Continuous powder rinsing process and system for electrolytic manganese dioxide

Abstract

The continuous powder rinsing process comprises the following steps: S1, grinding the electrolytic manganese dioxide into powder, and carrying out primary magnetic separation on the ground powder to remove iron; s2, hot water is added into the powder obtained after primary magnetic separation and iron removal in the S1, and primary rinsing is carried out; s3, performing secondary pipeline iron removal on the electrolytic manganese dioxide rinsing slurry obtained after primary rinsing in S2; s4, the manganese dioxide rinsing slurry obtained after secondary pipeline iron removal in the S3 is subjected to primary deep-cone thickening, obtained primary deep-cone thickening supernate is returned to the leaching process, and a rinsing agent and water are added into obtained primary deep-cone thickening underflow for secondary rinsing; s5, filtering the electrolytic manganese dioxide rinsing slurry obtained after secondary rinsing in S4 to obtain a filter cake product, and carrying out secondary deep cone thickening process on the filtered washing water; and S6, secondary deep cone dense underflow obtained in the step S5 is filtered again. On the basis of ensuring the impurity removal efficiency and the quality of the electrolytic manganese dioxide finished product, the process flow is simplified, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of electrolytic manganese dioxide, in particular to a continuous powder rinsing process and system for electrolytic manganese dioxide. Background Art

[0002] During the electrolysis of manganese dioxide, impurity metal ions such as Ca, Mg, and Cu will be precipitated at the anode together with Mn ions. At the same time, during the process of electrolytic manganese dioxide leaving the tank, due to the effect of electrolyte evaporation inhibitor, electrolyte with MnSO4 and H2SO4 as the main components will also be entrained. The attached electrolyte and impurity metal ions need to be removed through the rinsing process. The operation of this process is directly related to the pH value, fineness, particle size distribution, impurity content and other important parameters of the electrolytic manganese dioxide product, so the requirements for the process of this process are very strict.

[0003] At present, the post-processing process of electrolytic manganese dioxide semi-finished products adopted by most electrolytic manganese dioxide manufacturers at home and abroad is mainly based on particle rinsing. The process includes "semi-finished product crushing-rinsing-grinding-drying-blending-iron removal-packaging" and other processes. However, this process has the following disadvantages: 1. The solid-liquid contact area in the rinsing process is small, resulting in large water consumption and rinsing agent consumption; 2. The crushed materials are uneven, affecting the rinsing effect; 3. The removal effect of magnetic impurities is poor: during the rinsing process, the rinsing agent will react with Fe 3+ The reaction generates Fe(OH)3 precipitate which is mixed into the electrolytic manganese dioxide powder after rinsing, affecting the product quality; 4. The operation process is intermittent and the operation cycle is long.

[0004] The utility model patent with publication number CN213349964U discloses an electrolytic manganese dioxide rinsing device, including a rinsing chamber and a sedimentation chamber, wherein the rinsing chamber is arranged above the sedimentation chamber, a feed pipe is arranged on one side of the lower end of the rinsing chamber, a valve is arranged on the feed pipe, and the rinsing chamber is connected with the sedimentation chamber through the feed pipe; a discharge port is arranged at the lower part of the sedimentation chamber, an overflow port is arranged at the upper part of the sedimentation chamber, the overflow port is arranged on the other side of the feed pipe, a baffle is arranged vertically between the feed pipe and the overflow port in the sedimentation chamber, and there is a distance between the baffle and the bottom plate of the sedimentation chamber; the stirring device includes a motor, a stirring shaft and a stirring assembly, the motor is fixed at the upper end of the rinsing chamber, one end of the stirring shaft is connected to the motor output shaft, and the other end extends into the rinsing chamber, the stirring assembly is symmetrically connected to both sides of the stirring shaft, and the device is provided with a rinsing chamber and a sedimentation chamber to rinse manganese dioxide. However, the above scheme has the following disadvantages and shortcomings in actual application: 1. The method of removing magnetic impurities (Fe) in the electrolytic manganese dioxide semi-finished product is not considered during the rinsing process, resulting in reduced product performance; 2. The rinsing wastewater after rinsing is not involved in the subsequent treatment process and cannot be recycled, resulting in increased water consumption.

