JP5360243B2 - Thickener device in ore slurry manufacturing process and method for controlling solid component ratio - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a thickener device in an ore slurry manufacturing process and a solid component ratio control method thereof, and in particular, a high-temperature pressurized sulfuric acid leaching process in a hydrometallurgical process based on high-temperature pressurized sulfuric acid leaching to recover nickel from low-grade nickel oxide ore. The present invention relates to a method for controlling the solid component ratio in a slurry manufacturing process of nickel oxide ore to be sent to the factory.

  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. As a structure of the thickener, a thickener main body to which slurry and additives are supplied has a type including a sedimentation concentration unit that concentrates the sedimented slurry by slow rotation of a rake connected by a drive unit and a rotation shaft. It is used. Here, in the thickener, for example, flocs are formed using an aggregating agent as an additive in order to improve the sedimentation property of the slurry, or precipitation is performed using a neutralizing agent as an additive in order to neutralize the slurry. The generation is promoted.

  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. 5, the pretreatment step (1), the leaching step (2), the solid-liquid separation step (3), The sum process (4), the dezincification process (5), the sulfurization process (6), and the detoxification process (7) are included (for example, refer patent document 1).

  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 sulfurization step (6) are detoxified.

  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% of the ore slurry obtained at this point is as low as 10 to 20%, the nickel concentration of the leachate after the high temperature pressurization leaching process is low when it is sent to the high temperature pressurization sulfuric acid leaching process. As a result, the amount of liquid to be increased increases and nickel cannot be recovered efficiently. Therefore, the ore slurry sent to the high-temperature pressurized sulfuric acid leaching process increases the Solid% of the ore slurry using a thickener in order to increase the amount of nickel passing through the high-temperature pressurized sulfuric acid leaching process per unit time. To the high-temperature pressurized sulfuric acid leaching process. Here, Solid% of the ore slurry indicates the weight percentage of the solid content (ore) in the ore slurry, that is, the solid component ratio.

JP-A-2005-350766

  As described above, in the hydrometallurgical method based on high-temperature pressurized sulfuric acid leaching to recover nickel from low-grade nickel oxide ore, the ore slurry sent to the high-temperature pressurized sulfuric acid leaching process is unit time to the high-temperature pressurized sulfuric acid leaching process. In order to increase the amount of nickel per pass, the thickener is used to increase the Solid% of the ore slurry and then sent to the high-temperature pressurized sulfuric acid leaching process, but if the Solid% is too high, the viscosity of the slurry increases, Since the problem that the liquid feeding becomes difficult due to the rate limiting of the pump capacity and the problem of the piping clogging occur, the Solid% of the ore slurry is preferably 36 to 45%, preferably 39 to 42%.

  However, since the ore has different thickening behavior depending on the ore type, the Solid% of the slurry obtained from thickener is the blended ore type, blend ratio, type and amount of flocculant used for thickening, and shape and size of thickener. Depends on etc.

  Therefore, when there is one kind of thickener used for thickening, there is a problem that Solid% varies depending on the kind of blended ore, blend ratio, and the like.

  Conventionally, the variation of Solid% was dealt with by changing the amount of flocculant added according to the blended ore type and the ratio thereof, so that the desired predetermined Solid% ore slurry can be stably obtained. Thickening operation management was difficult even for skilled workers.

  Therefore, the present invention has been devised in view of the conventional situation as described above, and the purpose thereof is nickel in a hydrometallurgical method based on high-temperature pressure sulfuric acid leaching for recovering nickel from low-grade nickel oxide ore. Thickener equipment in the ore slurry manufacturing process and its solid component ratio that can send the target Solid% ore slurry to the high temperature pressure leaching process without being affected by the ore type and blend ratio in the oxide ore slurry manufacturing process It is to provide a control method.

  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 present inventors have conducted extensive research on the management method of thickener operation, and as a result, in addition to the conventional one kind of thickener, in the nickel oxide ore slurry manufacturing process sent to the high-temperature pressurized sulfuric acid leaching process. Then, using a thickener having a thickening effect larger than that of the conventional thickener, the ore slurry having a predetermined solid component ratio (Solid%) in each thickener is mixed at a predetermined ratio, thereby obtaining a predetermined predetermined solid. A method for obtaining an ore slurry having a component ratio (Solid%) was found, and the present invention was completed.

