JP2020041171A - Liquid transferring method for slurry and transportation device for slurry - Google Patents

Abstract

To provide a method and a device configuration capable of liquid transferring a condensed slurry containing metal hydroxide or metal oxide as particles at high concentration by a slurry pump.SOLUTION: There is provided a liquid transferring method for slurry which is a mixed body of a solid component and a liquid component, including heating the slurry consisting of the liquid component and the solid component constituted only by particles of which 90% or more has particle size distribution of 100 μm or less and which has particle diameter of 1.4 mm or less, and having concentration of the solid component of 15 mass% or more to a temperature range of 60°C to 70°C to form a heated slurry, and liquid transferring the heated slurry by force of a slurry pump.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for transporting a slurry concentrated to a high concentration by a thickener, a system or a device configuration for transporting the slurry, and more particularly, to a slurry containing solid particles such as a metal hydroxide or a metal oxide. A method of allowing the slurry to be transported by a slurry pump by reducing only the viscosity while maintaining the concentration high, with respect to the slurry having a high concentration and a high viscosity which is concentrated by a thickener. And a device configuration therefor.

In recent years, as a wet smelting method for recovering valuable metals from nickel oxide ores, a high-pressure acid leaching method using sulfuric acid (High Pressure Acid Leach: hereinafter sometimes referred to as the HPAL method) is used. .
The HPAL method is, for example, a leaching treatment method in which sulfuric acid is added to an ore slurry and leached under high temperature and high pressure to obtain a leaching solution containing nickel and cobalt. Examples of the ore slurry include a slurry containing nickel oxide ore in the form of a metal hydroxide or a metal oxide.

A leaching step to which the HPAL method is applied, a neutralization step of adjusting the pH of the obtained leachate to form a neutralized precipitate slurry containing an impurity element such as iron and a purified mother liquid for nickel recovery, and A smelting method including a step of supplying hydrogen sulfide gas to the mother liquor for nickel recovery to form a mixed sulfide of nickel and cobalt and a poor solution has been performed (for example, see Patent Document 1).
In this smelting method, 90% or more of nickel or cobalt in the ore slurry is generally leached in the leaching step. Then, after the leachate is separated, impurities in the leachate are separated and removed by a neutralization method to obtain a nickel-cobalt mixed sulfide having a nickel grade of about 55 to 60% and a cobalt grade of about 3 to 6%. Used as an intermediate material in nickel and cobalt smelting.

By the way, the raw material ore such as nickel oxide ore used in the above-mentioned smelting process or the like is usually subjected to ore treatment and prepared for charging into the smelting process to become an ore slurry, and the ore slurry is formed. And used in leaching and the like.
As the ore treatment of the raw ore, specifically, a crushing / classifying step of subjecting the raw ore to a crushing treatment and a multi-stage classification (sieving) treatment, and an ore for concentrating solid components in the slurry It is roughly divided into a slurry concentration step.

First, in the crushing / classifying stage, the raw material ore is crushed by a wet facility, and the classification process of removing oversized ore particles and contaminants is performed to produce a coarse ore slurry composed of undersized ore particles. (For example, see Patent Document 2).
Then, since the coarse ore slurry produced here contains excess water, excess water is removed in the next ore slurry concentration step (for example, see Patent Document 3). . This moisture removal results in a concentrated slurry in which the ore component contained in the ore slurry per the same transfer amount is increased, thereby contributing to an improvement in the operation efficiency of the entire plant.

However, in the conventional ore processing as described above, the size of the ore particles fluctuates or the ore particles of various sizes coexist depending on the fluctuation of the particle size of the input raw ore and the degree of crushing in the crushing process. Or as a result, the viscosity of the obtained ore slurry may be too high.
Similarly, particles such as metal hydroxides and metal oxides generated by a chemical reaction in the subsequent process may vary in particle size, and particles of various sizes may coexist. The viscosity of the resulting slurry may be too high.