[0005] The invention patent with publication number CN116177631A discloses a recycling device for rinsing wastewater of electrolytic manganese dioxide, including a rinsing box, a top wall of the rinsing box is provided with a feed port, and a side wall of the rinsing box is provided with a water inlet; a second screen is provided in the rinsing box, and a filtering device is provided on the top of the second screen; the side wall of the rinsing box is also connected to a second pipe, the second pipe is located below the second screen, a second valve is provided in the second pipe, and an end of the second pipe away from the rinsing box is connected to a preliminary treatment device; a first pipe is connected to the side wall of the rinsing box away from the second pipe, the first pipe is located below the second screen, a first valve is provided in the first pipe, and an end of the first pipe away from the rinsing box is connected to a third water pump, the input end of the third water pump is connected to the first pipe, the output end of the third water pump is connected to the third pipe, and an end of the third pipe away from the third water pump is connected to the rinsing box. The utility model patent with publication number CN213357768U discloses a recycling device for rinsing wastewater of electrolytic manganese dioxide, comprising a rinsing tank, a wastewater collecting tank, a leaching residue washing tank, a leaching tank, a first filter press, a purification and impurity removal tank, a second filter press and an electrolytic tank, wherein the rinsing tank, the wastewater collecting tank and the leaching residue washing tank are connected in sequence through a wastewater pipe, and the rinsing tank is provided with a hot water inlet pipe; the leaching residue washing tank is connected to the leaching tank through a leaching residue pipe and a washing water pipe respectively, and is connected to the first filter press through a washing residue pipe, and the first filter press is connected to the leaching tank through a filtrate pipe; the leaching tank is connected to the purification and impurity removal tank through a leaching liquid pipe, and the purification and impurity removal tank is connected to the second filter press through a conveying pipe, the second filter press is connected to the electrolytic tank through a filtrate pipe, and is connected to the leaching residue washing tank through a filter residue pipe. However, the above scheme has the following disadvantages and shortcomings in actual application: 1. There are many auxiliary equipments, which occupy a large amount of working space; 2. There are too many purification sections for electrolytic manganese dioxide rinsing wastewater, which will indirectly increase the total water consumption during the electrolytic manganese dioxide rinsing operation and prolong the operation time.

[0006] The Chinese patent with publication number CN103572317A discloses a refining method for an electrolytic manganese dioxide product, which includes six-stage rinsing process, grinding, magnetic separation, screening, blending and other steps, hot water acid washing, weak alkali rinsing, strong alkali rinsing, hot water alkali washing, dilute acid backwashing, and hot water rinsing under high temperature conditions to remove sulfuric acid and low-valent manganese remaining in the electrolytic manganese dioxide, and after grinding, powder magnetic separation is performed to remove impurities from the residual Fe in the finished product, and then the oscillating screen technology is used to control the particle size distribution of the finished product to reduce the mixing of coarse particles and other non-metallic impurities in the powder, and the electrolytic manganese dioxide product is obtained after blending. However, the patent has the following shortcomings and deficiencies in the actual application process: 1. The rinsing process is complicated, and each rinsing process requires more time, so the impurity removal rate is slow, the rinsing cycle is long, and it is difficult to realize the automation process; 2. The amount of rinsing liquid is too large, and a large amount of resources need to be consumed to recycle it, causing greater environmental pressure. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a continuous powder rinsing process and system for electrolytic manganese dioxide in view of the shortcomings of the existing technology, which simplifies the process flow, reduces costs and is environmentally friendly while ensuring the impurity removal efficiency and the quality of the electrolytic manganese dioxide product.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A continuous powder rinsing process for electrolytic manganese dioxide comprises the following steps:

[0010] S1, grinding the electrolytic manganese dioxide into powder, and subjecting the ground electrolytic manganese dioxide powder to magnetic separation for iron removal;

[0011] S2, adding hot water to the electrolytic manganese dioxide powder after the iron is removed by magnetic separation in S1, and performing a rinsing step;

[0012] S3, performing secondary pipeline iron removal on the electrolytic manganese dioxide rinsing slurry obtained after the primary rinsing in S2;

[0013] The manganese dioxide rinsing slurry after secondary iron removal in S4 and S3 is subjected to a deep cone thickening, and a rinsing agent and water are added to the obtained primary deep cone thickening underflow for secondary rinsing;

[0014] The electrolytic manganese dioxide rinse slurry obtained after the secondary rinsing in S5 and S4 is filtered to obtain a filter cake product, and the washing water is filtered for secondary deep cone thickening;

[0015] The secondary deep cone dense underflow obtained in S6 and S5 is filtered again.

[0016] The present invention solves the following technical problems: 1. The grinding section is adjusted to the front end of the rinsing section, and the improved process and section can ensure the powder quality and accelerate the rinsing efficiency; 2. The primary magnetic separation iron removal is placed before the rinsing section, which greatly reduces the content of impure iron in the finished product, and solves the problem that the impurity iron removal efficiency is low and multiple rinsing processes are required in the electrolytic manganese dioxide rinsing process; 3. A pipeline iron remover is added, which can remove the impurity iron while transporting the electrolytic manganese dioxide slurry, and realize the continuous automation of the iron removal and rinsing process; 4. A deep cone thickening device is added to accelerate the solid-liquid separation effect and realize the integration of the solid-liquid separation process and the supernatant purification process; 5. Based on the pipeline iron remover and the deep cone thickening device, a new continuous automated rinsing process of "hot water rinsing-normal temperature alkaline rinsing" is formed, which solves the problem that the electrolytic manganese dioxide rinsing process is complicated and the rinsing reagent consumption is large.

