A method for efficiently leaching manganese-containing oil sludge using oxalic acid and sulfuric acid

Abstract

The present invention belongs to the field of high-purity manganese sulfate smelting, and discloses a method for efficiently leaching manganese-containing oil sludge using oxalic acid and sulfuric acid, comprising the following steps: adding water to the manganese-containing oil sludge, stirring and beating, and then adding oxalic acid and sulfuric acid to leach, separate the solid and liquid, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product. The method can efficiently utilize the manganese resources in the manganese-containing oil sludge, and the manganese recovery rate is higher than 98%, which is conducive to the further preparation of industrial-grade manganese sulfate products; it can effectively process the manganese-containing oil sludge in the production line, reduce the amount of slag, and reduce the pressure of the slag warehouse; it can effectively recover a certain amount of fluorine in the slag, and subsequently recover the fluorine ions by extraction, turning waste into treasure, cleaning the environment, and reducing costs.

Description

Technical Field

[0001] The invention belongs to the field of high-purity manganese sulfate smelting, and specifically relates to a treatment method for efficiently leaching and utilizing manganese slag produced by manganese sulfate line extraction using oxalic acid and sulfuric acid. Background Art

[0002] In the process of extracting high-purity manganese sulfate, a certain amount of manganese-containing oil sludge is generated. The current treatment method is mostly landfilling in slag fields. Since the manganese-containing oil sludge generated in the process contains more than 35% manganese and has a high grade, direct landfilling causes waste of manganese resources and also pollutes the environment to a certain extent. It is necessary to treat it to recover the metallic manganese in the slag. The slag manganese contains not only some high-priced manganese, but also a large amount of fluorine and oil. The direct addition of sulfuric acid to leaching this part of the slag has a poor effect. A large amount of oil is wrapped on the surface of the slag, which hinders the acid leaching mechanism. Another part of the high-priced manganese cannot be directly leached by acid. After adding oxalic acid solution, the oil on the slag manganese can be hatched out and decomposed. In addition, oxalic acid will also reduce the high-priced manganese in the slag to divalent manganese, which is helpful for acid leaching of manganese in organic slag. At the same time, a large amount of fluorine in the slag can be recovered for subsequent extraction to remove calcium and magnesium, thereby achieving an important feasible solution for efficient utilization of manganese resources and secondary recovery of fluorine, and is also an effective means of treating solid waste to purify the environment. Summary of the invention The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology and provide a technical solution to solve the above technical problem. The technical solution proposed by the present invention is: A method for leaching and recovering manganese-containing oil sludge using oxalic acid and sulfuric acid comprises the following steps: adding water to the manganese-containing oil sludge, stirring and beating to mix well, adding oxalic acid and sulfuric acid to carry out leaching, solid-liquid separation, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product.

[0003] If sulfuric acid is used directly and manganese-containing sludge is directly in a high-temperature superacid environment, the manganese leaching rate in the organic slag is less than 70%, and the recovery rate of metallic manganese is less than 65%, which is a great loss for enterprises producing manganese-based products. In order to increase the leaching rate of manganese-containing sludge to more than 95% without affecting the performance of manganese sulfate products, it is an important technical issue in the high-purity manganese sulfate production line. In the extraction section of manganese sulfate products, manganese-containing sludge is produced, which has a high oil content and is attached to the manganese slag, hindering the direct acid leaching of sulfuric acid and manganese-containing sludge. The organic slag contains oxides higher than divalent manganese, which cannot be directly leached by concentrated sulfuric acid. A reducing agent needs to be added to dissolve and remove the oil in the slag without affecting the performance of the manganese sulfate product.

