen by the monitoring device, Based on the screen display by the monitoring device, the layer detected as the ultrasonic noise is regarded as a floating layer in the middle of the slurry changing from the sedimentation state to the aggregation state, and the thickness of the floating layer inside the thickener is sometimes series is quantitatively evaluated, the ore slurry, the coagulant, and when mixing the dilution water, characterized by optimizing the amount of the coagulant.

  In the thickening process in the thickener of the ore slurry manufacturing process, instead of confirming the slurry sedimentation state inside the thickener using a measurement jig by a conventional worker, in the present invention, ultrasonic level measurement that can be continuously monitored By using the equipment, it is possible to obtain the sedimentation state and aggregation state of the slurry continuously and quantitatively, accurately grasp the aggregation state inside the thickener, adjust the excess and deficiency of the flocculant, and before the deterioration progresses In addition, by adjusting the supply amount to the thickener or the extraction amount from the thickener and adjusting the bet level, it is possible to maintain the target Solid% and prevent a slurry overflow trouble.

  That is, according to the present invention, in the ore slurry manufacturing process, it becomes possible to obtain the target Solid% ore slurry without being affected by the ore type and blend ratio, and the high Solid% ore slurry is always leached at a high temperature under high pressure. Can be sent to the process. Moreover, it can also contribute to reduction of the usage-amount of a flocculant.

It is a typical longitudinal section showing the composition of the thickener device to which the present invention is applied. It is a figure which shows an example of the image data obtained as a measurement result by the ultrasonic level apparatus with which the said thickener apparatus is equipped. It is a figure which shows an example of the image data obtained as a measurement result by the ultrasonic level apparatus with which the said thickener apparatus is equipped. It is a figure which shows an example of the image data obtained as a measurement result by the ultrasonic level apparatus with which the said thickener apparatus is equipped. It is a figure which shows an example of the image data obtained as a measurement result by the ultrasonic level apparatus with which the said thickener apparatus is equipped. It is a figure which shows typically the process of the high pressure acid leaching method for obtaining nickel * cobalt mixed sulfide.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention is applied to, for example, a thickener device 100 configured as shown in FIG.

  This thickener device 100 is used in a nickel oxide ore slurry manufacturing process that is sent to a high-temperature pressurized sulfuric acid leaching process, and is designed so that an upper supernatant liquid portion and a lower sedimentation concentration portion are formed in a steady state. A thickener 10, and an ultrasonic level measuring device 20 and a monitoring device 30 for monitoring the reflected state of the ultrasonic wave in order to continuously and quantitatively obtain the settling state and agglomeration state of the slurry in the thickener 10. Prepare.

  The thickener 10 includes a thickener body 3 including a cylindrical outer frame 1 and a conical bottom portion 2 that gradually decreases toward the center. The thickener body 3 has a slurry recovery port 4 formed at the center of the conical bottom 2. In addition, a rake 5 is disposed inside the thickener 10 along the inner surface of the conical bottom 2, and a cylindrical feed well 6 centering on the rotating shaft 5 </ b> A of the rake 5 is provided in the thickener 10. It is provided so that it may be located in the upper part of the supernatant liquid part in 10.

  The feed well 6 is fixed to a lid 7 provided on the upper part of the thickener 10. The feed well 6 is connected to the upper position of the feed well 6 with a slurry supply pipe 11 for feeding slurry for sedimentation and concentration, and an additive supply pipe 12 for feeding an additive such as a flocculant. In addition, a dilution water inlet 13 is provided. Further, a dispersion cone 14 for discharging the slurry from the feed well 6 is provided at a lower position of the feed well 6.

  In the thickener 10, the ore slurry, the flocculant, and the dilution water that are subjected to sedimentation concentration are mixed in the feed well 6 and supplied from the feed well 6 into the thickener 10. The ore slurry supplied into the thickener 10 settles and aggregates in a mixed state with a flocculant and dilution water, thereby forming an upper supernatant liquid portion and a lower sedimentation concentration portion. The slurry is recovered as a slurry having a desired concentration from the slurry recovery port 4 provided at the lowermost part. The rake 5 is slowly rotated by a driving unit (not shown) connected to the rotating shaft 5A, so that the slurry is allowed to settle and concentrate in the sedimentation concentration unit to ensure a uniform deposition state.

  The ultrasonic level measuring apparatus 20 transmits an ultrasonic wave and receives the reflected wave. The ultrasonic transducer 21 measures the time until the ultrasonic transducer 21 transmits the ultrasonic wave and receives the reflected wave. The ultrasonic transducer 21 is arranged so as to be positioned above the supernatant liquid portion in the thickener 10. The measurement processing unit 22 calculates the distance to the object based on the time. A commercially available ultrasonic level meter can be used for the ultrasonic level measuring apparatus 20. The monitoring device 30 is connected to the measurement processing unit 22 of the ultrasonic level measurement device 20, and the measurement processing unit 22 is used to monitor the reflection state of the ultrasonic waves by the ultrasonic level measurement device 20. Display the calculation result by.