[0017] In a preferred embodiment of the present invention, in S1, the mesh size of the electrolytic manganese dioxide after grinding is 100-450 meshes, preferably 100-350 meshes.

[0018] The grinding section is adjusted to the front end of the rinsing section, and the size of the solid particles is controlled in the grinding section. The improved process and section can ensure the powder quality and accelerate the rinsing efficiency.

[0019] In a preferred embodiment of the present invention, in S1, the magnetic field strength of the primary magnetic separation and iron removal is set in the range of 5000 to 8000 Gs, preferably 7000 to 8000 Gs.

[0020] The electrolytic manganese dioxide powder after the primary magnetic separation and iron removal has an impurity iron content in the range of 30 to 40 ug / g. The magnetic field strength of the primary magnetic separation and iron removal can ensure a high recovery rate of the electrolytic manganese dioxide.

[0021] In a preferred embodiment of the present invention, the temperature range of the hot water in S2 is 70-80°C, preferably 75-80°C.

[0022] The main purpose of the hot water rinse is to remove soluble impurities (Mg, Cu, SO4 2- The main purpose is to ensure that the soluble impurities are removed quickly without destroying the crystal structure. If the rinsing temperature is too high, the crystal structure of the electrolytic manganese dioxide will change, affecting its electrochemical properties. If the rinsing temperature is too low, the soluble impurities cannot be removed quickly and effectively, affecting the purity of manganese dioxide.

[0023] In a preferred embodiment of the present invention, in S3, the magnetic field setting range for secondary pipeline iron removal is 8000-12000 Gs, preferably 10000-12000 Gs.

[0024] The impurity iron content of the slurry after secondary iron removal is in the range of 25 to 30ug / g. After the secondary iron removal process, the iron content in the product is reduced by about 60% compared with the existing electrolytic manganese dioxide particle rinsing process, which can greatly improve the conductivity, battery capacity and cycle stability of electrolytic manganese dioxide.

[0025] In a preferred embodiment of the present invention, in S4, rinse agent and water are added to the primary deep cone concentrated underflow to adjust the pH value to 4.0-4.5.

[0026] Compared with the existing electrolytic manganese dioxide particle rinsing process, the pH adjustment range is acidic, which can avoid the formation of Fe(OH)3 and reduce the consumption of alkaline rinsing agents. If the pH value is adjusted too low, the solubility of manganese dioxide will increase, resulting in product loss and affecting the final yield.

[0027] In a preferred embodiment of the present invention, in S4, the rinsing agent is one or more of NaOH, NaHCO3, and NH4HCO3; preferably NaHCO3.

[0028] The main advantages of NaHCO3 rinse agent: 1. NaHCO3 has good buffering capacity and can maintain a stable pH value during the rinsing process, avoiding changes in manganese dioxide performance caused by pH fluctuations; 2. NaHCO3 has low toxicity and use costs; 3. NaHCO3 has higher solubility.

[0029] In a preferred embodiment of the present invention, in S4, the liquid-to-solid ratio of the manganese dioxide rinsing slurry after the secondary pipeline iron removal is 3-3.5:1, the sedimentation rate of the manganese dioxide particles is in the range of 0.01-0.03 m / s, and the solid mass fraction of the primary deep cone dense underflow is in the range of 70-80wt%.

[0030] The deep cone thickening process can achieve the best settling rate matching the deep cone thickening equipment by controlling parameters such as the liquid-solid ratio and the diameter of the solid particles, thereby achieving rapid separation of the solid and liquid phases in the manganese dioxide slurry. The purpose of setting the solid mass fraction range of the underflow is to ensure the liquid-solid separation effect while improving the fluidity of the underflow as much as possible. If the underflow solid mass fraction is too low, the solid-liquid separation effect is poor. If the underflow solid mass fraction is too high, there is a lack of fluidity and it may cause the underflow delivery pump to be blocked.

[0031] In a preferred embodiment of the present invention, the secondary deep cone concentrated supernatant obtained in S5 can be sent to a sewage treatment plant for treatment or returned to a primary rinsing process according to its impurity content.

[0032] The electrolytic manganese dioxide in S1 is derived from being stripped from the anode plate.

[0033] In S1, the size of the electrolytic manganese dioxide fragments is 20 to 50 mm.

