JP2019215300A - Selection method of pump for conveying slurry - Google Patents

Abstract

To newly provide a calculation method of a required conveyance force, in accurately measuring the viscosity of a slurry including, as particles, a metal-hydroxide or a metal oxide, and in selecting a pump used for conveyance of such slurry, and to provide a selection method of a pump for slurry conveyance of an appropriate scale on the basis of the calculation method.SOLUTION: A slurry includes: a liquid component; and a solid component formed of only the particles that have a grain size distribution in which 90% or more of particles have a grain size of 100 μm or less, and have a grain diameter of 1.4 mm or less. A pump is selected which outputs a required power of the pump calculated using the slurry viscosity calculated from the yield stress value of the slurry measured by a coaxial double cylindrical viscometer 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for transporting a slurry, a method for measuring the properties of the slurry to be transported, and a method for installing a pump for transporting the slurry.More specifically, the present invention relates to solid particles such as metal hydroxide or metal oxide. The present invention relates to a method for obtaining power required for transportation of a slurry containing the same, stabilizing the properties of the slurry from the viewpoint of transportation, and installing a pump suitable for transportation.

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 a leaching treatment method in which, for example, sulfuric acid is added to an ore slurry and leached at a high temperature and a 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 this HPAL method is applied, a neutralization step of adjusting the pH of the obtained leachate, and forming a neutralized precipitate slurry containing an impurity element such as iron and a purified mother liquor for nickel recovery, and A smelting method including supplying a hydrogen sulfide gas to the nickel recovery mother liquor and performing a sulfuration step of forming a mixed sulfide of nickel and cobalt and a poor solution is 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, and a nickel-cobalt mixed sulfide having a nickel grade of about 55 to 60% and a cobalt grade of about 3 to 6% is obtained. 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-described smelting process or the like is usually subjected to ore treatment and prepared to be charged into the smelting process to become an ore slurry, and the ore slurry is formed. And used in leaching and the like.
The ore treatment of the raw material ore includes, 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 stage.
First, in the crushing / classification stage, a raw material ore is crushed by a wet facility, and a classification process for removing oversized ore particles and contaminants is performed, and a coarse ore slurry composed of undersized ore particles and water is formed. It is manufactured (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 water removal increases the ore component contained in the ore slurry per the same transfer amount, which is effective in improving the operation efficiency of the entire plant.
However, in the conventional ore treatment as described above, the size of the ore particles fluctuates or the ore particles of various sizes coexist due to fluctuations in the particle size of the input raw ore and the degree of crushing in the crushing process. In some cases, and 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 slurry obtained may be too high.
Patent Literature 4 discloses a technique for measuring the viscosity. However, a viscometer suitable for a slurry such as a cement paste is disclosed, although it is generally difficult to measure the presence of a lump.

However, the slurry used in metal smelting contains heavy and hard particles of metal hydroxides and metal oxides, so that it was difficult to accurately measure the viscosity even with the viscometer of Patent Document 4.
Therefore, in order to transport a slurry containing various sizes and heavy hard particles, if the viscosity of the slurry cannot be measured accurately, a pump having an excessively large transport power is required. Therefore, in a smelter that processes a large amount of slurry, it is necessary to accurately measure the viscosity of the slurry and to suppress a variation in the viscosity of the slurry in order to provide a pump having a transporting power corresponding to the slurry to be transported. Was required.

JP 2005-350766 A JP 2009-173967 A JP-A-11-124640 JP-A-58-225330

  The present invention has been made in view of such circumstances, and accurately measures the viscosity of a slurry containing metal hydroxides and metal oxides as particles, and provides a pump for use in transporting such a slurry. In the selection, a new method for calculating the required transport capacity is provided, and a method for selecting an appropriate-scale pump for slurry transport is provided based on the calculated method.

  The present inventors have conducted intensive studies in order to achieve the above-described problem, and as a result, have found a simple viscometer suitable for measuring the viscosity of the slurry, and a slurry configuration in a form suitable for measuring the viscosity with the viscometer. Were found, and the accuracy of the formula for calculating the required transport force from the viscosity was improved, leading to the completion of the present invention.