By the way, Patent Literature 4 discloses a method for sending a slurry, but it is directed to a mixed slurry of terephthalic acid and water, which are organic compounds, and is treated differently from metal smelting. A method for improving the transportability of a slurry of a metal hydroxide or a metal oxide, which is an inorganic compound and has the properties of a bingham slurry, is also desired from the following viewpoints.
For the transportation of a slurry having a high viscosity, a method of sending the liquid by a slurry pump after reducing the viscosity of the slurry or a method of sending the liquid by a pump having a larger transport force corresponding to the higher viscosity may be mentioned. However, if it becomes possible to send a slurry with a higher concentration without increasing the slurry volume such as dilution in that state, the processing flow rate of the entire smelter will be reduced, and the construction cost of the smelter will be reduced. Since it is possible to reduce power consumption and running cost related to liquid feeding in the entire smelter, there has been a demand for a method for sending a more concentrated slurry.

JP 2005-350766 A JP 2009-173967 A JP-A-11-124640 JP 2006-143612 A

  The present invention has been proposed in view of such circumstances, and a method and an apparatus for allowing a concentrated slurry containing a metal hydroxide or a metal oxide in a high concentration as particles to be sent by a slurry pump. Provide configuration.

  The present inventor has conducted intensive studies to achieve the above-described object, and as a result, regarding the slurry concentrated to a high concentration by the thickener, increasing the temperature of the slurry that has been conventionally sent at normal temperature, the concentrated slurry And found that the high-concentration slurry, which had been considered impossible to be fed, could be sent, and the present invention was completed.

  The first invention of the present invention is a method for feeding a slurry which is a mixture of a solid component and a liquid component, wherein the particle size of the liquid component and 90% or more of which has a particle size distribution of 100 μm or less is 1.4 mm or less. After forming the slurry comprising a solid component composed of only particles of the above and having a solid component concentration of 15% by mass or more into a heated slurry heated to a temperature range of 60 ° C. to 70 ° C., This is a method for sending a slurry, wherein the hot slurry is sent by the power of a slurry pump.

The second invention of the present invention is a method for feeding a slurry, which is a mixture of a solid component and a liquid component, wherein the liquid component has a particle size distribution in which 90% or more and a particle size distribution of 100 μm or less are 1.4 mm. After forming the slurry comprising a solid component composed of only the following particles and having a yield stress of 400 Pa or less into a heated slurry heated to a temperature range of 60 ° C. to 70 ° C., the heated slurry is subjected to a slurry pump. A method for feeding a slurry, characterized in that the solution is fed by the power of (1).
Furthermore, a third invention of the present invention is the method for feeding a slurry, wherein the yield stress of the heated slurry in the second invention is 50% or less of the yield stress of the slurry before heating. .

  A fourth invention of the present invention is the slurry sending method, wherein the slurry in the first to third inventions is an ore slurry obtained by crushing and classifying nickel ore.

  A fifth aspect of the present invention is a method for sending a slurry, wherein the slurry according to the first to fourth aspects contains a coagulant.

  According to a sixth aspect of the present invention, there is provided a slurry transport apparatus in which a slurry is fed in a pipe by the power of a slurry pump, wherein the liquid component has a particle size of 90% or more and a particle size distribution of 100 μm or less. A pipe composed of a solid component composed of only particles of 0.4 mm or less and having a concentration of the solid component of 15% by mass or more and a yield stress of 400 Pa or less. A slurry transport device, wherein a heating device for heating the slurry is provided.

  According to a seventh aspect of the present invention, in the heating apparatus according to the sixth aspect, the heating device forms the heated slurry having a slurry temperature of 60 ° C to 70 ° C from the slurry in the normal temperature range of 20 ° C to 40 ° C. An apparatus for transporting slurry, which is an apparatus.

  An eighth invention of the present invention is the slurry transport device according to the sixth invention, wherein the concentration device is a thickener.

