Apparatus and method for enhanced leaching of high indium content scrap

Abstract

The application discloses a kind of reinforced leaching high indium-containing waste device and method, belong to the technical field of recycling valuable metal.The application solves the problem that high indium-containing waste is easy to sink bottom by changing the stirring system of leaching indium, comprising the following steps: I.high indium-containing waste is transported to chemical reactor, and hydrochloric acid is added according to liquid-solid ratio;II.water bath system is used to heat the chemical reactor, open the nonlinear stirring system, and output function to frequency converter through function generator, realize the control of nonlinear stirring system, while opening the air injection system;III.after leaching is completed, water bath system, nonlinear stirring system and air injection system are closed, and leaching solution is separated from leaching residue.The leaching rate of indium in the stirring system of the application can reach 92%-98%, the power range is 0.001w-0.00174w, and the energy consumption is reduced by 50%-65%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of recycling valuable metals, and more particularly to a device and method for mechanically stirring and strengthening leaching of high-indium-containing waste. BACKGROUND

[0002] Indium is a rare metal, and there is no pure mineral, but it exists in the form of associated ore in other metal sulfide ore, mainly in sphalerite, hematite, galena, etc. The concentration of indium is between 10-20 mg / kg, and its compounds are widely used in the electronic industry, semiconductor industry, etc. Indium tin oxide (ITO) has excellent display performance, so it is widely used in displays of various electronic devices such as televisions, telephones, and notebook computers. At present, the utilization rate of ITO target on the sputtering layer is very low, and the proportion of waste target is as high as 70% or more, and the content of indium is more than 75%. The content of indium in discarded liquid crystal display (LCD) is more than 0.03%, while the content of indium in ore is only 0.002%. ITO waste material can still be obtained through stripping and pre-enrichment in discarded LCD, which has very high recycling value. Since the content of indium in high-indium-containing waste is much higher than that in ore, compared with ore, recycling indium from high-indium-containing waste is of great significance to alleviate the contradiction between supply and demand of indium resources in industrial production and life, and will promote the sustainable development of the indium industry.

[0003] At present, the research on resource utilization of indium in ITO waste target mainly includes fire method and wet method. The methods for recovering indium from ITO target by fire method mainly include thermal reduction method and chlorination method, and the energy consumption of the fire method for recovering indium is high, and it will produce waste gas and waste water to cause environmental pollution. Compared with the fire method for recovering indium, the wet method has the advantages of lower cost, lower energy consumption, less sensitive to equipment precision, no harmful smoke, etc., and has strong industrial application prospect. The key step of wet method for recovering indium is to leach indium in high-indium-containing waste. In the traditional leaching process of indium, the stirring system generally uses a flat-bottomed, baffle-free chemical reactor with radial paddles, and the stirring paddle is controlled at a constant speed. The uniform speed stirring leaching system has large mixing isolation zone, less effective collision between particles, and high energy consumption. In the uniform speed stirring mixing process, the initial stage is a strong mixing period, and the flow field has not reached a stable state. In the later stage, the flow field reaches a stable state, and a ring-shaped large nest is formed at the upper and lower ends of the stirring paddle, and finally an isolated mixing isolation zone is formed. In the high-indium-containing waste stirring leaching system, due to the large density of high-indium-containing waste, particle accumulation phenomenon is easily formed at the bottom of the chemical reactor.

[0004] Chinese patent CN 116196871 A discloses a nonlinear variable-speed double-layer glass stirred reactor. This invention reduces energy consumption during stirring, improves production efficiency, and achieves energy conservation and emission reduction. However, this invention does not involve bottom-jetting stirring, which easily leads to particle accumulation at the bottom of the stirred reactor. Chinese patent CN 204544108U discloses a stirring shaft with nonlinear stirring blades, which can achieve better mixing results. This invention improves the blades, and the stirring shaft in the reactor uses a uniform-speed stirring motion, but it is less effective and consumes more energy than variable-speed stirring. Chinese patent CN 115541695A discloses a nonlinear jet stirring system and method based on tomographic imaging measurement. It uses nonlinear jetting to stir the gas-liquid mixture in the stirrer, but this invention does not add mechanical stirring, resulting in poor mixing uniformity during solid-liquid mixing. Furthermore, none of the above patents have been applied to high-indium waste leaching systems.