[0034] S1 medium grinding adopts Raymond mill.

[0035] The grading and screening device equipped with the Raymond mill can sort out powdered materials with a mesh size of 100 to 450, and at the same time regrind unqualified materials, thereby improving the particle quality of the electrolytic manganese dioxide powder raw material and improving the rinsing efficiency.

[0036] After the iron is removed by magnetic separation in S1, the powder is sent to a collector for collection; in S2, the electrolytic manganese dioxide powder in the collector is sent to a primary rinsing tank through a screw metering conveyor.

[0037] The temperature of the rinse agent and water in S4 is normal temperature.

[0038] In S5, a belt filter is used for filtration.

[0039] In S5, the water content of the filter cake is in the range of 15-20 wt%.

[0040] In S6, the solid mass fraction of the secondary deep cone dense underflow is in the range of 70 to 80 wt%.

[0041] The present invention also discloses an electrolytic manganese dioxide continuous powder rinsing system, comprising a powder material magnetic separator, a primary rinsing tank and a secondary rinsing tank, and also comprising an electrolytic manganese dioxide grinding unit, the discharge port of the electrolytic manganese dioxide grinding unit is connected with the feed port of the powder material magnetic separator, the discharge port of the powder material magnetic separator is connected with the feed port of the primary rinsing tank, the bottom liquid outlet of the primary rinsing tank is connected with the feed port of a pipeline iron remover, the discharge port of the pipeline iron remover is connected with the feed port of a primary deep cone thickener, the bottom flow discharge port of the primary deep cone thickener is connected with the feed port of the secondary rinsing tank, the bottom liquid outlet of the secondary rinsing tank is connected with the feed port of a belt filter, the wash water liquid outlet of the belt filter is connected with the feed port of a secondary deep cone thickener, and the bottom flow discharge port of the secondary deep cone thickener is connected with the belt filter.

[0042] The electrolytic manganese dioxide grinding unit comprises a Raymond mill, the Raymond mill is equipped with a grading and screening device, and the discharge port of the Raymond mill is connected to the feed port of the powdered material magnetic separator.

[0043] The discharge port of the powder material magnetic separator is communicated with the feed port of the collector, the discharge port of the collector is communicated with the feed port of the spiral metering conveyor, and the discharge port of the spiral metering conveyor is communicated with the feed port of the primary rinsing tank.

[0044] In view of the problems existing in the existing process and the above-mentioned patents in the electrolytic manganese dioxide rinsing section, the present invention proposes a new continuous powder rinsing process and system for electrolytic manganese dioxide, which are as follows: 1. The grinding section is adjusted to the front end of the rinsing section, and the size of the solid particles is controlled in the grinding section. The improved process and section can ensure the powder quality and accelerate the rinsing efficiency; 2. The rinsing section is changed to two-stage rinsing, one stage uses hot water rinsing, and the second stage uses normal temperature alkaline rinsing. The new rinsing process can shorten the rinsing time, simplify the rinsing process, and reduce the consumption of rinsing agents; 3. Permanent magnetic iron removal and pipeline iron removal processes are added at the front end of a hot water rinsing section and an alkaline rinsing section respectively. The two newly added iron removal processes can effectively prevent impurity iron from being mixed into the finished electrolytic manganese dioxide product in the form of Fe(OH)3 precipitation during the alkaline rinsing process, greatly reducing the harm of impurity iron to the quality of electrolytic manganese dioxide products, thereby ensuring the rinsing effect, simplifying the rinsing process, and ensuring the continuity and automatic operation of the "permanent magnetic iron removal-hot water rinsing-pipeline iron removal-alkaline rinsing" process; 4. A new deep cone thickening device is added to accelerate the solid-liquid separation process of the slurry after rinsing. At the same time, a filter plate is provided on the upper part of the thickener, which can perform multi-level filtration on the supernatant after deep cone thickening, realizing the integration of the solid-liquid separation process and the supernatant purification process, reducing the number of post-rinsing liquid purification equipment, and saving working space.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The present invention first grinds the electrolytic manganese dioxide into powder, and controls the mesh size to improve the particle quality of the electrolytic manganese dioxide powder raw material and improve the rinsing efficiency; 2. A magnetic separation iron removal is provided before the first rinsing and a secondary pipeline iron removal is provided after the rinsing, which can effectively reduce the formation of Fe(OH)3 precipitation during the rinsing process, reduce the content of magnetic impurities (Fe) in the rinsing slurry, ensure the rinsing effect, and simplify the rinsing process; 3. The deep cone thickening device can accelerate the solid-liquid separation process, and the filtering device provided inside it can realize multiple purifications of the supernatant, reducing the electrolytic manganese dioxide The loss of manganese oxide can be reduced, shortening the rinsing operation time; 4. The supernatant after deep cone thickening can be returned to the rinsing process once, reducing water consumption; 5. The application of deep cone thickening device and pipeline iron remover can ensure the continuous automated production of the new rinsing process, while reducing the number and types of rinsing liquid recovery equipment and improving the space utilization of powder rinsing equipment; 6. The "hot water rinsing-normal temperature alkaline rinsing" process improved on the basis of deep cone thickening device and pipeline iron remover can shorten the rinsing time, simplify the rinsing process and reduce the consumption of rinsing agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a process flow chart of continuous powder rinsing of electrolytic manganese dioxide according to an embodiment of the present invention.