  That is, the first invention of the present invention is a method for selecting a pump for transporting a slurry, which is a mixture of a solid component and a liquid component, wherein the slurry has a liquid component and a particle size distribution of 90% or more and 100 μm or less. And a solid component composed of only particles having a particle size of 1.4 mm or less having a particle size, and was calculated from the yield stress value of the slurry using a coaxial double cylindrical viscometer using the following equation (1). And selecting a pump that outputs the required power of the pump calculated using the viscosity of the slurry.

  The second invention of the present invention is a method for selecting a pump for transporting a slurry, wherein the solid component in the first invention is particles obtained by crushing and classifying nickel ore.

  A third invention of the present invention is a method for selecting a pump for transporting a slurry, wherein the slurry in the first and second inventions contains a flocculant.

  A fourth invention of the present invention is a method for transporting a nickel oxide ore slurry, wherein the slurry is transported using the pump selected by the method for selecting a pump according to the first to third inventions.

  According to the present invention, by accurately measuring the viscosity of a slurry containing metal hydroxides and metal oxides as particles, it is possible to calculate a predicted value that is very close to the actually measured value of the required transport force, and as a result, The introduction of a pump that can provide slurry transport capacity that matches the production scale and equipment enables efficient operation in terms of production cost and production efficiency, including equipment costs, and is industrially remarkable. It is effective.

It is a schematic diagram of a coaxial double cylindrical viscometer showing the principle of viscosity measurement of the present invention. It is a schematic diagram of the conventional Vane type viscometer used for the measurement of the yield stress. FIG. 3 is a process diagram of a method for hydrometallurgy of nickel oxide ore. It is a flowchart of the ore slurry manufacturing method.

Hereinafter, a specific embodiment 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.
1. 1. Measurement method of yield stress of slurry 2. Calculation method of transportation capacity 3. Verification method of yield stress Metal smelting method (wet smelting method of nickel oxide ore)

<1. Method for measuring yield stress of slurry>
The method for measuring the yield stress of a slurry according to the present embodiment is a method for measuring the yield stress of a slurry containing metal hydroxide or metal oxide as particles. Examples of the slurry include a slurry in which crushed ore is suspended in an aqueous solution and a slurry in which particles are precipitated by adding an alkali to the aqueous solution.

Specifically, the measurement of the yield stress of the slurry (evaluation product) according to the present embodiment is performed as follows.
In a viscometer (generally referred to as a coaxial double cylindrical viscometer) 10 having an outer cylinder 2 and an inner cylinder rotating body 1 having a measurement principle as shown in FIG. An external force is applied by a motor or the like so as to fill the cylindrical tube 2 and gradually increase the angular acceleration α [rad / s ² ] of the inner cylindrical rotating body 1. Actually, the viscous friction torque T [Nm] is applied from the filled slurry to the inner cylinder rotator 1 in a direction to cancel the rotational torque T ⁺ of the motor, and the state where the inner cylinder rotator 1 is stationary continues for a while. Thereafter, the slurry causes shear flow with a magnitude equal to or larger than a certain torque, and the inner cylinder rotating body 1 starts rotating. At the time when the shear flow starts, T = T ⁺ , and the shear stress at this time is the yield stress [Pa].

In such a coaxial double cylindrical viscometer 10, the viscous friction torque T due to the slurry is observed, and "shear stress S [Pa]" corresponding to the viscous friction resistance of the slurry is calculated by the following equation (2).
Therefore, the yield stress τ _y is obtained by the following equation (3). Note that _Rb is ［[m] of the outer diameter of the inner cylinder rotator 1 and h is the length [m] of the inner cylinder rotator.

<2. Calculation method of transportation capacity>
Next, in the method for calculating the transport force according to the present embodiment, the power required for transport is calculated as follows from the yield stress obtained by the above-described method for measuring the yield stress of the slurry.
Here, the ore slurry generally shows the properties of Bingham flow among non-Newtonian fluids, and the fluid having the properties of Bingham flow (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 "shear thinning effect" in which the viscosity decreases as the shear rate increases.

  In the present invention, in order to correctly consider the influence of the "shear thinning effect" due to the shear rate acting on the slurry in the pipe, the conversion equation shown in the following equation (4) is calculated from the yield stress measured by a coaxial double cylindrical viscometer. The apparent viscosity μ [Pa / s] of the ore slurry flowing in the pipe was calculated using the above equation.