  ADVANTAGE OF THE INVENTION According to this invention, it is a slurry which contains a metal hydroxide or a metal oxide as a particle, and the method of enabling the slurry which particle density | concentration was thickened by the thickener to be able to send, and the apparatus structure which enables a liquid sending are provided. be able to. And by introducing such a method, even if the slurry handled in the entire smelter is concentrated, it can be transferred by pumps and small pipes with the minimum necessary transport power, and efficient operation can be performed. And has an industrially remarkable effect.

It is a schematic diagram showing the device composition concerning the present invention. It is a process figure of the hydrometallurgy method of nickel oxide ore. It is a flowchart of the manufacturing method of ore slurry.

Hereinafter, specific embodiments of the present invention (hereinafter, referred to as the present embodiment) will be described in detail in the following order with reference to the drawings. Note that the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.
1. A method for reducing the viscosity of highly concentrated slurries.
2. Metal smelting method to which this embodiment is applied (nickel oxide ore wet smelting method).

<1. Method for reducing viscosity of highly concentrated slurry>
Examples of the slurry according to the present embodiment include a slurry in which crushed ore is suspended in an aqueous solution, and a slurry in which alkali is added to an aqueous solution to precipitate particles.

FIG. 1 is a schematic diagram showing the configuration of an apparatus for performing a method of reducing the viscosity of a high-concentration concentrated slurry applied to sending of a concentrated slurry according to the present embodiment.
10 is a thickener, 10A is a thickener can, 11 is a motor, 15 is a slurry inlet, 16 is an overflow outlet, 17 is an underflow outlet, 20 is a heating device, Sin is coarse ore slurry, OF is overflow, UF Is an underflow (ore slurry: high concentration slurry), 20 is a heating device, 21 is an underflow line (piping), and Sout is a heating slurry.
A concrete embodiment of the method for reducing the viscosity of the slurry is to arrange a heating device 20 for heating the slurry in the underflow line 21 of the thickener 10 for concentrating the slurry, and to concentrate the high concentration of particles separated by the thickener. The heating of the slurry is performed by appropriately selecting a heating heater using a steam trace, steam heating using a static mixer, or indirect heating using a heat exchanger. The method is not limited to these as long as it can be heated.

Here, the concentrated slurry of the underflow component flowing out of the thickener 10 has a slurry concentration indicating a solid component ratio in the slurry of 15% by mass or more, preferably 50% by mass or less, for example, 45% by mass. The present embodiment is applicable to the concentrated slurry before and after.
In such a concentrated slurry having a high slurry concentration, the viscosity of an object can be used as an index indicating the ease of liquid sending when the liquid is sent through the pipe by the pressure from the slurry pump. In this case, since the numerical value changes depending on the shape factor of the pipe (such as the pipe diameter and the pipe length), it is not easy to show the relationship between the physical properties of the slurry to be sent and the capacity of the slurry pump.

Then, the viscous dynamic friction torque T due to the slurry is observed with a coaxial double cylindrical viscometer, and “shear stress S [Pa]” corresponding to the viscous friction resistance of the slurry is calculated by the following equation (1).
Therefore, the yield stress τ _y is obtained by the following equation (2). Note that _Rb is ｍ [m] of the outer diameter of the inner cylinder rotating body, and h is the length [m] of the inner cylinder rotating body.

From the yield stress of the slurry, the power required for transportation, that is, the capacity of the slurry pump is determined as follows.
Here, the ore slurry generally shows Bingham flow characteristics among non-Newtonian fluids, and a fluid having Bingham flow characteristics (hereinafter referred to as Bingham fluid) generally has a shear rate of 0 [1 / s]. At certain times, it does not flow unless an external force greater than the yield stress is applied, and behaves like a solid. When an external force equal to or higher than the yield stress is applied to the Bingham fluid, fluidization starts and the fluid exhibits properties. In general, the Bingham fluid has a property called a shear thinning effect, in which the viscosity decreases as the shear rate increases.