[0005] Therefore, how to break down the mixing isolation zone and improve the mixing performance of the stirring system by changing the structure of the chemical reactor, the shape of the impeller, the rotation mode of the stirring impeller, and adding bottom spraying is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, in order to solve the problems of low indium leaching efficiency and high energy consumption in traditional processes, this invention seeks a new nonlinear enhanced stirring leaching system to reduce the mixing isolation zone in the stirring system, improve the indium leaching rate, and reduce energy consumption.

[0007] To achieve the above objectives, the present invention provides a method for enhancing the leaching of waste with high indium content, the specific steps of which are as follows:

[0008] I. The high-indium-content waste is transported to a chemical reactor, and hydrochloric acid is added according to the liquid-solid ratio;

[0009] II. The chemical reactor is heated using a water bath system, the nonlinear stirring system is turned on, and the function is output to the frequency converter through the function generator to control the nonlinear stirring system. At the same time, the jet system is turned on.

[0010] III. After leaching is complete, shut down the water bath system, nonlinear stirring system and jet system to separate the leachate from the leaching residue.

[0011] Preferably, the high indium-containing waste material described in step I is fed to the chemical reactor after being crushed and ball-milled, with a ball milling particle size of 200-400 mesh; the liquid-to-solid ratio is 10:1-30:1; and the concentration of hydrochloric acid is 3-6 mol / L.

[0012] Furthermore, the hydrochloric acid used is industrial hydrochloric acid with a concentration of 36%-38% as per national standards.

[0013] Preferably, the heating temperature of the water bath system in step II is 50-85℃.

[0014] Preferably, the function output by the function generator in step II is a trapezoidal function, a half-wave sine function or an H variable speed function; the rotating speed of the nonlinear stirring system is 0-150rpm, and the variable speed period is 0-20s; the speed of the air injection system is 0.01-0.05m / s.

[0015] The beneficial effects of the above technical solution are that the air injection inlet is arranged at the bottom of the chemical reactor, the air injection speed ranges from 0.01m / s to 0.05m / s, the powder material particle sinking bottom phenomenon is improved, the particle contact area with the hydrochloric acid system is increased, and thus the leaching efficiency is improved.

[0016] Preferably, the leaching time in step III is 120-150min.

[0017] Further, in order to achieve the above-mentioned purpose, the application provides a device for strengthening leaching of high-indium-containing waste materials, which comprises a support, a nonlinear stirring system, a water bath system, a chemical reactor and an air injection system.

[0018] The stirring part of the nonlinear stirring system extends into the chemical reactor from the center thereof, and the nonlinear stirring system is fixed on the support.

[0019] The heating part of the water bath system submerges the middle and lower parts of the chemical reactor.

[0020] The air injection system is connected with the bottom of the chemical reactor.

[0021] Preferably, the paddle of the stirring part is an inclined paddle with an inclination of 45°; the top of the chemical reactor is provided with a baffle, the bottom is a round bottom, and an interface connected with the air injection system is arranged.

[0022] The beneficial effects of the above technical solution are that the stirring system adopts an inclined paddle, and the inclined paddle stirring system is a combination of axial flow and radial flow. Not only the solid-liquid mixing capacity can be improved, but also the stirring power can be reduced to reduce energy consumption; the baffle is added in the stirring system, and during the stirring process, part of the fluid moves upward and part of the fluid moves downward after moving to the vicinity of the baffle, thereby improving the axial mixing capacity of the reactor.

[0023] Preferably, the nonlinear stirring system comprises a frequency converter, a function generator, a three-phase asynchronous motor and a condensation reflux device.

[0024] Wherein, the frequency converter is fixed on the support, and one end of the frequency converter is connected with the function generator, and the other end is connected with the three-phase asynchronous motor; the three-phase asynchronous motor is located directly above the chemical reactor; the condensation reflux device is used for condensation of the chemical reactor; the three-phase asynchronous motor controls the stirring part.