[0048] Figure 2This is a schematic structural diagram of a novel continuous powder rinsing system for electrolytic manganese dioxide according to an embodiment of the present invention.

[0049] Among them: 1-Raymond mill, 2-powdered material magnetic separator, 3-collector, 4-screw metering conveyor, 5-primary rinsing tank, 6-pipeline iron remover, 7-primary deep cone thickener, 8-secondary rinsing tank, 9-belt filter, 10-secondary deep cone thickener. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0051] Example 1

[0052] like Figure 1-Figure 2 As shown, the present invention comprises the following steps:

[0053] S1. The electrolytic manganese dioxide fragments (size of 20-30 mm) peeled off from the anode plate are sent to a Raymond mill for grinding. The ground powder (mesh size of 350-450 mesh) is subjected to a magnetic separator for iron removal (magnetic field strength of 5000 Gs) and then sent to a collector for collection;

[0054] S2. The electrolytic manganese dioxide powder (impurity iron content 38-40ug / g) after primary iron removal is sent into a primary rinsing tank through a screw metering conveyor, and hot water (temperature 70°C) is added to perform a rinsing process;

[0055] S3, the electrolytic manganese dioxide rinsing slurry obtained after the first rinsing is pumped into the pipeline iron remover for secondary iron removal process (magnetic field strength 8000Gs);

[0056] S4, the manganese dioxide rinsing slurry after secondary iron removal is subjected to a deep cone thickening process (solid-liquid ratio 3.5:1, sedimentation rate 0.01m / s), the obtained deep cone thickening supernatant is returned to the leaching process, and the obtained deep cone thickening underflow (solid mass fraction 70-73wt%) is pumped into the secondary rinsing tank, and after adding rinsing agent (NaHCO3) and water (normal temperature) to adjust to a suitable PH value (4.5), a secondary rinsing process is carried out;

[0057] S5. The electrolytic manganese dioxide rinsing slurry obtained after the secondary rinsing is pumped into a belt filter for filtration to obtain a filter cake product (the filter cake contains 18-20wt% water and the impurity iron content after drying is 28-30ug / g). The filtered washing water is subjected to a secondary deep cone thickening process (solid-liquid ratio 3.5:1, sedimentation rate 0.01m / s);

[0058] S6. After the secondary deep cone thickening process is completed, the obtained secondary deep cone thickening supernatant can be flexibly sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content. The obtained secondary deep cone thickening underflow (solid mass fraction 70-73wt%) is returned to the belt filter for another filtration process.

[0059] Testing methods and testing standards

[0060] Detection methods: ion selective electrode (ISE), atomic absorption spectrometry (AAS);

[0061] Testing specification: "QB / T2106-2022 General Technical Specifications for Electrolytic Manganese Dioxide for Batteries".

[0062] Other technical indicators are shown in Table 1:

[0063] Table 1 Technical indicators in Example 1

[0064]

[0065] Example 2

[0066] S1. The electrolytic manganese dioxide fragments (size of 30-40 mm) peeled off from the anode plate are sent to a Raymond mill for grinding. The ground powder (mesh size of 250-350 mesh) is subjected to a magnetic separator for iron removal (magnetic field strength of 7000 Gs) and then sent to a collector for collection;

[0067] S2. The electrolytic manganese dioxide powder (impurity iron content 35-38ug / g) after primary iron removal is sent into a primary rinsing tank through a screw metering conveyor, and hot water (temperature 75°C) is added to perform a rinsing process;

[0068] S3, the electrolytic manganese dioxide rinsing slurry obtained after the first rinsing is pumped into the pipeline iron remover for secondary iron removal process (magnetic field strength 10000Gs);

[0069] S4. The manganese dioxide rinsing slurry after secondary iron removal undergoes a deep cone thickening process (solid-liquid ratio 3.2:1, sedimentation rate 0.02m / s), and the obtained deep cone thickening supernatant is returned to the leaching process, and the obtained deep cone thickening underflow (solid mass fraction 73-77wt%) is pumped into the secondary rinsing tank, and after adding rinsing agent (NaHCO3) and water (normal temperature) to adjust to a suitable pH value (4.2), a secondary rinsing process is performed;

