CN214512807U - Crystallization system for producing nickel sulfate by continuous method - Google Patents

Abstract

The utility model belongs to the technical field of sulfate industrial production, in particular to a crystallization system for producing nickel sulfate by a continuous method. The utility model relates to a crystallization system for producing nickel sulfate by a continuous method, which comprises a crystallizer, a fine grain eliminator, a feed pump, a heat exchanger, a discharge pump, a thickener and a centrifuge. The utility model discloses a crystallization system of continuous process production nickel sulfate guarantees that nickel sulfate solution forms the homogeneous supersaturation everywhere in the crystallizer to the realization is prepared out the even and granularity of particle size distribution and can reach the nickel sulfate product more than 800 mu m. Compared with the traditional intermittent crystallization mode, the crystallization system adopts a continuous crystallization mode, and the production capacity is enhanced.

Description

Crystallization system for producing nickel sulfate by continuous method

Technical Field

The utility model belongs to the technical field of sulfate industrial production, in particular to a crystallization system for producing nickel sulfate by a continuous method.

Background

The nickel sulfate is used as an important chemical raw material, has wide application in the fields of civil use, construction, aerospace equipment, national defense industry and the like, and is particularly applied to the aspects of electroplating, chemical plating, aluminum coloring, battery materials, catalysts and the like.

The preparation of nickel sulfate is generally carried out by single effect evaporation or multiple effect evaporation concentration of dilute solution to a certain proportion, and then a nickel sulfate product is obtained by using an intermittent crystallization mode. The intermittent crystallization operation is usually to add the nickel sulfate solution into the crystallization kettle once, and then to perform single kettle crystallization by adjusting the process parameter conditions of the crystallization kettle, such as cooling rate, stirring frequency, seed crystal addition, crystallization time, and the like, so as to obtain the nickel sulfate product with the target particle size. The process for producing the nickel sulfate crystal by the method has the following defects: 1. single-kettle crystallization is adopted, so that more process parameters are controlled, and the batch uniformity of the product is low; 2. the batch operation is completed, and the production efficiency is low; 3. the investment cost is high, and the occupied area is large; 4. the energy consumption in the evaporation and concentration process is large.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provide a crystallization system for producing nickel sulfate by a continuous method.

In order to achieve the purpose, the utility model relates to a crystallization system for producing nickel sulfate by a continuous method, which comprises a crystallizer, a fine grain eliminator, a feeding pump, a heat exchanger, a discharging pump, a thickener and a centrifuge; the crystallizer comprises an upper cylinder, a middle cylinder and a lower cylinder, wherein the upper cylinder is provided with a steam outlet, and the steam outlet is connected with the heat exchanger; the middle part of the middle cylinder body is provided with a clear liquid external circulation outlet, a straight cylinder baffle plate is arranged in the middle cylinder body, a guide cylinder is arranged in the straight cylinder baffle plate, a stirrer is arranged in the guide cylinder, and the lower cylinder body is provided with a feed inlet and a discharge outlet; the clear liquid external circulation outlet is connected with a feeding pump, the feeding pump is connected with a fine grain eliminator, the fine grain eliminator is connected with a feeding port on the lower cylinder body, and the feeding port is connected with the guide cylinder through a feeding pipe; the discharge port of the crystallizer is connected with a discharge pump, the discharge pump is connected with a thickener, and the thickener is connected with a centrifugal machine; wherein the guide cylinder, the straight cylinder baffle plate and the stirrer form an internal circulation passage of the crystallization system, and the clear liquid external circulation outlet, the fine grain eliminator, the feed pump and the feed pipe form an external circulation passage of the crystallization system; the guide cylinder is a variable-diameter guide cylinder, the variable-diameter guide cylinder consists of a section of straight cylinder and a section of variable-diameter cylinder body, the height of the straight cylinder is 0.25-0.5 times of that of the variable-diameter cylinder body, and the maximum diameter of the variable-diameter cylinder body is 1-2 times of that of the variable-diameter cylinder body; the stirrer is a push type stirring paddle and extends into the guide cylinder from the bottom of the crystallizer; the feed inlet is connected with the inlet pipe, and the inlet pipe is 15 ~ 30 inclinations with horizontal position, and the barrel sets up 2 feed inlets down, and feed inlet and the inlet pipe that links to each other set up with crystallizer axial symmetry.