  That is, the present invention is a thickener device used in a production process of an ore slurry, which is lower than a predetermined solid component ratio intended for thickening a first raw ore slurry obtained by blending a plurality of types of ores. A first thickener for obtaining an ore slurry having a first solid component ratio, and an ore having a second solid component ratio that is higher than a predetermined solid component ratio intended for a second raw ore slurry obtained by blending a plurality of types of ores. A second thickener capable of obtaining a slurry, an ore slurry having a first solid component ratio obtained by the first thickener and an ore slurry having a second solid component ratio obtained by the second thickener are mixed and delivered. Ore slurry mixing section, ore slurry having the first solid component ratio and ore slurry having the second solid component ratio to be mixed by the ore slurry mixing section A mixing ratio control unit for controlling the mixing ratio of the first or more solid component ratio ore slurry and the second solid component ratio ore slurry in the ore slurry mixing unit by the mixing ratio control unit. Is controlled to a mixing ratio at which an ore slurry having a predetermined solid component ratio is obtained, and the ore slurry having a predetermined solid component ratio is delivered from the ore slurry mixing section.

  The present invention is also a method for controlling the solid component ratio of ore slurry in the ore slurry manufacturing process, wherein the first raw material ore slurry obtained by blending a plurality of types of ores is thickened by a first thickener for the intended purpose. An ore slurry having a first solid component ratio lower than the solid component ratio is obtained, and the second raw material ore slurry obtained by blending a plurality of types of ores is thickened by a second thickener to obtain a predetermined solid. An ore slurry having a second solid component ratio higher than the component ratio is obtained, and the ore slurry having the first solid component ratio and the first solid component ratio are obtained based on the first solid component ratio and the second solid component ratio. The mixing ratio of the ore slurry having a solid component ratio of 2 is controlled to a mixing ratio at which the ore slurry having the predetermined solid component ratio is obtained, and the ore slurry having the first solid component ratio is obtained. By mixing the ore slurry over and the second solid component ratio, wherein the obtaining the ore slurry predetermined solid component ratio to the object.

  In the present invention, the ore slurry production process is a production process of a nickel oxide ore slurry of 2 mm or less blended with, for example, nickel grade intended for sending to the high temperature pressurized sulfuric acid leaching process and other impurity grades, The mixing ratio of the nickel oxide ore slurry having a solid component ratio of 1 and the nickel oxide ore slurry having the second solid component ratio is controlled so that the target solid component ratio is 36 to 45%, preferably 39 to 42%. The nickel oxide ore slurry can be obtained.

  In the present invention, an ore slurry having a first solid component ratio lower than a target predetermined solid component ratio is obtained from a first raw material ore slurry obtained by blending a plurality of kinds of ores with a first thickener, and a plurality of kinds of ore slurries are obtained. An ore slurry having a second solid component ratio lower than a predetermined predetermined solid component ratio is obtained from a second raw material ore slurry blended with ore by a second thickener, and the first solid component ratio and the first solid component ratio are obtained. Based on the solid component ratio of 2, the mixing ratio of the ore slurry of the first solid component ratio and the ore slurry of the second solid component ratio is controlled, and the ore slurry of the first solid component ratio and the above By mixing the ore slurry having the second solid component ratio, an ore slurry having the above-mentioned predetermined solid component ratio can be obtained, and the target ore is not affected by the ore type and blend ratio. It can be obtained ore slurry of the solid component ratio.

  According to the present invention, in the nickel oxide ore slurry manufacturing process in the hydrometallurgical process based on high temperature pressure sulfuric acid leaching to recover nickel from low grade nickel oxide ore, the objective and The ore slurry having a solid component ratio can be sent to the high temperature pressure leaching process.