  Therefore, in the present embodiment, in order to properly consider the influence of the "shear thinning effect" due to the shear rate acting on the slurry in the pipe, the yield stress (the above (2)) obtained from the measurement result of the coaxial double cylindrical viscometer is used. The apparent viscosity μ [Pa / s] of the ore slurry flowing in the pipe was calculated from the equation (3) using a conversion equation shown in the following equation (3).

Here, μ is viscosity [Pa / s], τ _y is yield stress [Pa], τ _w is liquid level shear stress [Pa], V is average flow velocity in pipe [m / s], D is pipe inner diameter [m]. , Le represent the pipe equivalent length [m], and ΔP represents the friction pressure loss [Pa].
Next, the Reynolds number Re is determined by the following equation (4) using the determined apparent viscosity μ and the density of the ore slurry ρ [kg / m ³ ].

Here, the Reynolds number is a dimensionless number for determining whether a fluid is in a laminar state or a turbulent state. In the case of a Newtonian fluid such as water, Re = 2000 to 2300 is generally a threshold value of the laminar turbulent flow. However, in the case of the Bingham fluid, this threshold value tends to be low, and in the present embodiment, the threshold value is set to Re = 1000.
Next, the pipe friction pressure loss ΔP _fric is calculated using the “Darcy-Weissbach equation” of the following equation (5).

  Here, λ is called a friction coefficient. In the case of a laminar flow, it is analytically obtained by λ = 64 / Re. However, in the case of a turbulent flow, it cannot be analytically obtained. Proposed. In the present embodiment, in the case of a turbulent flow, λ is obtained using “Colebrook's equation” shown in the following equation (6), which is considered to have high accuracy for a system having a relatively rough pipe inner wall.

  Here, ε represents the absolute roughness [mm] of the inner surface of the pipe, and the friction pressure loss is determined by the above calculation formula and procedure.

Next, the procedure for calculating the required pressure and power consumption of the slurry pump will be described.
The required energy required for the pump is calculated by the following equation (7), where P _all is the required pressure, ΔP _{fric is the} friction pressure loss, ΔP _{h is} the head drop term, and ΔP _V is the speed term.

Here, ΔP _h and ΔP _V are obtained by the following equation (8). g is the gravitational acceleration [m / s ² ], and ΔH is the head [m].

Accordingly, the required shaft power P _ax [W] of the pump is calculated by the following equation (9) in consideration of the efficiency η ₁ [%] representing the typical performance of the pump.
Finally, the expected value P _m [W] of the power consumption of the pump is calculated by the following equation (10).

Here, Q is a flow rate [m ³ / hr], e is a margin [%] set when designing the pump, and η ₂ is a conduction efficiency of energy transmitted from the motor to the shaft.

From the above equations (1) to (10), it is understood that by setting the yield stress of the concentrated slurry having a high slurry concentration to a small value, the liquid can be easily sent in the pipe. In order to reduce the yield stress, it is effective to raise the slurry temperature by heating the slurry so that a concentrated slurry such as a thickener underflow can be easily sent by a low capacity pump. Become.
The heating condition is to warm the temperature of the concentrated slurry discharged as an underflow component from the thickener 10 used for heating from room temperature (20 ° C to 40 ° C) to 60 ° C to 70 ° C.

Under such heating conditions, the yield ratio of the concentrated slurry before and after the heating becomes 0.5 or less, which facilitates the transfer of the concentrated slurry. When the stress ratio exceeds 0.5, higher performance is required for the slurry pump, and it becomes difficult to procure the pump.
In consideration of the above-mentioned properties of the concentrated slurry and the performance of the slurry pump, the concentrated slurry that can be used in the present embodiment has a maximum yield stress of 200 to 400 [MPa] in order to send liquid in a pipe. A concentrated slurry having a slurry concentration of 15% by mass or more, preferably 50% by mass or less, for example, about 45% by mass is suitable.