  In the thickener device 100, the object to be measured by the ultrasonic level measuring device 20 is an interface between the liquid surface of the supernatant liquid portion and the sedimentation aggregated layer of the sediment concentration portion, and the monitoring device 30 performs the measurement process. By displaying the calculation result by the unit 22, that is, the measurement result by the ultrasonic level measuring device 20 on the screen, the interface level between the sedimentation aggregated layer and the liquid surface is continuously grasped, and at the same time, the layer detected as ultrasonic noise is detected. By considering the slurry as a layer that is in a floating state in the middle from the settled state to the agglomerated state, a quantitative evaluation of the thickness of the floating state layer in the middle of the aggregation can be performed.

  Here, the ore has different thickening behavior depending on the ore type, and in particular, there is a strong correlation between the Si grade and the thickening behavior in the ore slurry. As the Si grade increases, the sedimentation deteriorates and the Solid% decreases. Tend to. However, in order to control nickel in the ore slurry, it may be necessary to treat ore with high Si grade, and when the ore blend is changed and the Si grade fluctuates, especially when the Si grade rises, Adjustment is not in time, and the slurry is likely to float on the upper part of the sedimentation layer of the thickener 10.

  In the thickener device 100, the measurement result of the ultrasonic level measuring device 20 is displayed on the screen of the monitoring device 30, whereby the suspended state of the slurry can be grasped.

  An example of image data obtained as a result of measurement by the ultrasonic level measuring apparatus 20 is shown in FIG. 2 (a color drawing is submitted as a reference diagram).

  The range A (red portion) in FIG. 2 means that the amount of reflection from the ultrasonic wave emitted from the transducer 21 is large, and the slurry is completely settled in the thickener 10 below this portion. It is the range of the solid part (slurry sediment layer). In other words, the range of the red portion A where the amount of reflected ultrasonic waves is large can be regarded as a floating layer in the middle of the slurry from the settling state to the agglomerated state at the upper part of the settling layer. By evaluating in series, it is possible to manage the sedimentation state, and hence Solid%.

  In addition, various image data obtained as a result of measurement by the ultrasonic level measurement apparatus 20, the range of A, and Solid% at that time are shown in FIGS. 3 to 5 (color drawings are submitted as reference diagrams).

  As shown in FIG. 3, the lower the range of A, the better the settling state and the higher Solid%. As shown in FIG. 4, when A becomes larger, the settling property deteriorates and the Solid% decreases. In addition, if it is allowed to stand for a long time without adjusting the addition amount of the flocculant in the state of FIG. 4, as shown in FIG. 5B, the interface with the sedimentation layer starts to rise. The slurry overflows from the upper part of the thickener, and the Solid% of the slurry pulled out from the bottom part of the thickener decreases rapidly.

  In the thickener device 100, in consideration of these phenomena, the state shown in FIG. 3 (30 cm or less as a slurry floating layer) is continuously monitored and maintained in operation management, and when the range of A is expanded, the flocculant By increasing the added amount of the slurry, it is possible to suppress slurry overflow and stably obtain a slurry with a high Solid%.

  In the thickener device 100, the ultrasonic level measuring device 20 and the monitoring device 30 capable of monitoring the reflected state of the ultrasonic waves are provided, so that the interface level between the sedimentation aggregate layer and the liquid surface in the thickener 10 can be continuously grasped. By considering the layer detected as ultrasonic noise as a layer that is in a suspended state while the slurry is in the aggregated state from the settled state, the thickness of the suspended layer in the middle of the aggregation can be quantitatively evaluated, Accurately grasp the agglomeration state inside the thickener 10, adjust the excess or deficiency of the flocculant and adjust the supply amount to the thickener 10 or the extraction amount from the thickener 10 before the deterioration progresses to adjust the bet level. It is possible to maintain the target Solid% and prevent slurry overflow troubles in advance. That.

  Conventionally, a sample extracted from the lower part of the thickener is analyzed periodically, and the solid% is evaluated as a representative value of the entire thickener to grasp the internal aggregation state. Since the sedimentation property can be judged when the slurry thus obtained reaches the upper part of the sedimentation layer, it is possible to judge the increase / decrease of the flocculant without causing a time lag. Therefore, excessive addition of the flocculant can be prevented, and the amount of flocculant added can be optimized.