[0004] Therefore, the present invention also adds oxalic acid as a reducing agent. After the oxalic acid is added, the oil content of the manganese-containing sludge can be emulsified, and the high-valent manganese in the organic phase slag can be reduced to the maximum extent, which is helpful for sulfuric acid leaching of metallic manganese and fluorine in the slag and improving the manganese recovery rate in the organic slag. The specific reaction principle is as follows: 2MnO2+2H2C2O4+2H2SO4=2MnSO4+4CO2↑+4H2O; Mn+H2SO4=MnSO4+H2↑ ； The above reaction technology principle: using the characteristics of oxalic acid as an organic matter, in the process of reacting with manganese-containing sludge, it can simultaneously achieve the effect of dissolving organic components, promote the reaction of sulfuric acid, oxalic acid and manganese-containing sludge, and at the same time it has reducing properties, reducing manganese oxides higher than divalent manganese in manganese-containing sludge into divalent manganese ions. There are strict requirements for the amount of oxalic acid added. If the amount of oxalic acid added is too high, part of the manganese will be precipitated and wasted during the leaching process. If the amount of oxalic acid is too low, it is not enough to reduce the manganese in the organic slag into divalent manganese and decompose the oil on the organic slag. The effect of adding oxalic acid: it promotes the reaction of concentrated sulfuric acid and manganese-containing sludge, reduces the industrial production cost of manganese sulfate, and increases the production efficiency of manganese sulfate. After the introduction of oxalic acid, it has little effect on the performance of the subsequent impurity removal to make manganese sulfate products, which can meet customer needs. This process cannot use other reagents to replace oxalic acid. Other reducing organic matter other than oxalic acid is difficult to separate, and the separation cost is high. The related impurities are difficult to remove in the manganese sulfate product, affecting the performance of the manganese sulfate product.

[0005] In the above method, preferably, the manganese-containing sludge is the manganese-containing sludge produced in the manganese sulfate extraction section, which contains manganese oxide, metallic manganese, manganese fluoride and some organic components.

[0006] Preferably, the oxalic acid is industrial grade oxalic acid; and the sulfuric acid is industrial grade sulfuric acid. Preferably, the amount of oxalic acid added is 0.7-1.0 times the theoretical amount, and the amount of sulfuric acid added is 1.0-1.3 times the theoretical amount.

[0007] Preferably, the oxalic acid is added as follows: dissolve oxalic acid in water to form an oxalic acid aqueous solution with a mass fraction of 30%-50%, and slowly add the solution while stirring at room temperature.

[0008] Preferably, the filter residue obtained by the solid-liquid separation is washed so that the mass fraction of manganese in the residue is less than 5%.

[0009] Preferably, the washing is an online suction filtration washing on a Buchner funnel, which is rinsed three times in succession with pure water, dried, and sampled, and the washing water after solid-liquid separation is poured into a purification station.

[0010] Preferably, the solid-liquid separation method is Buchner funnel filtration.

[0011] Preferably, the method for purification in the back-end process is as follows: the manganese-containing filtrate is neutralized to remove iron, purified to remove calcium, magnesium and heavy metals, to obtain a qualified manganese sulfate solution, and then further synthesize a manganese-containing product.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention uses oxalic acid and sulfuric acid to leach manganese-containing oil sludge, which can efficiently utilize manganese resources in manganese-containing oil sludge, and the manganese recovery rate is higher than 98%, which is conducive to further preparing industrial-grade manganese sulfate products; it can effectively treat manganese-containing oil sludge in the production line, reduce the amount of slag, and reduce the pressure of the slag storage; 2. The method of the present invention can effectively recover a certain amount of fluorine in the slag, and subsequently recover the fluoride ions by extraction, turning waste into treasure, cleaning the environment and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0015] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0016] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0017] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0018] The oxalic acid used in the present invention is industrial-grade oxalic acid, and the sulfuric acid is industrial-grade sulfuric acid, with a main content of 98%.

[0019] The washing in the present invention is online suction filtration washing on a Buchner funnel, using pure water to rinse three times continuously, and then drying after being drained.

[0020] The solid-liquid separation method in the present invention is Buchner funnel filtration.

[0021] Embodiment 1: A method for leaching and recovering manganese-containing oil sludge using oxalic acid and sulfuric acid, such as Figure 1 , including the following steps: adding water to the manganese-containing sludge, stirring and beating, adding oxalic acid and sulfuric acid, leaching, solid-liquid separation, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product. The specific operation is as follows: (1) Take 223g of manganese-containing sludge and sample and test the main components. The specific data are as follows in Table 1: Table 1: Main components of manganese-containing sludge in Example 1

[0022] (2) According to Mn 4+ % content, calculate the dosage of oxalic acid, specifically add 1.0 times the theoretical amount at 65℃, and then calculate the dosage of concentrated sulfuric acid according to the Mn% content, specifically add 1.2 times the theoretical amount at 65℃; The method of adding oxalic acid is as follows: dissolving oxalic acid in water to form an oxalic acid aqueous solution with a mass fraction of 30%, and slowly adding the solution while stirring at room temperature; (3) The leaching temperature was maintained at 95°C for 4 hours. After the leaching was completed, solid-liquid separation was carried out, and the manganese-containing filtrate entered the back-end process (the main components are shown in Table 3). The filter residue was washed (to make the manganese content in the residue less than 5%) and dried to obtain residue manganese (the main components are shown in Table 2). The manganese-containing filtrate was neutralized to remove iron, and purified to remove calcium, magnesium and heavy metals to obtain manganese sulfate.