[0025] Via the technical solution, compared with the prior art, the application provides a nonlinear reinforced stirring leaching system, and has the following beneficial effects:

[0026] In the variable-speed stirring process of the application, the fluid is continuously stretched and folded, which can effectively break the mixing isolation zone in the uniform stirring process, improve the axial mixing capacity of the solid-liquid two-phase, increase the effective collision frequency between reactants, and improve the leaching rate of indium. The bottom blowing can effectively improve the phenomenon of particle sinking to the bottom, increase the contact area of the powder material and the hydrochloric acid system, and thus improve the leaching rate of indium.

[0027] In the application, under the driving of the paddle, the fluid has an acceleration and deceleration process, and the fluid is continuously stretched and folded to form a more turbulent flow field. The mixing isolation zone is reduced, the effective collision frequency of indium oxide and hydrochloric acid solution is increased, and finally the leaching rate of indium in high-indium-containing waste material in the H variable-speed function is improved by more than 5% compared with the traditional uniform stirring system. Under the premise of H variable speed, the bottom blowing is added to improve the solid-liquid mixing capacity of the stirring system, improve the phenomenon of particle sinking to the bottom, increase the contact area of high-indium-containing waste material and hydrochloric acid, and further improve the leaching rate. The power consumption of the stirring shaft in the H variable-speed stirring process is reduced by 60%-63% compared with the uniform stirring process, and the energy-saving effect is good.

[0028] The leaching rate of indium in the traditional uniform stirring system can be up to 91%, and the leaching rate of indium in the trapezoidal function variable-speed stirring system, the half-wave variable-speed stirring system, the H variable-speed stirring system and the H variable-speed stirring and blowing stirring system can be up to 92%-98%, the power range is 0.001w-0.00174, and the energy consumption is reduced by 50%-65%. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the application, and those skilled in the art can obtain other drawings according to the provided drawings without creating any inventive labor.

[0030] Figure 1 The drawing is a principle diagram of the nonlinear stirring leaching system provided by the application.

[0031] In the figure: 1, support; 2, three-phase asynchronous motor; 3, condenser tube; 4, stirring paddle; 5, chemical reactor; 6, jet pipe; 7, constant temperature water bath; 8, thermometer; 9, frequency converter; 10, function generator.

[0032] Figure 2 The drawing is a function diagram of different stirring modes. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] The principle of the nonlinear intensified stirring leaching system of the present application is as follows:

[0035] In the nonlinear variable-speed stirring system, the fluid is continuously stretched and folded in the acceleration and deceleration stages, breaking the pseudo-uniform state of the traditional uniform stirring system. The high-indium-content powder material and the hydrochloric acid system are mixed more uniformly, the effective collision frequency of the reaction system is increased, and the leaching efficiency of indium is improved. At the same time, the stirring system is always changing in speed, and the average speed is smaller than that of the uniform stirring system, so the energy consumption is reduced. The inclined-blade stirring system is a composite of axial flow and radial paddle, which can enhance the axial mixing capacity of the stirring system in the leaching experiment. It can improve the phenomenon that the powder material easily sinks to the bottom, and at the same time, it can reduce the resistance of the fluid to the paddle surface and reduce the energy consumption. The stirring system with baffles can also increase the axial mixing capacity of the solid-liquid two-phase system. In the leaching experiment process, the powder material particles move upward after hitting the baffle. The mixing effect of the powder material particles and the hydrochloric acid system is improved, and the leaching efficiency is improved. The addition of bottom blowing can effectively improve the problem of particle aggregation at the center position of the bottom of the chemical reactor, increase the contact area of the powder material particles and the hydrochloric acid, and improve the leaching efficiency.

[0036] The reaction of high-indium-content waste material and hydrochloric acid is as follows:

[0037] In2O3+6HCl=2InCl3+3H2O

[0038] SnO2+6HCl=SnCl4+3H2O

[0039] Example 1

[0040] 1.1 Experimental raw materials

[0041] The high-indium-content powder material used in the test is ITO waste target material and ITO peeled from waste LCD after pre-enrichment, crushing and ball milling; and industrial hydrochloric acid.