Preferably, the middle part of the middle cylinder body is provided with 2-4 clear liquid external circulation outlets.

As preferred, the lower barrel sets up 2 ~ 5 discharge gates, and wherein 1 ~ 2 discharge gates set up barrel bottom under, and 2 ~ 3 discharge gates set up the barrel side under, can't continue to produce after avoiding bottom discharge gate putty.

The utility model discloses the during operation: concentrating the dilute nickel sulfate solution in a multi-effect evaporation mode until the dilute nickel sulfate solution is nearly saturated, and feeding the nearly saturated nickel sulfate solution into a guide shell of a crystallizer through a feeding pipe; the guide cylinder, the straight cylinder baffle and the stirrer form an internal circulation passage of the crystallization system, and the straight cylinder baffle separates the guide flow zone from the crystal settling zone so as to control the size of crystal particles; under the action of stirring, the nickel sulfate solution moves upwards in the guide shell and downwards outside the guide shell, the high-temperature nickel sulfate solution close to saturation directly contacts with the low-temperature nickel sulfate solution in the crystallizer to mix, exchange heat and transfer mass, the temperature of the fed nickel sulfate solution is rapidly reduced, and meanwhile, the nickel sulfate solution at each position in the crystallizer forms uniform supersaturation. The clear liquid external circulation outlet, the fine crystal eliminator, the feeding pump and the feeding pipe form an external circulation passage of a crystallization system, nickel sulfate clear liquid in the crystallizer enters the fine crystal eliminator through the clear liquid external circulation outlet in the crystallization process, heat exchange is carried out in the fine crystal eliminator to heat, dissolve and eliminate excessive fine crystals in the nickel sulfate clear liquid, and the nickel sulfate clear liquid after the fine crystals are eliminated is conveyed into a guide cylinder of the crystallizer again through the feeding pipe; evaporating and crystallizing the nickel sulfate solution under the vacuum condition of a crystallizer to obtain nickel sulfate crystal slurry, discharging, and performing centrifugal filtration and low-temperature drying to obtain a nickel sulfate product; and the secondary steam from the evaporation system is used for preheating the dilute nickel sulfate solution after being pressurized and heated.

The utility model discloses a crystallization system of continuous process production nickel sulfate guarantees that nickel sulfate solution forms the homogeneous supersaturation everywhere in the crystallizer to the realization is prepared out the even and granularity of particle size distribution and can reach the nickel sulfate product more than 800 mu m. Compared with the traditional intermittent crystallization mode, the crystallization system adopts a continuous crystallization mode, and the production capacity is enhanced. Has the following beneficial effects:

1. the feed inlet is connected with the inlet pipe, and the inlet pipe is 15 ~ 30 inclinations with horizontal position, and the lower barrel sets up 2 feed inlets, and feed inlet and the inlet pipe that links to each other set up with crystallizer medial symmetry. The high-temperature material and the low-temperature material directly enter the guide cylinder along the inclination angle, and the high-temperature material and the low-temperature material are rapidly mixed for heat and mass transfer under the stirring effect in the guide cylinder, so that the heat and mass transfer time is shortened.

2. The crystallizer adopts the reducing guide shell, the flow velocity of the solution at the top end of the guide shell is mild, splashing can be prevented, scaling on the surface of the crystallizer is reduced, and the production capacity is improved; the solution flow rate is mild, the retention time of crystal slurry near a gas-liquid interface can be prolonged, the supersaturation degree of the interface is eliminated, a large amount of fine crystals are avoided, and the growth of the crystals is facilitated.