It is sectional drawing which shows typically the structure of the thickener apparatus to which this invention is applied. It is a flowchart which shows the procedure of the thickening process using the said thickener apparatus. It is a figure which shows the result of having investigated the relationship between the Si quality in the ore slurry in 3 types of thickeners (A, B, C) and Solid%. The relationship between Si grade and Solid% in the ore slurry obtained using only thickener A and thickener B having a large thickening effect, and the ore slurry obtained using the above two kinds of thickeners, thickener A and thickener B, are predetermined. It is a figure which shows the Si quality in the ore slurry mixed by the ratio of this, and the relationship of Solid%. 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 method for controlling the solid component ratio of ore slurry in the ore slurry manufacturing process according to the present invention is implemented by, for example, a thickener device 100 having a configuration as shown in FIG.

  In the method for controlling the solid component ratio of the ore slurry in the ore slurry manufacturing process according to the present invention, the first raw material ore slurry A0 obtained by blending a plurality of types of ores is thickened by the first thickener 10A and the target predetermined solid is obtained. The ore slurry A1 having a first solid component ratio lower than the component ratio is obtained, and the second raw ore slurry B0 obtained by blending a plurality of types of ores is thickened by the second thickener 10B to obtain a predetermined solid. An ore slurry B1 having a second solid component ratio higher than the component ratio is obtained, and based on the first solid component ratio and the second solid component ratio, the ore slurry A1 having the first solid component ratio and The mixing ratio of the ore slurry B2 having the second solid component ratio is controlled to the mixing ratio at which the ore slurry C having the predetermined solid component ratio is obtained. By mixing one ore slurry A1 and ore slurry B1 of the second solid component of the solid component ratio to obtain the ore slurry C of a predetermined solid component ratio to the object.

  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 supplied with a first raw ore slurry A0 in which a plurality of types of ores are blended. 10A, a second thickener 10B supplied with a second raw ore slurry B0 blended with a plurality of types of ores, and a first thickener 10A obtained by thickening the first raw ore slurry A0 with the first thickener 10A. A first extraction pump 21A for extracting one ore slurry A1 from the first thickener 10A, and a second ore slurry B1 obtained by thickening the second raw ore slurry B0 with the second thickener 10B. A second extraction pump 21B extracted from the second thickener 10B, and the first extraction pump; 21A and the control part 20 which controls operation | movement of the 2nd extraction pump 21B, 1st ore slurry A1 taken out from said 1st thickener 10A via said 1st extraction pump 21A, and said 1st thickener 10B And a mixing tank 30 to which the second ore slurry B1 taken out through the second extraction pump 21B is supplied. And this thickener apparatus 100 sends the 3rd ore slurry C taken out from the said mixing tank 30 through the 3rd extraction pump 31 to a high temperature pressurization sulfuric acid leaching process.

  The thickener device 100 includes a first ore slurry A1 and a second ore that are supplied to the mixing tank 30 by controlling the operations of the first extraction pump 21A and the second extraction pump 21B by the control unit 20. By controlling the supply amount of the slurry B1, the mixing ratio of the first ore slurry A1 and the second ore slurry B1 in the mixing tank 30 can be controlled.

  The first thickener 10A includes a thickener body 13A including a cylindrical outer frame 11A and a conical bottom portion 12A that gradually decreases toward the center. A rake 14A is disposed in the thickener body 13A along the inner surface of the conical bottom 12A. The rake 14A is rotationally driven by a rake rotary motor 15A connected to the rotary shaft.

  The first thickener 10A is supplied with the first raw ore slurry A0, flocculant and dilution water that are subjected to sedimentation concentration. The first raw ore slurry A0 supplied into the first thickener 10A settles and agglomerates in a mixed state with a flocculant and dilution water, so that the upper supernatant liquid portion and the lower sediment concentration are obtained. And is recovered as an ore slurry A1 having a first solid component ratio lower than a predetermined solid component ratio from a slurry recovery port provided at the lowermost portion of the first thickener 10A. The rake 14A is slowly rotated by a rake rotating motor 15A connected to the rotating shaft thereof, so that the slurry is settled and concentrated in the sedimentation concentration section, and a uniform deposition state is ensured. The ore slurry A1 having the first solid component ratio recovered from the first thickener 10A is supplied to the mixing tank 30 via the first extraction pump 21A.