[0023] Table 2: Main components of manganese slag after drying

[0024] Table 3: Main indicators of leaching filtrate after solid-liquid separation

[0025] Embodiment 2: A method for leaching and recovering manganese-containing oil sludge using oxalic acid and sulfuric acid, such as Figure 1 , including the following steps: adding water to the manganese-containing sludge, stirring and beating, adding oxalic acid and sulfuric acid, leaching, solid-liquid separation, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product. The specific operation is as follows: (1) Take manganese-containing sludge and sample and test its main components. The specific data are as follows in Table 4: Table 4: Main components of manganese-containing sludge in Example 2

[0026] (2) According to Mn 4+% content, calculate the dosage of oxalic acid, specifically add 0.9 times the theoretical amount at room temperature, and then calculate the dosage of sulfuric acid according to the Mn% content, specifically add 1.0 times the theoretical amount at 65℃; The method of adding oxalic acid is as follows: dissolving oxalic acid in water to form an oxalic acid aqueous solution with a mass fraction of 50%, and slowly adding the solution while stirring at room temperature; (3) The leaching temperature was maintained at 65°C for 5 hours. After the leaching was completed, solid-liquid separation was carried out and the filtrate entered the back-end process (the main components are shown in Table 6). The filter residue was washed (so that the mass fraction of manganese in the residue was less than 5%) and dried to obtain residue manganese (the main components are shown in Table 5). The manganese-containing filtrate was neutralized to remove iron, and purified to remove calcium, magnesium and heavy metals to obtain manganese sulfate.

[0027] Table 5: Main components of manganese slag after drying

[0028] Table 6: Main indicators of leaching filtrate after solid-liquid separation

[0029] Comparative Example 1: The leaching test of manganese-containing oil sludge is carried out directly using sulfuric acid, including the following steps: adding water to the manganese-containing oil sludge, stirring and beating to mix, adding sulfuric acid, leaching, solid-liquid separation, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product. The specific operation is as follows: (1) Take manganese-containing sludge and sample and test its main components. The specific data are shown in Table 7: Table 7: Main components of manganese-containing sludge in Comparative Example 1

[0030] (2) Calculate the amount of sulfuric acid to be added based on the Mn% content, specifically 1.2 times the theoretical amount at 65°C; (3) The leaching temperature was maintained at 65°C for 5 hours. After the leaching was completed, solid-liquid separation was carried out and the filtrate entered the back-end process (the main components are shown in Table 9). The filter residue was washed and dried to obtain slag manganese (the main components are shown in Table 8). The manganese-containing filtrate was neutralized to remove iron, and purified to remove calcium, magnesium and heavy metals to obtain manganese sulfate.

[0031] Table 8: Main components of manganese slag after drying

[0032] Table 9: Main indicators of leaching filtrate after solid-liquid separation

[0033] Comparative Example 2: The leaching test of manganese-containing oil sludge is directly carried out using anhydrous ethanol and sulfuric acid, which includes the following steps: adding water to the manganese-containing oil sludge, stirring and beating to mix, first adding anhydrous ethanol, stirring to react, then adding sulfuric acid, leaching, solid-liquid separation, and the obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product. The specific operation is as follows: (1) Take manganese-containing sludge and sample and test its main components. The specific data are as follows in Table 10: Table 10: Main components of manganese-containing sludge in Comparative Example 2

[0034] (2) Add the above manganese-containing sludge into a beaker, add 1000 mL of water, add 100 mL of anhydrous ethanol, stir and react for 30 minutes, calculate the amount of sulfuric acid to be added according to the Mn% content, and specifically add 1.2 times the theoretical amount at 65°C; (3) The leaching temperature is maintained at 65°C for 5 hours. After the leaching is completed, solid-liquid separation is performed, and the filtrate enters the back-end process (the main components are shown in Table 12). The filter residue is washed and dried to obtain residue manganese (the main components are shown in Table 11); The manganese-containing filtrate is neutralized to remove iron, and purified to remove calcium, magnesium and heavy metals to obtain manganese sulfate.