<2. Metal smelting method (nickel oxide ore wet smelting method)>
Therefore, next, a description will be given of a hydrometallurgical method for recovering nickel and cobalt from a nickel oxide ore by the HPAL method using the ore slurry produced by the above-described method for producing an ore slurry.

  FIG. 2 shows an example of a process diagram of a hydrometallurgical method for nickel oxide ore by a high-temperature pressurized acid leaching method. As shown in FIG. 2, the hydrometallurgical method of nickel oxide ore comprises an ore slurry production step S21 of pulverizing and classifying nickel oxide ore and concentrating solid components in the slurry to produce ore slurry. Leaching step S22 for leaching nickel and cobalt from the ore slurry obtained, solid-liquid separation step S23 for solid-liquid separation from the obtained leaching slurry into a leaching solution and a leaching residue, a mother liquor for neutralizing the leaching solution and recovering nickel. It has a neutralization step S24 for separating into a wet slurry, and a sulfurization step S25 for injecting hydrogen sulfide gas into sulfuric acid as a mother liquor to perform a sulfurization reaction to obtain a sulfide containing nickel and a poor solution. Hereinafter, each step will be described more specifically.

(Ore slurry production process)
In the ore slurry production process S21, first, nickel oxide ore as a raw material ore is crushed, classified at a predetermined classification point, and a coarse ore slurry composed of undersized ore particles and water obtained by the classification is produced. . Then, an ore slurry is produced by removing water from the obtained crude ore slurry by a solid-liquid separation treatment and concentrating a solid component (ore component).

More specifically, the ore slurry manufacturing step S21 in the metal smelting method according to the present embodiment shown in FIG. 3 crushes the raw ore, classifies it at a predetermined classification point, and removes oversized ore particles. Crushing / classifying step S1 for obtaining a coarse ore slurry composed of undersized ore particles and water, a particle size measuring step S2 for measuring the particle size of the coarse ore slurry obtained in the crushing / classifying step, Is charged into a solid-liquid separation device, and passes through an ore slurry concentration step S3 of separating and removing water contained in the coarse ore slurry to concentrate ore components, whereby a predetermined 90% or more according to the present embodiment is 100 μm. A concentrated ore slurry having a high slurry concentration and having a solid component and a liquid component composed of only particles having a particle size distribution of 1.4 mm or less and having the following particle size distribution is prepared.
Further, the ore slurry concentrated to a high concentration obtained through the ore slurry concentration step S3 is supplied to the heating device indicated by reference numeral 20 in FIG. In the slurry heating treatment step S4 in which a heating treatment is performed when passing, the slurry concentration is maintained without changing before and after receiving the heating treatment, that is, the yield is easy to send while the slurry concentration is high. The slurry is converted into a concentrated slurry (warmed slurry) exhibiting stress and transferred to the leaching step S22 via a slurry pump (transfer pump).

  In the ore slurry production step S21, when the particle size of the coarse ore slurry measured in the particle size measurement step S2 falls below a predetermined value, the oversized ore particles removed in the crushing / classification step S1 are removed. A part is charged and added to the solid-liquid separator in the ore slurry concentration step S3.

  According to such an ore slurry production process S21, an ore slurry in which an increase in slurry viscosity is suppressed can be produced, and the next process can be performed using a general transfer pump without causing transfer failure or the like. Can be efficiently transferred to the leaching step.

  The slurry concentration (solid component concentration) of the ore slurry produced in the ore slurry production step S21 is not particularly limited, but is adjusted to a target of 15 to 45% by mass or 45 to 50% by mass. Is preferred.

(Leaching process)
In the leaching step S22, sulfuric acid is added to the ore slurry obtained in the ore slurry manufacturing step S21, and a stirring treatment is performed at a temperature of 220 ° C to 280 ° C to form a leaching slurry composed of a leaching solution and a leaching residue. In the leaching step S22, for example, a high-temperature pressurized container (autoclave) is used.