  The second thickener 10B includes a thickener body 13B including a cylindrical outer frame 11B and a conical bottom portion 12B that gradually decreases toward the center. Inside the thickener body 13B, a rake 14B is disposed along the inner surface of the conical bottom 12B. The rake 14A is rotationally driven by a rake rotating motor 15B connected to the rotating shaft.

  The second thickener 10B is supplied with the second raw ore slurry B0, flocculant and dilution water to be subjected to sedimentation concentration. The second raw ore slurry B0 supplied into the second thickener 10B settles and agglomerates in a mixed state with a flocculant and dilution water, thereby concentrating the upper supernatant and lower sediments. And is recovered as an ore slurry B1 having a second solid component ratio higher than a predetermined solid component ratio from a slurry recovery port provided at the lowermost portion of the second thickener 10B. The rake 14B is slowly rotated by a rake rotation motor 15B connected to the rotation shaft thereof, so that the slurry is concentrated and settled in the sedimentation concentration section, and a uniform deposition state is ensured. The ore slurry B1 having the second solid component ratio recovered from the second thickener 10B is supplied to the mixing tank 30 via the second extraction pump 21B.

  In the thickener device 100, the first ore slurry A1 and the second ore are supplied to the mixing tank 30 by controlling the operations of the first extraction pump 21A and the second extraction pump 21B by the control unit 20. By controlling the supply amount of the ore slurry B1, the mixing ratio of the ore slurry A1 having the first solid component ratio and the ore slurry B1 having the second solid component ratio is the third target in the mixing tank 30. The ore slurry C having a solid component ratio of 3 is controlled to a mixing ratio to obtain an ore slurry C having a third solid component ratio.

  That is, in the mixing tank 30, the ore slurry A1 having a first solid component ratio lower than the target solid component ratio recovered from the first thickener 10A and the second thickener 10B are recovered. By mixing the ore slurry B1 having the second solid component ratio lower than the predetermined solid component ratio, the ore slurry C having the target third solid component ratio is generated. And the ore slurry C of the target 3rd solid component rate taken out from the said mixing tank 30 through the 3rd extraction pump 31 is sent to a high temperature pressurization sulfuric acid leaching process.

  Thickening processing using the thickener device 100 is performed according to the procedure shown in the flowchart of FIG.

  That is, in the first ore slurry blending process (S1), a plurality of types of ores are blended to generate the first raw ore slurry A0, and the generated first raw ore slurry A0 is supplied to the first thickener 10A. Then, the ore slurry A1 having the first solid component ratio lower than the target predetermined solid component ratio is obtained by the thickening process (S2) by the first thickener 10A.

  In the second ore slurry blending process (S3), a plurality of types of ores are blended to generate a second raw ore slurry B0, and the generated second raw ore slurry B0 is supplied to the second thickener 10B. Then, the ore slurry B1 having the second solid component ratio lower than the target predetermined solid component ratio is obtained by the thickening process (S4) by the second thickener B1.

  Then, in the mixing tank 30, the blending process (S5) of mixing the ore slurry A1 having the first solid component ratio and the ore slurry B1 having the second solid component ratio is performed to obtain the predetermined predetermined target. An ore slurry C having a solid component ratio is obtained, and a blended ore slurry delivery process (S5) is performed in which the target ore slurry C having a predetermined solid component ratio is delivered from the mixing tank 30.

  The mixing ratio for obtaining the target ore slurry C having the third solid component ratio from the ore slurry A1 having the first solid component ratio and the ore slurry B1 having the second solid component ratio is the first solid component ratio. The mixing tank 30 can be determined based on the solid component ratio and the second solid component ratio, and the operation of the first extraction pump 21A and the second extraction pump 21B is controlled by the control unit 20. The ore slurry A1 having the first solid component ratio and the ore slurry B1 having the second solid component ratio are controlled by controlling the supply amounts of the first ore slurry A1 and the second ore slurry B1 to be supplied to The ratio is controlled to the mixing ratio at which the target ore slurry C having the third solid component ratio is obtained in the mixing tank 30.