Here, τ _y is the yield stress [Pa], τ _w is the liquid level shear stress [Pa], V is the average flow velocity in the pipe [m / s], D is the pipe inner diameter [m], and Le is the pipe equivalent length [m]. , ΔP represent friction pressure loss [Pa].
Next, the Reynolds number Re is determined by the following equation (5) 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 or turbulent state. In the case of a Newtonian fluid such as water, Re = 2000 to 2300 is generally a laminar turbulent threshold. However, in the case of Bingham fluid, this threshold value tends to be low, and the threshold value is set to Re = 1000 in the present invention.
Next, the pipe friction pressure loss ΔP _fric is calculated using “Darcy-Weissbach equation” of the following equation (6).

  Here, λ is called a friction coefficient. In the case of laminar flow, it is analytically obtained by λ = 64 / Re, but in the case of turbulent flow, it cannot be analytically obtained. Proposed. In the present invention, in the case of a turbulent flow, λ is obtained using “Colebrook's equation” shown in the following equation (7), 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 formula and procedure.

Next, a 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 (8), where P _all is the required pressure, ΔP _{Fric is the} friction pressure loss, ΔP _{h is} the head term, and ΔP _V is the speed term.

Here, ΔP _h and ΔP _V are respectively obtained by the following equation (9). Here, g is the gravitational acceleration [m / s ² ], and ΔH is the head [m].

Therefore, the necessary shaft power P _ax [W] of the pump is calculated by the following equation (10) 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 (11).

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.

Next, conventional measurement of yield stress will be described.
In the coaxial double-cylindrical viscometer 10 shown in FIG. 1, a vane-type rotating body 3 called a Vane type as shown in FIG. The same operation as in the case of using the viscometer shown in FIG. 1 is performed, and the “shear stress” is calculated from the obtained viscous friction torque according to the following equation (12), and “τ” is obtained from the above equation (4). _The yield stress is determined as “ _y = S ₀ ”. In FIG. 2, B is the total width [m] of the rotating body (blades), L is the total length [m] of the rotating body (blades), and T ⁺ is the rotating torque [Nm]. At the time when the shear flow starts, the viscous friction torque T = T ⁺ .

When converting the yield stress value measured by a Vane-type viscometer into the viscosity μ required for determining the frictional pressure loss and the power consumption of the pump, the following approximate calculation is performed for the influence of the shearing effect due to the shear rate. Do. In this case, the ore slurry is assumed to be a Newtonian fluid, and the pipe inner wall surface shear rate γ _w [1 / s] is calculated by the following equation (13).

Furthermore, in general, the shear stress increases linearly with the shear rate in the first order linearly for Newtonian fluids and non-linearly for non-Newtonian fluids. However, in the conventional method, the shear stress is constant regardless of the shear rate (yield stress value). ), The apparent viscosity μ _a is obtained by the approximate expression of the following expression (14), and the calculated value P _{m of the} power consumption of the pump is similarly calculated from the μ _a and the expressions (5) to (11). calculate.

<3. Verification method of yield stress>
In the verification method of the yield stress, the value calculated by the above-described method of calculating the transport force is compared with the actually measured value of the transport force actually consumed by driving the pump.
If these two values are close to each other (for example, if the difference is within 20%, it is assumed to be close), it is determined that the method of measuring the viscosity of the slurry is appropriate and the method of calculating the transport force is appropriate.

  If it is determined to be appropriate, the necessary parameters are calculated by replacing the calculation parameters in consideration of the flow rate, height difference, pipe length, pipe bending degree, etc. assumed at the factory. An industrial pump capable of exerting the calculated transportation capacity can be obtained and installed. If an industrial pump has already been installed, it can be replaced with a necessary and sufficient one (for example, 100 to 120% of the calculated capacity), and the removed existing product can be re-used for more appropriate use. The effect is great because it can be arranged.

  If it is not determined to be appropriate, change the shape of the rotating body used in the method of measuring the viscosity of the slurry and try again.However, as the shape of the rotating body, for example, provide a paddle-shaped blade and the difference when comparing the transport force Change the size of the blade so that it becomes smaller. At this time, the blades can be inclined to change the inclination angle.

  As described above, the comparison can be performed using a small test pump, and after confirming that the comparison accuracy is high, an expensive industrial pump can be obtained. No need to buy again.