[0042] 1.2 Experimental procedure

[0043] Firstly, the two high-indium-containing materials were crushed and ground into powders with a particle diameter of 200-400 mesh, and a hydrochloric acid solution with a concentration of 4 mol / L was prepared. 50 g of high-indium-containing material powder was put into a linear stirring and nonlinear stirring system, and hydrochloric acid solution was added at a liquid-solid ratio of 10:1, with a concentration of 4 mol / L. The reaction temperature was controlled, and a uniform speed, half-wave frequency function, and H frequency function were output by a function generator to control the rotation of the stirring paddle (45°). After the reaction started, the bottom blowing valve was opened to assist the leaching of indium in the two high-indium-containing materials. The reaction leaching time was 150 min.

[0044] 1.3 Experimental results

[0045] Table 1. Statistical table of intensified leaching test results of waste ITO target material with high indium content

[0046]

[0047] Table 2. Statistical table of intensified leaching test results of high-indium-containing waste material obtained by pre-enrichment of waste liquid crystal display

[0048]

[0049] Example 2

[0050] 2.1 Effect of temperature on leaching rate

[0051] As can be seen from Table 1, among the four stirring modes, as the reaction temperature increases, the molecular thermal motion intensifies, the diffusion rate of the solute increases, and the leaching rate of indium in the high-indium-containing powder material also increases. In the uniform speed stirring system, when the reaction temperature is 80°C and the paddle speed is 60 rpm, the leaching rate of indium reaches 75.12%, which is 26.02% higher than that at 60°C. In the H variable speed system, the leaching rate of indium at 80°C is 26.16% higher than that at 60°C. In the H variable speed plus bottom blowing stirring system, the leaching rate of indium at 80°C is 24.79% higher than that at 60°C. It can be seen that the reaction temperature has a great effect on the leaching experiment of indium, and since the hydrochloric acid system is volatile, the reaction temperature is controlled at 80°C.

[0052] As can be seen from Table 2, in the uniform speed stirring system, when the temperature is 80°C, the leaching rate of indium in the waste liquid crystal display high-indium-containing material is 70.31%, which is 25.08% higher than that at 60°C. In the H variable speed system, the leaching rate of indium at 80°C is 24.92% higher than that at 60°C. In the H variable speed plus bottom blowing stirring system, the leaching rate of indium at 80°C is 28.22% higher than that at 60°C. It can be seen that the present application has an advantage in high-indium-containing materials.

[0053] 2.2 Effect of paddle speed on leaching rate

[0054] As can be seen from Table 1, the increase of stirring speed increases the mass transfer rate between solute and solvent, thereby increasing the leaching rate. In the three stirring modes, the leaching rate of indium increases with the increase of the maximum stirring speed. In the H variable speed and bottom blowing stirring system, when the variable speed range is 0-150 rpm, the leaching rate of indium reaches 97.21%, which is increased by 11.08% compared with the variable speed range of 0-60 rpm. As can be obviously seen from Table 2, in the H variable speed and bottom blowing stirring system, when the variable speed range is 0-150 rpm, the leaching rate of indium reaches 96.35%, which is increased by 8.72% compared with the variable speed range of 0-60 rpm.

[0055] 2.3 Influence of different stirring modes on leaching rate

[0056] In view of the problem of mixing isolation zone in the traditional uniform speed stirring system, three stirring leaching systems, i.e., a half-wave variable speed stirring leaching system, an H variable speed stirring leaching system and an H variable speed stirring system with bottom blowing, are provided. As can be seen from Table 1, in the intensified leaching experiment of waste ITO target material, under the condition of a temperature of 80°C and a maximum speed of 150 rpm, the leaching rate of the H variable speed stirring leaching system reaches 95.96%, which is increased by 4.09% compared with the uniform speed stirring system and is increased by 3.61% compared with the half-wave variable speed stirring system. In the H variable speed stirring system with bottom blowing, the leaching rate of indium reaches 97.21%, which is increased by 7.08% compared with the uniform speed stirring system and is increased by 1.25% compared with the H variable speed stirring system.

[0057] As can be seen from Table 2, in the intensified leaching experiment of high-indium-containing material of waste liquid crystal display, under the condition of a temperature of 80°C and a speed range of 0-150 rpm, the leaching rate of the H variable speed stirring leaching system reaches 93.73%, which is increased by 5.04% compared with the uniform speed stirring system and is increased by 4.12% compared with the half-wave variable speed stirring system. In the H variable speed stirring system with bottom blowing, the leaching rate of indium reaches 96.35%, which is increased by 7.66% compared with the uniform speed stirring system and is increased by 2.62% compared with the H variable speed stirring system.