  Here, the ore slurry manufacturing process using this thickener device 100 is, for example, a manufacturing process of nickel oxide ore slurry of 2 mm or less blended with nickel grade intended for sending to the high-temperature pressurized sulfuric acid leaching process and other impurity grades. The mixing ratio of the nickel oxide ore slurry A1 having the first solid component ratio and the nickel oxide ore slurry B2 having the second solid component ratio is controlled so that the target solid component ratio is 36 to 45%. The nickel oxide ore slurry C of preferably 39 to 42% can be obtained.

  Table 1 shows the composition of typical nickel oxide ores used in the nickel hydrometallurgical process using the high-temperature pressurized sulfuric acid leaching method.

  Each of these nickel oxide ores has different thickening behavior in the thickener, acid consumption in the high-temperature pressure leaching process, oxidation-reduction potential (ORP), etc., so the composition of the ore slurry has a Ni grade of 1.0 to 1. .5, Mg + Al grade is about 1.5 to 4.5%, Si grade is about 3.0 to 8.0%, and C grade is about 0.12 to 0.20%. .

  The Mg + Al quality in the ore slurry affects the oxygen consumption in the high temperature pressure leaching process, and the C quality affects the ORP in the high temperature pressure leaching process. In addition, there is a strong correlation between the Si quality in the ore slurry and the thickening behavior in the thickener. The result of investigating the relationship between the Si grade in the ore slurry and Solid% in three types of thickeners (A, B, C) is shown in FIG.

  As shown in FIG. 3, the higher the Si quality in the ore slurry, the lower the Solid% of the resulting ore slurry, and the relationship between the Si quality and Solid% differs depending on the shape and size of the thickener used. I can see that It can be seen that the thickening effect is higher in the order of B, C, and A. Solid% of the ore slurry obtained using ore blended so that the Si grade in the ore slurry is 6 to 7% is 37 to 38% when thickener A is used, and when thickener B is used. Will yield 42-44% Solid% ore slurry. As described above, it is desirable that the solid% of the ore slurry to be sent to the high-temperature pressure leaching process is high, but if it is too high, the viscosity of the ore slurry will increase, so it is necessary to set the proper solid% (39 to 42%). .

  Next, the relationship between Si grade and Solid% in the ore slurry obtained using only thickener A and thickener B having a large thickening effect, and the above two kinds of thickeners, thickener A and thickener B, are used. FIG. 4 shows the relationship between the Si grade and Solid% in the ore slurry obtained by mixing the predetermined Solid% ore slurry obtained in step 1 at a predetermined ratio.

  Here, the two types of thickeners, the thickener A and the thickener B, correspond to the first thickener 10A and the second thickener 10B in the thickener device 100.

  The mixing ratio of the slurry from the thickener A and the thickener B, that is, the mixing ratio of the first ore slurry A1 and the second ore slurry B1 obtained by the first thickener 10A and the second thickener 10B in the thickener device 100. The decision was made as follows. First, after determining the blend ratio of the raw ore slurries A0 and B0 to be sent to thickener A and thickener B, Solid% estimated by each thickener was calculated from the relationship shown in Table 2. Next, the mixing ratio of the ore slurry obtained from each thickener was determined to be the target Solid%.

  Specifically, as shown in Table 3, the mixing ratio of thickener A and thickener B was determined so that the Solid% in the ore slurry after mixing was 39 to 42%.

  As described above, the Solid% of the ore slurry C is preferably 39 to 42%. As shown in FIG. 4, the solid% of the ore slurry obtained using only thickener A and thickener B decreases with the increase in the Si grade in the ore slurry. Yes. With thickener A alone, when the Si grade is 4.0 to 5.5%, the Solid% is 39 to 42%, which is the optimal Solid%. However, when the Si grade is 6.0% or more, the Solid% is 39% or less. It will go down. On the other hand, with thickener B alone, when the Si quality is 6.5% or less, the Solid% is 42% or more. In the thickener device 100, a substantially constant Solid% (39 to 42%) ore slurry C is obtained regardless of the increase in Si quality. Thus, obtaining an optimal Solid% ore slurry regardless of the variation in Si grade in the ore slurry is very effective by performing an operation with high Ni recovery efficiency.