  In addition, as a factor that causes an error in the viscosity and an error in the transport force, there is variation in the distribution of the solid particles in the slurry. Therefore, in order to stabilize the dispersion of the distribution of the solid particles, a coagulant may be added to the slurry. In the slurry to which the coagulant is added, the solid particles are appropriately agglomerated to form secondary particles, and the particle diameter of the secondary particles is substantially constant, so that the viscosity is stable and the necessary transport force has a constant value. Take.

<4. Metal smelting method (wet smelting method of nickel oxide ore)>
Therefore, next, a description will be given of a hydrometallurgical method for recovering nickel and cobalt from nickel oxide ore by HPAL using ore slurry for selecting the pump for transporting the slurry according to the present invention.

  FIG. 3 shows an example of a process diagram of a wet smelting method of a nickel oxide ore by a high-temperature pressurized acid leaching method. As shown in FIG. 3, 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 hydrate slurry and a sulfurization step S25 in which hydrogen sulfide gas is blown into sulfuric acid as a mother liquor to carry out 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 step 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, in the ore slurry manufacturing step S21 (S1 to S3) in the metal smelting method according to the present embodiment shown in FIG. 4, the raw ore is crushed, classified at a predetermined classification point, and oversized. Crushing / classifying step S1 of removing coarse ore particles of undersized ore particles and water to remove coarse ore particles, and a particle size measuring step of measuring the particle size of the coarse ore slurry obtained in the crushing / classifying step S2 and the ore slurry concentration step S3 of charging the coarse ore slurry into the solid-liquid separator and separating and removing the water contained in the coarse ore slurry to concentrate the ore components, thereby obtaining the predetermined 90% of the present invention. An ore slurry having a solid component and a liquid component composed only of particles having a particle size distribution of not more than 100% and not more than 100 mm is prepared.

  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 the ore slurry production process S21, an ore slurry in which the 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 process.

  The slurry concentration (solid component concentration) of the ore slurry produced in the ore slurry production step S21 is not particularly limited, but is preferably adjusted to be 15 to 45% by mass.

(Leaching process)
The ore slurry obtained in the ore slurry production step S21 is transported to the leaching step S22 via the pump according to the present invention, and in the leaching step S22, sulfuric acid is added, and a stirring treatment is performed at a temperature of 220 to 280 ° C. A leaching slurry comprising a leaching solution and a leaching residue is formed. In the leaching step S22, for example, a high-temperature pressurized container (autoclave) is used.

  Specifically, in the leaching step S22, a leaching reaction and a high-temperature hydrolysis reaction represented by the following formulas (A) to (E) occur, and leaching as a sulfate such as nickel, cobalt, or the like, Immobilization of iron 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 excessive amount is used such that iron in the ore is leached. For example, 300 to 400 kg per ton of ore. If the added amount of sulfuric acid 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 multi-stage 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 a countercurrent is brought into contact with a cleaning liquid containing no nickel. . 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 is 4 or less, while suppressing the oxidation of the leachate separated in the solid-liquid separation step S23. A neutralized slurry containing iron is formed. 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 leachate exceeds 4, the generation of nickel hydroxide increases.

  Further, in the neutralization step S24, when removing the trivalent iron ions remaining in the solution, it is preferable not to oxidize the iron ions existing as divalent 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 generation of the neutralized precipitate slurry due to the removal of divalent iron. That is, it is possible to suppress the 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, nickel hydroxide generated by a local reaction on the surface of the neutralized precipitate is obtained by repeating the neutralized precipitate slurry to the solid-liquid separation step S23 operated at a lower pH condition than the neutralization step S24. Can be dissolved, and water attached to the neutralized precipitate 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 about 50 to 80 ° C. 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 device material decreases.

(Sulfurization process)
In the sulfurizing step S25, a hydrogen sulfide gas is blown into the aqueous sulfuric acid solution, which is the mother liquor for nickel recovery, obtained in the neutralizing step S24 to cause a sulfurizing 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 sulfides. 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 forming 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 small amount of impurities and a poor solution whose 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 that precipitates as a substance, and to reduce the recovery loss of nickel.

  The addition amount of the nickel sulfide serving as a seed crystal is preferably an addition amount equivalent to 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.