  Specifically, in the leaching step S22, a leaching reaction represented by the following formulas (A) to (E) and a high-temperature thermal hydrolysis reaction occurred, and leaching as a sulfate such as nickel and cobalt was performed. Immobilization of iron sulfate as hematite is performed. However, since the immobilization of iron ions does not proceed completely, the liquid portion of the obtained leach slurry usually contains divalent and trivalent iron ions in addition to nickel, cobalt and the like.

  The amount of sulfuric acid to be added in the leaching step S22 is not particularly limited, and an excess amount is used so that iron in the ore is leached. For example, 300 to 400 kg per ton of ore. If the amount of sulfuric acid added per ton of ore exceeds 400 kg, the cost of sulfuric acid is undesirably increased.

(Solid-liquid separation process)
In the solid-liquid separation step S23, the leaching slurry formed in the leaching step S22 is washed in multiple stages to obtain a leaching solution containing nickel and cobalt and a leaching residue.

  The multistage cleaning method in the solid-liquid separation step S23 is not particularly limited, but it is preferable to use a continuous countercurrent cleaning method (CCD method: Counter Current Decantation) in which the cleaning liquid containing no nickel is brought into countercurrent contact. . As a result, the amount of cleaning liquid newly introduced into the system can be reduced, and the recovery rate of nickel and cobalt can be 95% or more.

(Neutralization step)
In the neutralization step S24, calcium carbonate is added so that the pH of the leachate separated in the solid-liquid separation step S23 becomes 4 or less, and the mother liquor for nickel recovery and trivalent To form a neutralized precipitate slurry containing iron. In the neutralization step S24, by performing the neutralization treatment of the leachate in this way, the excess acid used in the leaching step S22 by high-temperature pressurized acid leaching is neutralized, and the trivalent remaining in the solution is removed. Removes iron ions and aluminum ions.

  The pH of the leachate adjusted in the neutralization step S24 is set to 4 or less as described above, and preferably 3.2 to 3.8. When the pH of the leaching solution exceeds 4, the generation of nickel hydroxide increases.

  Further, in the neutralization step S24, it is preferable not to oxidize iron ions existing as divalent in the solution when removing trivalent iron ions remaining in the solution. Therefore, it is preferable to minimize oxidation of the solution due to, for example, blowing air. Thereby, it is possible to suppress an increase in the consumption of calcium carbonate and the production of the neutralized precipitate slurry due to the removal of divalent iron. That is, it is possible to suppress nickel recovery loss to the precipitate due to an increase in the amount of the neutralized precipitate slurry.

  Further, the neutralized precipitate slurry obtained in the neutralization step S24 can be sent to the solid-liquid separation step S23 as needed. Thereby, nickel contained in the neutralized precipitate slurry can be effectively recovered. Specifically, the neutralized precipitate slurry is repeatedly subjected to a solid-liquid separation step S23 operated at a pH lower than that of the neutralization step S24, so that the leached residue is washed and water adhering to the neutralized precipitate is mixed with the neutralized precipitate slurry. The dissolution of nickel hydroxide generated by the local reaction on the surface of the hydrate can be promoted, and the water attached to the neutralized hydrate can be recovered in the leachate. Therefore, the nickel content that causes a recovery loss can be reduced.

  The reaction temperature in the neutralization step S24 is preferably set to about 50C to 80C. If the reaction temperature is lower than 50 ° C., the formed neutralized precipitate containing trivalent iron ions becomes fine, and its separation becomes difficult. On the other hand, when the reaction temperature exceeds 80 ° C., the corrosion resistance of the apparatus material is reduced and the energy cost for heating is increased.

(Sulfurization process)
In the sulfidation step S25, hydrogen sulfide gas is blown into the aqueous sulfuric acid solution, which is the mother liquor for nickel recovery, obtained in the neutralization step S24 to cause a sulfidation reaction, thereby generating a sulfide containing nickel and a poor solution.