  10A first thickener, 10B second thickener, 11A, 11B cylindrical outer frame, 12A, 12B bottom, 13A, 13B thickener body, 14A, 14B rake, 15A, 15B rake rotary motor, 21A first extraction pump, 21B 2nd extraction pump, 20 controller, 30 mixing tank, 31 3rd extraction pump, 100 thickener device, A0 first raw material ore slurry, B0 second raw material ore slurry, A1 of first solid component ratio Ore slurry, B1 Ore slurry with second solid component ratio, C Ore slurry with predetermined solid component ratio

Claims (6)

A thickener device used in the production process of ore slurry,
A first thickener for thickening a first raw ore slurry blended with a plurality of types of ores to obtain an ore slurry having a first solid component ratio lower than a predetermined solid component ratio;
A second thickener for thickening the second raw ore slurry blended with a plurality of types of ores to obtain an ore slurry having a second solid component ratio higher than a predetermined solid component ratio;
An ore slurry mixing section for mixing and sending the first solid component ratio ore slurry obtained by the first thickener and the second solid component ratio ore slurry obtained by the second thickener;
A mixing ratio control unit that controls a mixing ratio of the ore slurry having the first solid component ratio and the ore slurry having the second solid component ratio to be mixed by the ore slurry mixing unit;
An ore slurry having a predetermined solid component ratio is used as the mixing ratio of the ore slurry having the first solid component ratio and the ore slurry having the second solid component ratio in the ore slurry mixing unit by the mixing ratio control unit. A thickener device characterized in that the ore slurry having a predetermined solid component ratio is delivered from the ore slurry mixing section while controlling the obtained mixing ratio. The ore slurry production process is a production process of nickel oxide ore slurry of 2 mm or less blended with nickel grade intended for sending to the high-temperature pressurized sulfuric acid leaching process and other impurity grades,
The mixing ratio control unit controls the mixing ratio of the nickel oxide ore slurry having the first solid component ratio and the nickel oxide ore slurry having the second solid component ratio in the ore slurry mixing unit, thereby mixing the ore slurry. The thickener device according to claim 1, wherein a nickel oxide ore slurry having a target solid component ratio of 36 to 45% is delivered from a section.   The thickener device according to claim 2, wherein a nickel oxide ore slurry having a target solid component ratio of 39 to 42% is delivered from the ore slurry mixing section. A method for controlling a solid component ratio of an ore slurry in an ore slurry manufacturing process,
A first raw material ore slurry obtained by blending a plurality of types of ores is thickened by a first thickener to obtain an ore slurry having a first solid component ratio lower than a predetermined solid component ratio. Thickening the second raw ore slurry blended with the ore with a second thickener to obtain an ore slurry having a second solid component ratio higher than a predetermined solid component ratio,
Based on the first solid component ratio and the second solid component ratio, the mixing ratio of the ore slurry having the first solid component ratio and the ore slurry having the second solid component ratio is a predetermined ratio for the purpose. By controlling the mixing ratio to obtain an ore slurry with a solid component ratio,
The ore slurry having the predetermined solid component ratio is obtained by mixing the ore slurry having the first solid component ratio and the ore slurry having the second solid component ratio. Component rate control method. The ore slurry production process is a production process of nickel oxide ore slurry of 2 mm or less blended with nickel grade intended for sending to the high-temperature pressurized sulfuric acid leaching process and other impurity grades,
The mixing ratio of the nickel oxide ore slurry having the first solid component ratio and the nickel oxide ore slurry having the second solid component ratio is controlled to obtain a nickel oxide having a predetermined solid component ratio of 36 to 45%. An ore slurry is obtained, The solid component rate control method of the ore slurry of Claim 4 characterized by the above-mentioned.   6. The method for controlling the solid component ratio of an ore slurry according to claim 5, wherein a nickel oxide ore slurry having a target solid component ratio of 39 to 42% is obtained.