  The nickel sulfide to be 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, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

After mixing the nickel oxide ore of the production area A with water to form a slurry, the contained lump having a particle diameter of 1.4 mm or more was removed to prepare a slurry A as a test material. The solid component concentration of the slurry A was 42% by mass. The viscosity of the obtained slurry A was measured using a coaxial double cylindrical viscometer manufactured by Rheosys. Using the obtained apparent viscosity, to obtain a calculated value P _m of the yield stress of the slurry A from (4) to (10),
In the calculation, the absolute roughness ε of the steel pipe was assumed to be 0.457 mm. Further, the margin ratio e [%] set when designing the pump was set to e = 0, and the conduction efficiency η _{2 of the} energy transmitted from the motor to the shaft was set to 95%.

The calculated value of the calculated value _{P m} power values was calculated to 68Kw.
When a pump was selected based on the present invention and actually operated, the required power (actually measured value P _r ) was 61 kw, and a result that was very consistent with the predicted value was obtained.

The same operation as in Example 1 was performed except that the nickel oxide ore of the production area B was used.
Calculated P _m power values required for the pump was calculated to 55kW. When a pump was selected based on this method and actually operated, the required power (actually measured value P _r ) was 62 kw, which was in good agreement with the calculated value.

  The same operation as in Example 1 was performed, except that a coagulant was added for concentration before collecting a slurry sample. The solid component concentration of the slurry used as the test material was 43% by mass. The power required for the pump was calculated to be 57 kw. When a pump was selected based on this method and actually operated, the required power was 63 kW, and a very good agreement with the calculated value was obtained.

(Comparative Example 1)
The apparent stress was measured using a nickel oxide ore from the production area A, and the apparent viscosity was measured using a viscometer called Vane type (conventional type) for the measurement of the viscosity, and the yield stress was calculated.
The pump power calculated by the method of Comparative Example 1 was 117 kW. When the actual pump power was investigated, it was 61 kW, and the value of the power was far apart.
Table 1 summarizes the results of the above examples.

(Reference Example 1)
A slurry B was obtained by adding particles having a particle size of more than 1.4 mm to the slurry A of Example 1 and having a particle size distribution in which 90% or more of the solid components of the slurry were 100 μm or less. The viscosity was measured, the pump power was calculated, and the measured value was compared under the same conditions as in Example 1 except that the slurry B was used as the test material. As a result, the calculated value and the measured value were not as good as those of Comparative Example 1. However, the deviation was larger than in Examples 1 to 3.

  ADVANTAGE OF THE INVENTION According to this invention, the calculation method which can measure the viscosity of a slurry accurately and can calculate required transportation force can be provided. According to such a calculation method, the slurry can be transferred by the pump having the minimum necessary transport force, and efficient operation can be performed. In particular, it is suitable for ore slurries, neutralized slurries, and slurries containing metal hydroxides and metal oxides as particles, which are widely handled in smelters.

DESCRIPTION OF SYMBOLS 1 Inner cylinder rotating body 2 Outer cylinder tube 3 Vane blade-shaped rotating body 10 Coaxial double cylindrical viscometer Rb Inner cylinder radius of coaxial double cylindrical viscometer Rc Outer cylinder radius of coaxial double cylindrical viscometer h Height of coaxial double cylindrical viscometer B Total width of rotor (vane) of Vane viscometer L Total length (height) of rotor (vane) of Vane viscometer
Rotating torque of T ⁺ Vane type viscometer

Claims (4)

A method for selecting a pump for transporting slurry,
The slurry is composed of a liquid component and a solid component composed of only particles having a particle size distribution of 90% or more and 100 μm or less and having a particle size of 1.4 mm or less,
It is necessary to select a pump that outputs the necessary power of the pump calculated using the viscosity of the slurry calculated using the following equation (1) from the yield stress value of the slurry measured using a coaxial double cylindrical viscometer. How to select a pump that transports the characteristic slurry.

  The method for selecting a pump for transporting slurry according to claim 1, wherein the solid component is particles obtained by crushing and classifying nickel ore.   The method for selecting a pump for transporting a slurry according to claim 1 or 2, wherein the slurry contains a flocculant.   A method for transporting a nickel oxide ore slurry, comprising transporting a slurry using a pump selected by the method for selecting a pump according to claim 1.

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