[0070] S5. The electrolytic manganese dioxide rinsing slurry obtained after the secondary rinsing is pumped into a belt filter for filtration to obtain a filter cake product (the filter cake contains 16-18wt% water and the impurity iron content after drying is 26-28ug / g). The filtrated washing water is subjected to a secondary deep cone thickening process (solid-liquid ratio 3.2:1, sedimentation rate 0.02m / s);

[0071] S6. After the secondary deep cone thickening process is completed, the obtained secondary deep cone thickening supernatant can be flexibly sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content. The obtained secondary deep cone thickening underflow (solid mass fraction 73-77wt%) is returned to the belt filter for another filtration process.

[0072] Other technical indicators are shown in Table 2:

[0073] Table 2 Technical indicators in Example 2

[0074]

[0075] Example 3

[0076] S1. The electrolytic manganese dioxide fragments (size of 40-50 mm) peeled off from the anode plate are sent to a Raymond mill for grinding. The ground powder (mesh size of 100-250 mesh) is subjected to a magnetic separator for iron removal (magnetic field strength of 8000 Gs) and then sent to a collector for collection;

[0077] S2. The electrolytic manganese dioxide powder (impurity iron content 30-35ug / g) after primary iron removal is sent into a primary rinsing tank through a screw metering conveyor, and hot water (temperature 80°C) is added to perform a rinsing process;

[0078] S3, the electrolytic manganese dioxide rinsing slurry obtained after the first rinsing is pumped into the pipeline iron remover for secondary iron removal process (magnetic field strength 12000Gs);

[0079] S4. The manganese dioxide rinsing slurry after secondary iron removal undergoes a deep cone thickening process (solid-liquid ratio 3:1, sedimentation rate 0.03m / s), the obtained deep cone thickening supernatant is returned to the leaching process, and the obtained deep cone thickening underflow (solid mass fraction 78-80wt%) is pumped into the secondary rinsing tank, and after adding rinsing agent (NaHCO3) and water (normal temperature) to adjust to a suitable PH value (4.0), a secondary rinsing process is carried out;

[0080] S5. The electrolytic manganese dioxide rinsing slurry obtained after the secondary rinsing is pumped into a belt filter for filtration to obtain a filter cake product (the filter cake contains 15-16wt% water and the impurity iron content after drying is 25-26ug / g). The filtered washing water is subjected to a secondary deep cone thickening process (solid-liquid ratio 3:1, sedimentation rate 0.03m / s);

[0081] S6. After the secondary deep cone thickening process is completed, the secondary deep cone thickening supernatant can be flexibly sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content. The secondary deep cone thickening underflow (solid mass fraction 78-80wt%) is returned to the belt filter for another filtration process.

[0082] Other technical indicators are shown in Table 3:

[0083] Table 3 Technical indicators in Example 3

[0084]

[0085] Comparative Example 1

[0086] The difference between this comparative example and the embodiment is that only permanent magnet iron removal is used, and there is no pipeline iron removal process. At the same time, the process flow is "semi-finished product crushing - rinsing - grinding - drying - permanent magnet iron removal".

[0087] S1. The electrolytic manganese dioxide fragments (size of 40-50 mm) peeled off from the anode plate are sent into a primary rinsing tank, and hot water (temperature 80° C.) and a rinsing agent (NaHCO3) are added to perform a rinsing process;

[0088] S2, the rinsed electrolytic manganese dioxide fragments are sent to a Raymond mill for grinding, and the ground powder (mesh size is 100-250 mesh) is dried and sent to a collector for collection;

[0089] S3. The dried electrolytic manganese dioxide powder is blended and then subjected to a permanent magnetic iron removal process (magnetic field strength 8000 Gs).

[0090] In this comparative example, the impurity iron content of the crude electrolytic manganese dioxide product obtained in each process section is as follows:

[0091] Table 4 Impurity iron content of the crude electrolytic manganese dioxide product obtained in Comparative Example 1

[0092]

[0093] In the present comparative example, since the impurity Fe in the rinsing process enters the manganese dioxide powder in the form of Fe(OH)3 precipitation, its magnetism is greatly weakened, so the impurity Fe cannot be effectively removed in the permanent magnetic iron removal process.

[0094] Comparative Example 2

[0095] The difference between this comparative example and the embodiment is that the magnetic field intensity during the iron removal process is changed.