3. The crystallization system is provided with an internal circulation channel and an external circulation channel, and the bottom stirring of the internal circulation channel promotes the rapid mixing, heat exchange and mass transfer of the solution in the crystallizer, so that the supersaturation degree of the nickel sulfate solution at each position in the crystallizer is uniform. And a fine grain eliminator is arranged in the external circulation channel and used for eliminating excessive crystallization and ensuring that a large amount of fine grains cannot be kept in the system. The above design can ensure the prepared nickel sulfate crystal to have uniform particle size distribution and the particle size of the crystal can reach more than 800 μm.

4. The crystallization system is a crystal slurry circulating type continuous crystallization device, can realize continuous feeding crystallization, is provided with a plurality of discharge ports, has high production strength, and is suitable for large-scale industrial production. The continuous crystallization system has small occupied area which is only 20-30% of the batch crystallization process, and the investment amount is only 60-70% of the investment of batch crystallization equipment. The secondary steam evaporated is used for preheating the dilute nickel sulfate solution, so that the energy utilization rate is improved, and the energy consumption in the production process is reduced by 10-20%.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the structure of a crystallizer;

in the figure: 1. the device comprises a crystallizer, 2 parts of a fine grain eliminator, 3 parts of a feeding pump, 4 parts of a heat exchanger, 5 parts of a discharging pump, 6 parts of a thickener, 7 parts of a centrifuge, 8 parts of a steam outlet, 9 parts of a middle cylinder, 10 parts of a clear liquid external circulation outlet, 11 parts of a lower cylinder, 12 parts of a feeding pipe, 13 parts of a feeding hole, 14 parts of a stirrer, 15 parts of an upper cylinder, 16 parts of a guide cylinder, 17 parts of a straight cylinder baffle and 18 parts of a discharging hole.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the objects of the present invention, the following detailed description of the embodiments, structures, features and effects according to the present invention will be made with reference to the accompanying drawings and preferred embodiments.

As shown in fig. 1 and fig. 2, the crystallization system for continuously producing nickel sulfate described in this embodiment includes a crystallizer 1, a fine crystal eliminator 2, a feed pump 3, a heat exchanger 4, a discharge pump 5, a thickener 6 and a centrifuge 7; the crystallizer comprises an upper cylinder body 15, a middle cylinder body 9 and a lower cylinder body 11, wherein the upper cylinder body is provided with a steam outlet 8, and the steam outlet is connected with a heat exchanger; 2-4 clear liquid external circulation outlets 10 are arranged in the middle of the middle cylinder body, a straight cylinder baffle 17 is arranged in the middle cylinder body, a variable-diameter guide cylinder 16 is arranged in the straight cylinder baffle, the variable-diameter guide cylinder consists of a section of straight cylinder and a section of variable-diameter cylinder body, the height of the straight cylinder is 0.25-0.5 times of the height of the variable-diameter cylinder body, the maximum diameter of the variable-diameter cylinder body is 1-2 times of the minimum diameter of the variable-diameter cylinder body, a stirrer 14 is arranged in the guide cylinder, and the stirrer is a push type stirring paddle and extends into the guide cylinder from the bottom of the crystallizer; the lower barrel is provided with 2 feed inlets 13, the feed inlets are connected with the guide shell through feed pipes 12, the feed pipes and the horizontal position form an inclination angle of 15-30 degrees, and the feed inlets and the feed pipes connected with the feed inlets are symmetrically arranged by the central axis of the crystallizer; the lower cylinder is provided with 2-5 discharge ports 18, wherein 1-2 discharge ports are formed in the bottom of the lower cylinder, and 2-3 discharge ports are formed in the side face of the lower cylinder; the clear liquid external circulation outlet is connected with a feeding pump, the feeding pump is connected with a fine grain eliminator, and the fine grain eliminator is connected with a feeding hole on the lower cylinder body; the discharge port of the crystallizer is connected with a discharge pump, the discharge pump is connected with a thickener, and the thickener is connected with a centrifugal machine; wherein the guide cylinder, the straight cylinder baffle plate and the stirrer form an internal circulation passage of the crystallization system, and the clear liquid external circulation outlet, the fine grain eliminator, the feeding pump and the feeding pipe form an external circulation passage of the crystallization system.