[0035] Table 11: Main components of manganese slag after drying

[0036] Table 12: Main indicators of leaching filtrate after solid-liquid separation

[0037] Comparative Example 3: The leaching test of manganese-containing oil sludge was conducted directly using pyrite and sulfuric acid, including the following steps: adding water to the manganese-containing oil sludge, stirring and beating, first adding pyrite, then adding sulfuric acid, leaching, solid-liquid separation, and the obtained manganese-containing filtrate entered the back-end process for purification to obtain a manganese-containing product. The specific operation is as follows: (1) Take manganese-containing sludge and sample and test its main components. The specific data are as follows in Table 13: Table 13: Main components of manganese-containing sludge in Comparative Example 3

[0038] (2) Add the above manganese-containing sludge into a beaker, add 1000 mL of water, and adjust the Mn 4+ %Calculate the dosage of pyrite and add it at 1.2 times. Calculate the dosage of sulfuric acid according to the Mn% content, specifically add 1.2 times the theoretical amount at 65℃; (3) The leaching temperature was maintained at 65°C for 5 hours. After the leaching was completed, solid-liquid separation was performed, and the filtrate entered the back-end process (the main components are shown in Table 15). The filter residue was washed and dried to obtain slag manganese (the main components are shown in Table 14); The manganese-containing filtrate is neutralized to remove iron, and purified to remove calcium, magnesium and heavy metals to obtain manganese sulfate.

[0039] Table 14: Main components of manganese slag after drying

[0040] Table 15: Main indicators of leaching filtrate after solid-liquid separation

[0041] From the analysis of the above comparative examples, considering that the manganese-containing sludge contains a large amount of organic components, anhydrous ethanol is used for synergistic leaching, but the leaching efficiency is limited and the leaching rate cannot be significantly improved; considering that the manganese-containing sludge contains some high-priced manganese, pyrite is used for reduction leaching, but the leaching rate is only 75.83%.

[0042] In summary, the present invention uses oxalic acid and sulfuric acid to leach and recover manganese-containing oil sludge, which can effectively recover manganese resources in organic phase slag, and the manganese recovery rate is higher than 98%, which is conducive to further preparing industrial-grade manganese sulfate products; it can effectively treat manganese-containing oil sludge in the production line, reduce the amount of slag, and reduce the pressure of the slag storage; it can also effectively recover a certain amount of fluorine in the slag, and subsequently recover fluoride ions through extraction, turning waste into treasure, cleaning the environment, reducing costs, and increasing the production efficiency of manganese sulfate products.

Claims

1. A method for leaching and recovering manganese-containing oil sludge using oxalic acid and sulfuric acid, characterized in that: The method comprises the following steps: adding water to the manganese-containing oil sludge, stirring and beating the sludge to mix well, adding oxalic acid and sulfuric acid to carry out leaching, and performing solid-liquid separation. The obtained manganese-containing filtrate enters the back-end process for purification to obtain a manganese-containing product.

2. The method according to claim 1, characterized in that The manganese-containing oil sludge is manganese-containing oil sludge produced in the manganese sulfate extraction section, and contains manganese oxide.

3. The method according to claim 1, characterized in that The oxalic acid is industrial grade oxalic acid; the sulfuric acid is industrial grade sulfuric acid.

4. The method according to claim 1, characterized in that The amount of oxalic acid added is 0.7-1.0 times the theoretical amount, and the amount of sulfuric acid added is 1.0-1.3 times the theoretical amount.

5. The method according to claim 1, characterized in that The oxalic acid is added in the following manner: dissolve oxalic acid in water to form an oxalic acid aqueous solution with a mass fraction of 30%-50%, and then slowly add the solution while stirring at room temperature.

6. The method according to claim 1, characterized in that The filter residue obtained by the solid-liquid separation is washed so that the mass fraction of manganese in the residue is less than 5%.

7. The method according to claim 6, characterized in that The washing is performed by online suction filtration washing on a Buchner funnel, using pure water to rinse three times in a row, and then drying after being drained.

8. The method according to claim 1, characterized in that The solid-liquid separation method is Buchner funnel filtration.

9. The method according to any one of claims 1 to 8, characterized in that The method for the back-end purification process is as follows: the manganese-containing filtrate is neutralized to remove iron, purified to remove calcium, magnesium and heavy metals, to obtain a qualified manganese sulfate solution, and then further synthesize a manganese-containing product.

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