[0096] S1. The electrolytic manganese dioxide fragments (size of 40-50 mm) peeled off from the anode plate are sent to a Raymond mill for grinding. The ground powder (mesh size of 100-250 mesh) is subjected to a magnetic separator for iron removal (magnetic field strength of 10000 Gs) and then sent to a collector for collection;

[0097] S2. The electrolytic manganese dioxide powder (impurity iron content 30-35ug / g) after primary iron removal is sent into a primary rinsing tank through a screw metering conveyor, and hot water (temperature 80°C) is added to perform a rinsing process;

[0098] S3, the electrolytic manganese dioxide rinsing slurry obtained after the first rinsing is pumped into the pipeline iron remover for secondary iron removal process (magnetic field strength 15000Gs);

[0099] S4. The manganese dioxide rinsing slurry after secondary iron removal undergoes a deep cone thickening process (solid-liquid ratio 3:1, sedimentation rate 0.03m / s), the obtained deep cone thickening supernatant is returned to the leaching process, and the obtained deep cone thickening underflow (solid mass fraction 78-80wt%) is pumped into the secondary rinsing tank, and after adding rinsing agent (NaHCO3) and water (normal temperature) to adjust to a suitable PH value (4.0), a secondary rinsing process is carried out;

[0100] S5. The electrolytic manganese dioxide rinsing slurry obtained after the secondary rinsing is pumped into a belt filter for filtration to obtain a filter cake product (the filter cake contains 15-16wt% water and the impurity iron content after drying is 25-26ug / g). The filtered washing water is subjected to a secondary deep cone thickening process (solid-liquid ratio 3:1, sedimentation rate 0.03m / s);

[0101] S6. After the secondary deep cone thickening process is completed, the secondary deep cone thickening supernatant can be flexibly sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content. The secondary deep cone thickening underflow (solid mass fraction 78-80wt%) is returned to the belt filter for another filtration process.

[0102] In the present comparative example, since the magnetic field strength applied in the two-stage iron removal process is too large, part of the electrolytic manganese dioxide is magnetized and removed together with the impurity iron, reducing the recovery rate of the electrolytic manganese dioxide (about 97%).

[0103] Comparative Example 3

[0104] The difference between this comparative example and the embodiment is that the process parameters of the deep cone thickening process are changed.

[0105] S1. The electrolytic manganese dioxide fragments (size of 10-20 mm) peeled off from the anode plate are sent to a Raymond mill for grinding. The ground powder (mesh size of 500-600 mesh) is subjected to a magnetic separator for iron removal (magnetic field strength of 8000 Gs) and then sent to a collector for collection;

[0106] S2. The electrolytic manganese dioxide powder (impurity iron content 30-35ug / g) after primary iron removal is sent into a primary rinsing tank through a screw metering conveyor, and hot water (temperature 80°C) is added to perform a rinsing process;

[0107] S3, the electrolytic manganese dioxide rinsing slurry obtained after the first rinsing is pumped into the pipeline iron remover for secondary iron removal process (magnetic field strength 12000Gs);

[0108] S4. The manganese dioxide rinsing slurry after secondary iron removal undergoes a deep cone thickening process (solid-liquid ratio 5:1, sedimentation rate 0.005m / s), the obtained deep cone thickening supernatant is returned to the leaching process, and the obtained deep cone thickening underflow (solid mass fraction 78-80wt%) is pumped into the secondary rinsing tank, and after adding rinsing agent (NaHCO3) and water (normal temperature) to adjust to a suitable PH value (4.0), a secondary rinsing process is carried out;

[0109] S5. The electrolytic manganese dioxide rinsing slurry obtained after the secondary rinsing is pumped into a belt filter for filtration to obtain a filter cake product (the filter cake contains 15-16wt% water and the impurity iron content after drying is 25-26ug / g). The filtered washing water is subjected to a secondary deep cone thickening process (solid-liquid ratio 5:1, sedimentation rate 0.005m / s);

[0110] S6. After the secondary deep cone thickening process is completed, the secondary deep cone thickening supernatant can be flexibly sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content. The secondary deep cone thickening underflow (solid mass fraction 78-80wt%) is returned to the belt filter for another filtration process.

[0111] Sedimentation rate calculation formula:

[0112]

[0113] Where, v is the sedimentation velocity (m / s); g is the acceleration due to gravity (about 9.81 m / s 2 );ρ s is the density of the particle (kg / m 3 );ρ f is the density of the fluid (kg / m 3 ), d is the diameter of the particle (m), and μ is the dynamic viscosity of the fluid (kg / (m·s))

[0114] Since the particle size is too large and the liquid-to-solid ratio is too high, the sedimentation rate is greatly reduced, and the rinsing cycle is extended (2 to 3 hours).