The utility model discloses the during operation: the nearly saturated nickel sulfate solution enters the feed pipe 12 from the feed inlet 13 of the lower cylinder 11, enters the guide shell 16 of the crystallizer through the feed pipe 12, under the action of the propeller stirrer 14, the nickel sulfate solution moves upwards in the guide shell 16 and downwards outside the guide shell 16, large crystal particles are settled to the discharge outlet 18 under the action of gravity, and small crystal particles return to the guide shell 16 again due to the turbulent motion of fluid for circulating crystallization and slowly grow up; the straight cylinder baffle 17 separates the flow guide area from the crystal settling area, the flow guide area is arranged inside the straight cylinder baffle, and the crystal settling area is arranged outside the straight cylinder baffle; the extremely small particles flow out of the clear liquid external circulation outlet 10 along with the nickel sulfate clear liquid in the crystallizer under the turbulence, meanwhile, the extremely small particles are heated and dissolved at the fine grain eliminator 2, and the nickel sulfate clear liquid after the fine grain elimination enters the crystallizer again from the feeding hole 13; the large-particle crystals are sent to a centrifuge 7 from a discharge port 18 through a discharge pump 5 for solid-liquid separation, and then enter a fluidized bed for drying, so as to obtain a nickel sulfate product with uniform particle size distribution and particle size of more than 800 mu m.

The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above description, and although the present invention has been disclosed by the preferred embodiment, it is not limited to the present invention, and any person skilled in the art can make modifications or changes equivalent to the equivalent embodiments by utilizing the above disclosed technical contents without departing from the technical scope of the present invention, but all the modifications, changes and changes of the technical spirit of the present invention made to the above embodiments are also within the scope of the technical solution of the present invention.

Claims (3)

1. A crystallization system for producing nickel sulfate by a continuous method, which is characterized in that: comprises a crystallizer, a fine grain eliminator, a feeding pump, a heat exchanger, a discharging pump, a thickener and a centrifuge; the crystallizer comprises an upper cylinder, a middle cylinder and a lower cylinder, wherein the upper cylinder is provided with a steam outlet, and the steam outlet is connected with the heat exchanger; the middle part of the middle cylinder body is provided with a clear liquid external circulation outlet, a straight cylinder baffle plate is arranged in the middle cylinder body, a guide cylinder is arranged in the straight cylinder baffle plate, a stirrer is arranged in the guide cylinder, and the lower cylinder body is provided with a feed inlet and a discharge outlet; the clear liquid external circulation outlet is connected with a feeding pump, the feeding pump is connected with a fine grain eliminator, the fine grain eliminator is connected with a feeding port on the lower cylinder body, and the feeding port is connected with the guide cylinder through a feeding pipe; the discharge port of the crystallizer is connected with a discharge pump, the discharge pump is connected with a thickener, and the thickener is connected with a centrifugal machine; the guide cylinder is a variable-diameter guide cylinder, the variable-diameter guide cylinder consists of a section of straight cylinder and a section of variable-diameter cylinder body, the height of the straight cylinder is 0.25-0.5 times of that of the variable-diameter cylinder body, and the maximum diameter of the variable-diameter cylinder body is 1-2 times of that of the variable-diameter cylinder body; the stirrer is a push type stirring paddle and extends into the guide cylinder from the bottom of the crystallizer; the feed inlet is connected with the inlet pipe, and the inlet pipe is 15 ~ 30 inclinations with horizontal position, and the barrel sets up 2 feed inlets down, and feed inlet and the inlet pipe that links to each other set up with crystallizer axial symmetry.

2. The crystallization system for the continuous production of nickel sulfate according to claim 1, wherein: the middle part of the middle cylinder body is provided with 2-4 clear liquid external circulation outlets.

3. The crystallization system for the continuous production of nickel sulfate according to claim 1, wherein: the barrel sets up 2 ~ 5 discharge gates down, and wherein 1 ~ 2 discharge gates set up barrel bottom down, and 2 ~ 3 discharge gates set up barrel side down.

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