  That is, in the thickener device 100, in the nickel oxide ore slurry manufacturing process to be sent to the high-temperature pressurized sulfuric acid leaching process, the supplied ore slurry is allowed to settle to form an upper supernatant liquid part and a lower sedimentation concentration part. The ultrasonic wave is installed so as to be positioned above the supernatant liquid portion in the thickener 10, transmits ultrasonic waves, and receives reflected waves from the interface between the liquid surface of the supernatant liquid part and the sedimentation aggregate layer of the sedimentation concentration part. The time until the transducer 21 transmits the ultrasonic wave and receives the reflected wave is measured, the distance to the interface is calculated by the measurement processing unit 22 based on the time, and based on the calculation result by the measurement processing unit 22. Then, the reflection state of the ultrasonic wave corresponding to the slurry settling condition inside the thickener 10 is continuously displayed on the screen by the monitoring device 30, and the upper Based on the screen display by the monitoring device 30, and quantitatively evaluated chronologically slurry settling of internal the thickener 10, operations are managed.

  Further, in the thickener device 100, based on the screen display by the monitoring device 30, the slurry of the layer detected as the ultrasonic noise by the ultrasonic level measuring device 20 is changed from the settled state to the aggregated state. Operation is managed as a floating layer in the middle.

  In the thickener device 100, the thickness of the floating layer in the thickener 10 is quantitatively evaluated, and the amount of the flocculant added to the ore slurry in the thickener 10 is optimized.

  Table 1 below shows the amount (g) of flocculant used per ton of ore before and after the adoption of such an operation management method (flocculating agent basic unit). The measurement results before the adoption of the operation management method were 26 times, and the measurement results after the same adoption were 52 times.

  From Table 1, it can be seen that the amount of the flocculant added to obtain approximately the same Solid% can be reduced after the operation management method is adopted compared to before the adoption. In addition, variation in the amount of the flocculant used can be reduced, and it can be said that the operation management method contributes to the reduction of the amount of flocculant used.

DESCRIPTION OF SYMBOLS 1 Cylindrical outer frame, 2 bottom part, 3 thickener main body, 4 slurry collection port, 5 rakes, 5A rotating shaft, 6 feed well, 7 lid, 10 thickener, 11 slurry supply pipe,
12 Additive supply pipe, 13 Dilution water inlet, 14 Dispersion cone, 20 Ultrasonic level measuring device, 21 Ultrasonic transducer, 22 Measurement processing unit, 30 Monitoring device, 100 Thickener device

Claims (2)

A thickener device used in a slurry manufacturing process of nickel oxide ore to be sent to a high-temperature pressurized sulfuric acid leaching process,
A thickener in which an upper supernatant liquid part and a lower sedimentation concentration part are formed by settling the supplied ore slurry,
A feed well for mixing the flocculant and dilution water into the ore slurry;
An ultrasonic transducer that is installed so as to be positioned above the supernatant liquid portion in the thickener, transmits ultrasonic waves, and receives reflected waves from the interface between the liquid surface of the supernatant liquid portion and the sedimentation aggregate layer of the sedimentation concentration portion. Measuring the time from transmitting an ultrasonic wave to receiving a reflected wave, and calculating the distance to the interface by the measurement processing unit based on the time,
Based on the measurement result by the ultrasonic type level measuring device, the layer detected as the ultrasonic noise is regarded as a floating state layer in the middle of the slurry changing from the settled state to the aggregated state, and the floating state layer inside the thickener In order to optimize the amount of the flocculant added when the ore slurry, the flocculant, and the dilution water are mixed , the thickness of the slurry is settled inside the thickener. A monitoring device that continuously displays the reflection state of the ultrasonic wave according to the situation on the screen;
A thickener device comprising: An operation management method for a thickener device used in a slurry manufacturing process of nickel oxide ore to be sent to a high-temperature pressurized sulfuric acid leaching process,
By setting the supplied ore slurry, the upper supernatant liquid part and the lower sediment concentration part are formed so as to be positioned above the supernatant liquid part in the thickener, transmitting ultrasonic waves, The ultrasonic transducer that receives the reflected wave from the interface between the liquid surface of the liquid part and the sedimentation aggregation layer of the sedimentation concentration part measures the time until the ultrasonic wave is transmitted and the reflected wave is received. The distance to the interface is calculated by the measurement processor,
Based on the calculation result by the measurement processing unit, the reflection state of the ultrasonic wave according to the slurry settling state inside the thickener is continuously displayed on a screen by a monitoring device,
Based on the screen display by the monitoring device, the layer detected as the ultrasonic noise is regarded as a floating layer in the middle of the slurry changing from a settling state to an aggregated state, and the thickness of the floating layer inside the thickener is determined. An operation management method for a thickener device characterized in that the amount of the flocculant is optimized when the ore slurry, the flocculant, and the dilution water are mixed quantitatively evaluated in a time series.