  The mother liquor is sulfuric acid obtained by leaching the ore slurry as described above, and is obtained through the neutralization step S24. Specifically, for example, the pH is 3.2 to 4.0, the nickel concentration is 2 to 5 g / L, the cobalt concentration is 0.1 to 1.0 g / L, and iron, magnesium, Sulfuric acid containing manganese and the like. The content of the impurity component varies greatly depending on the oxidation-reduction potential of leaching, the operating conditions of the autoclave, and the ore grade, but generally contains about several g / L each of iron, magnesium, and manganese. Here, the impurity component is present in a relatively large amount with respect to nickel and cobalt to be recovered, but iron, manganese, alkali metal, magnesium, and other alkaline earth metals have low stability as sulfide, It is not contained in the generated sulfide.

  In addition, when zinc is contained in the mother liquor, a treatment for selectively separating zinc as sulfide can be performed prior to a treatment for producing nickel or the like as sulfide by a sulfidation reaction. As the treatment for selectively separating zinc, the coprecipitation of nickel having a higher concentration than that of zinc is suppressed by limiting the amount of the sulphidizing agent to be added to a small amount, and zinc is selectively removed.

  In the sulfidation step S25, a sulfide containing nickel with a low impurity content and a poor solution in which the nickel concentration is stabilized at a low level are generated and collected. Specifically, the sulfide slurry obtained by the sulfidation reaction is subjected to sedimentation treatment using a sedimentation / separation device such as a thickener to separate and collect the sulfide, which is a precipitate, from the bottom of the thickener. Some poor liquid is collected by overflowing. The poor solution has a pH of about 1 to 3, and contains impurity elements such as iron, magnesium, and manganese that remain without being sulfurized.

  In the sulfurizing step S25, a sulfide containing nickel (nickel sulfide) whose average particle diameter has been adjusted to be a predetermined size or more can be added as a seed crystal to the mother liquor for nickel recovery. This reduces the content of fine suspended solids containing nickel in the overflow solution during the sedimentation separation process of separating the sulfide slurry generated by the sulfidation reaction into the sulfide as a precipitate and the poor solution, It is possible to increase the amount of nickel precipitated and formed as a material, and to reduce the recovery loss of nickel.

  The amount of nickel sulfide to be a seed crystal is preferably 4 to 6 times the amount of nickel contained in the mother liquor. Thereby, the adhesion of the produced sulfide to the inner surface of the reaction vessel can be suppressed, and the nickel concentration in the poor solution can be stabilized at a much lower level.

  Further, the nickel sulfide added as the seed crystal is formed in the sulfidation step S25, and after being collected through the sedimentation separation process, the particle size is adjusted by a classification process or the like so that the average particle size becomes a predetermined size or more. Sulfides are preferred. In addition, you may perform the process which grinds a sulfide before a classification process as needed.

  Hereinafter, examples of the present embodiment will be described in detail, but the present embodiment is not limited to the following examples.

(Solution test)
Using the suspended thickener equipment, a heating device using a heating heater as a heating source is installed in a part of the underflow line, and one of the following Examples 1 to 3 and Comparative Examples 1 and 2 is installed from the upstream side. Is fed into its heating device, and while carrying out predetermined heating, the heated slurry (heated slurry) is suctioned by an attached transport pump to change the state of liquid supply to the pipe. The solution was formed and the solution was sent for about 24 hours, and the condition of clogging of the pipe was observed and evaluated.

After a nickel oxide ore is mixed with water to form a slurry, a lump having a particle size of 1.4 mm or more is removed and classified, whereby 90% or more of the particles have a particle size distribution of 100 μm or less. A slurry A was prepared as a test material having 50% by mass of a solid component composed only of particles having a size of 0.4 mm or less, and the remainder being liquid.
Next, the slurry A was heated and adjusted so that the slurry temperature would be 60 ° C. to 70 ° C., and supplied to the liquid sending test.
As a result, even when 24 hours had passed since the start of the liquid sending, the liquid sent could be sent without clogging.