[0115] The technical indicators of the novel continuous powder rinsing process of the present invention are compared with the technical indicators of the particle rinsing process of the Chinese patent application with publication number CN103572317A as follows:

[0116] Table 5 Comparison of technical indicators of the present invention and the Chinese patent with publication number CN103572317A

[0117]

[0118]

[0119] Compared with the existing electrolytic manganese dioxide particle rinsing process, the electrolytic manganese dioxide powder rinsing process provided by this patent greatly reduces water consumption, steam consumption, rinsing cycle, rinsing agent types, and rinsing agent consumption while ensuring product quality, and can also achieve continuous automated production.

[0120] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A continuous powder rinsing process for electrolytic manganese dioxide, characterized in that: The steps include: S1, grinding the electrolytic manganese dioxide into powder, and subjecting the ground electrolytic manganese dioxide powder to magnetic separation for iron removal; S2, adding hot water to the electrolytic manganese dioxide powder after the iron is removed by magnetic separation in S1, and performing a rinsing step; S3, performing secondary pipeline iron removal on the electrolytic manganese dioxide rinsing slurry obtained after the primary rinsing in S2; The manganese dioxide rinsing slurry after secondary iron removal in S4 and S3 is subjected to a deep cone thickening, and a rinsing agent and water are added to the obtained primary deep cone thickening underflow for secondary rinsing; The electrolytic manganese dioxide rinse slurry obtained after the secondary rinsing in S5 and S4 is filtered to obtain a filter cake product, and the washing water is filtered for secondary deep cone thickening; The secondary deep cone dense underflow obtained in S6 and S5 is filtered again.

2. The electrolytic manganese dioxide continuous powder rinsing process according to claim 1, characterized in that: In S1, the mesh size of the electrolytic manganese dioxide powder is 100 to 450 meshes, preferably 100 to 350 meshes.

3. The continuous powder rinsing process of electrolytic manganese dioxide according to claim 1, characterized in that: In S1, the magnetic field strength of the primary magnetic separation and iron removal is set in the range of 5000 to 8000 Gs, preferably 7000 to 8000 Gs.

4. The continuous powder rinsing process of electrolytic manganese dioxide according to claim 1, characterized in that: The temperature of the hot water in S2 is in the range of 70 to 80°C, preferably 75 to 80°C.

5. The continuous powder rinsing process of electrolytic manganese dioxide according to claim 1, characterized in that: In S3, the magnetic field setting range for secondary pipeline iron removal is 8000-12000Gs, preferably 10000-12000Gs.

6. The continuous powder rinsing process of electrolytic manganese dioxide according to claim 1, characterized in that: In S4, a rinse agent and water are added to the primary deep cone concentrated underflow to adjust the pH value to 4.0-4.

5.

7. The continuous powder rinsing process of electrolytic manganese dioxide according to any one of claims 1 to 6, characterized in that: In S4, the rinsing agent is one or more of NaOH, NaHCO3, and NH4HCO3; preferably NaHCO3.

8. The continuous powder rinsing process of electrolytic manganese dioxide according to any one of claims 1 to 6, characterized in that: In S4, the liquid-to-solid ratio of the manganese dioxide rinsing slurry after the secondary pipeline iron removal is 3-3.5:1, the sedimentation rate of the manganese dioxide particles is in the range of 0.01-0.03 m / s, and the solid mass fraction of the primary deep cone dense underflow is in the range of 70-80wt%.

9. The continuous powder rinsing process of electrolytic manganese dioxide according to claim 1, characterized in that: The secondary deep cone concentrated supernatant obtained in S5 can be sent to a sewage treatment plant for treatment or returned to the primary rinsing process according to its impurity content.

10. A continuous powder rinsing system for electrolytic manganese dioxide, comprising a powder material magnetic separator (2), a primary rinsing tank (5) and a secondary rinsing tank (8), characterized in that: The invention also comprises an electrolytic manganese dioxide grinding unit, wherein the discharge port of the electrolytic manganese dioxide grinding unit is connected to the feed port of the powder material magnetic separator (2), the discharge port of the powder material magnetic separator (2) is connected to the feed port of the primary rinsing tank (5), the bottom liquid outlet of the primary rinsing tank (5) is connected to the feed port of the pipeline iron remover (6), the discharge port of the pipeline iron remover (6) is connected to the feed port of the primary deep cone thickener (7), the bottom flow discharge port of the primary deep cone thickener (7) is connected to the feed port of the secondary rinsing tank (8), the bottom liquid outlet of the secondary rinsing tank (8) is connected to the feed port of the belt filter (9), the wash water liquid outlet of the belt filter (9) is connected to the feed port of the secondary deep cone thickener (10), and the bottom flow discharge port of the secondary deep cone thickener (10) is connected to the belt filter (9).

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