[0058] As can be seen from Table 1 and Table 2, when the variable speed range is 0-150 rpm, the average speed of the H variable speed function is 86.56 rpm and the power is greater than 0.0012 w, the average speed of the half-wave variable speed function is 94.75 rpm and the power is greater than 0.0014 w. When the speed is 120 rpm, the average speed of the uniform speed stirring system is 120 rpm and the power is greater than 0.0042 w. It can be obviously seen that the power consumption of the H variable speed system is reduced by 60%-63% compared with the uniform speed stirring system, and is reduced by 21%-24.28% compared with the half-wave variable speed. It can be seen that the method for intensifying leaching of indium from high-indium-containing material can not only increase the leaching rate of indium, but also achieve the effect of energy saving and emission reduction.

[0059] In summary, the leaching rate of high indium-containing waste in half-wave speed stirring system, H speed stirring system, H speed stirring system with bottom blowing stirring system can be significantly improved, and the leaching rate can reach more than 92% at 80℃, and the leaching rate in H speed stirring system with bottom blowing stirring system is as high as more than 96%. At the same time, the stirring power is also significantly reduced, and the stirring power in the variable speed stirring system is reduced by 50%-63% compared with the uniform speed stirring system.

[0060] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0061] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of enhancing leaching of high indium-bearing scrap material, characterized by, The method comprises the following steps: I. feeding high-indium-containing waste to a chemical reactor, and adding hydrochloric acid according to a liquid-solid ratio; II. heating the chemical reactor by using a water bath system, starting a nonlinear stirring system, and outputting a function to a frequency converter by using a function generator to realize control of the nonlinear stirring system, and simultaneously starting a jetting system; The function output by the function generator in step II is a trapezoidal function, a half-wave sine function or an H variable speed function; III. after leaching is completed, the water bath system, the nonlinear stirring system and the jetting system are turned off, and the leaching liquid is separated from the leaching residue.

2. The method of leaching high indium containing scrap material according to claim 1, wherein The high-indium-containing waste in step I is fed to the chemical reactor after being crushed and ball milled; The particle size of the ball milled material is 200-400 mesh.

3. The method of leaching high indium containing scrap material according to claim 1, wherein The liquid-solid ratio in step I is 10:1-30:1, and the concentration of the hydrochloric acid is 3-6 mol / L.

4. The method of leaching high indium containing scrap material according to claim 1, wherein The heating temperature of the water bath system in step II is 50-85℃.

5. The method of leaching high indium containing scrap material according to claim 1, wherein The rotating speed of the nonlinear stirring system in step II is 0-150 rpm, and the variable speed period is 0-20 s.

6. The method of leaching high indium containing scrap material according to claim 1, wherein The speed of the jetting system in step II is 0.01-0.05 m / s.

7. The method of leaching high indium containing scrap material according to claim 1, wherein The leaching time in step III is 120-150 min.

8. An apparatus for the leaching of high-indium-containing waste material according to the method of any one of claims 1 to 7, characterized in that The device comprises a support, a nonlinear stirring system, a water bath system, a chemical reactor and a jetting system; The stirring part of the nonlinear stirring system extends into the chemical reactor from the center of the chemical reactor, and the nonlinear stirring system is fixed on the support; The heating part of the water bath system submerges the middle and lower parts of the chemical reactor; The jetting system is connected to the bottom of the chemical reactor; The paddle of the stirring part is an inclined paddle with an inclination of 45°; The top of the chemical reactor is provided with a baffle, the bottom is a round bottom, and an interface connected to the jetting system is arranged on the bottom; The nonlinear stirring system comprises a frequency converter, a function generator, a three-phase asynchronous motor and a condensation reflux device; The frequency converter is fixed on the support, and one end of the frequency converter is connected to the function generator, and the other end is connected to the three-phase asynchronous motor; The three-phase asynchronous motor is located directly above the chemical reactor; The condensation reflux device is used for condensation of the chemical reactor; The three-phase asynchronous motor controls the stirring part.

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