In Example 1, a slurry B and a heated slurry _BH were prepared under the same conditions except that the content of nickel oxide ore was adjusted to 45% by mass, and subjected to a liquid sending test.
As a result, even when 24 hours had passed since the start of the liquid sending, the liquid could be sent without clogging with the sent slurry.

Even less than in Example 2, except that contained 15 wt% of nickel oxide ore, to prepare a slurry C, and warming the slurry C _H under the same conditions as in Example 1, was subjected to feeding tests.
As a result, even when 24 hours had passed since the start of the liquid sending, the liquid sent could be sent without clogging.

(Comparative Example 1)
In Example 1, the slurry A was subjected to a liquid sending test at room temperature without heating.
As a result, the clogging of the piping occurred 6 hours after the start of the liquid feeding, so the liquid feeding was stopped.
Table 1 summarizes the above results.

After a nickel oxide ore is mixed with water to form a slurry, a lump having a particle size of 1.4 mm or more is removed and classified, whereby 90% or more of the particles have a particle size distribution of 100 μm or less. Water (liquid) was added to a solid component composed of only particles of 0.4 mm or less to prepare a slurry D having a yield stress of 400 [Pa].
Next, the slurry D was heated and adjusted so that the slurry temperature became 60 ° C. to 70 ° C., and supplied to the liquid sending test.
As a result, the prepared slurry could be sent in the entire prepared amount without causing clogging of the piping. The yield stress after heating was 200 [Pa].

(Comparative Example 2)
The slurry D used in Example 4 was subjected to a liquid sending test without heating. As a result, the pipe was clogged within one minute after the start of the liquid feeding, so the liquid feeding was stopped.

10 Thickener 10A Thickener can 11 Motor 15 Slurry inlet 16 Overflow outlet 17 Underflow outlet 20 Heating device 21 Underflow line (piping)
Sin coarse ore slurry OF overflow UF underflow (ore slurry: concentrated slurry)
Sout heating slurry

Claims (8)

A method for sending a slurry that is a mixture of a solid component and a liquid component,
90% or more of the liquid component and a solid component composed of only particles having a particle size distribution of 1.4 mm or less having a particle size distribution of 100 μm or less,
After forming the slurry in which the concentration of the solid component is 15% by mass or more into a heated slurry warmed to a temperature range of 60 ° C to 70 ° C, sending the heated slurry by the power of a slurry pump. A method for feeding a slurry. A method for sending a slurry that is a mixture of a solid component and a liquid component,
90% or more of the liquid component and a solid component composed of only particles having a particle size distribution of 1.4 mm or less having a particle size distribution of 100 μm or less,
A slurry characterized in that the slurry having a yield stress of 400 Pa or less is formed into a heated slurry heated to a temperature range of 60 ° C. to 70 ° C., and then the heated slurry is fed by the power of a slurry pump. Liquid sending method.   The method according to claim 2, wherein the yield stress of the heated slurry is 50% or less of the yield stress of the slurry before heating.   The slurry sending method according to any one of claims 1 to 3, wherein the slurry is an ore slurry obtained by crushing and classifying nickel ore.   The method for feeding a slurry according to any one of claims 1 to 4, wherein the slurry contains a flocculant. A slurry transport device in which the slurry is sent through the pipe by the power of the slurry pump,
A liquid component and a solid component composed of only particles having a particle size distribution of 90% or more and a particle size distribution of 100 μm or less and a particle size of 1.4 mm or less, and the concentration of the solid component is 15% by mass or more, and the yield stress is: A slurry transport device, wherein a heating device for warming the slurry is installed in a pipe from which the slurry is discharged from a concentration device that forms a slurry having a pressure of 400 Pa or less.   The heating device according to claim 6, wherein the heating device is a heating device that forms a heated slurry having a slurry temperature of 60C to 70C from the slurry in a normal temperature region of 20C to 40C. Slurry transport equipment.   The slurry transport device according to claim 6, wherein the concentrating device is a thickener.

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