A harmless treatment method of manganese slag

Abstract

The present application relates to the field of industrial waste residue treatment, and particularly relates to a harmless treatment method of manganese residue. The harmless treatment method of the manganese residue comprises filter pressing of the manganese residue, pretreatment of the manganese residue and solidification treatment. The pretreatment of the manganese residue is achieved by adding a manganese solidification agent, an ammonia-nitrogen solidification agent and an alkali activator into the manganese residue. The dosages of the manganese residue, the manganese solidification agent, the ammonia-nitrogen solidification agent and the alkali activator are respectively 89% to 94.9% of the manganese residue, 4% to 6.5% of the manganese solidification agent, 1% to 3.5% of the ammonia-nitrogen solidification agent and 0.1% to 1% of the alkali activator. The manganese solidification agent is composed of the following components in parts by weight: 10 to 15 parts of high-silicon aluminum solid waste, 0.5 to 5 parts of graphene nanosheet and 2 to 5 parts of CaO. The ammonia-nitrogen solidification agent is anhydrous phosphogypsum in parts by weight of 6 to 14. The harmless treatment method of the manganese residue has high solidification efficiency and high compressive strength of the solidified body, reduces the damage of harmful substances in the manganese residue to the environment, and realizes resource utilization of the high-silicon aluminum solid waste and green environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial waste residue treatment, and particularly relates to a harmless treatment method of manganese residue. BACKGROUND

[0002] Manganese residue refers to industrial waste residue formed in the process of producing electrolytic manganese dioxide, electrolytic manganese and manganese sulfate, and the main components of the manganese residue are calcium sulfate (of which the content of sulfur trioxide is 18% to 22%), manganese (of which the content is about 2%) and silicon dioxide (of which the content is about 21%), in addition, the manganese residue also contains a small amount of aluminum oxide and iron oxide, and a certain amount of ammonia nitrogen in electrolytic manganese residue, which belongs to general solid waste. At present, the manganese residue is facing the situation of large stockpiling, rising production but less than 10% comprehensive utilization rate, and the main treatment method of the manganese residue is still stacking and landfill, and the harm to the environment cannot be ignored. First, heavy metal ions such as lead and chromium in the manganese residue can enter the soil, groundwater and surface water through leakage and overflow, and have toxic effects on plants, soil organisms and aquatic organisms, and the large amount of stacking of the manganese residue can also cause soil pollution, reduce soil fertility and affect plant growth; secondly, the chemical substances in the manganese residue can enter the water body through washing, rainwater washing and other ways, causing water pollution, which can have toxic effects on aquatic organisms and affect the ecological balance of the water body, in addition, harmful substances in the process of treatment and transportation of the manganese residue can also affect the air quality around; finally, the toxic chemical substances in the manganese residue are absorbed by organisms and gradually enriched in the food chain, which can cause the organisms in the high-level food chain to be exposed to high-concentration harmful substances, and the harm to human beings or wild animals can be accumulated day by day.

[0003] Currently, the main recovery and treatment methods of manganese slag include physical, chemical methods or both. Physical methods include screening, magnetic separation and other means. Chemical methods mainly use solidification technology to convert manganese and other heavy metals in manganese slag into stable forms or fix them in dense inclusions with certain strength, so as to reduce the migration of manganese and other heavy metals in manganese slag, reduce or eliminate the pollution risk of manganese slag to the environment. Common manganese slag solidifying agents can be divided into chemical reagents and other solid wastes, such as quicklime, cement, soluble phosphate, silicate and the like. However, the existing treatment technology still has a series of problems, which limits the effective treatment and resource utilization of manganese slag, such as the emission of heavy metals, which is difficult to completely remove from manganese slag by traditional physical treatment methods, resulting in potential harm to the environment. For chemical treatment method, the selection of solidifying agent and the stability of solidification product become the main problems. The selection of solidifying agent not only has good solidification effect on manganese slag, but also avoids the generation of secondary pollution. Some solidification products may deteriorate or decompose during long-term storage or under external conditions, resulting in the release of harmful substances and weakening the solidification effect. In addition, manganese slag has high viscosity, poor dispersibility, uneven particle distribution and difficulty in uniform mixing with other additives. Therefore, it is necessary to develop an efficient and economical solidifying agent for the pretreatment of manganese slag to ensure long-term stable storage of manganese slag and avoid secondary pollution. SUMMARY

[0004] To solve the above technical problems, the present application provides a harmless treatment method for manganese slag, which comprises the following processes: pressure filtration of manganese slag, pretreatment of manganese slag and solidification treatment. The pretreatment of manganese slag is achieved by adding manganese solidifying agent, ammonia-nitrogen solidifying agent and alkali activator into the manganese slag. The most important thing in the solidification of manganese slag is the formation of an alkaline environment. The high-silicon aluminum solid waste and CaO used in the present application are both alkaline in water and have good solidification effect on heavy metals in manganese slag. The addition of graphene nanosheets helps to promote the formation of gel structure. Anhydrous phosphogypsum as an ammonia-nitrogen solidifying agent can convert NH4 + -N into struvite, which has good solidification and stabilization effect on manganese slag, reduces the damage of soluble Mn 2+ , heavy metal ions and NH4 + -N in manganese slag to the environment, and realizes the harmless treatment of manganese slag.

[0005] To achieve the above purpose, the following technical scheme is adopted:

[0006] A harmless treatment method for manganese slag, comprising the following processes: pressure filtration of manganese slag, pretreatment of manganese slag and solidification treatment.

[0007] The manganese slag pretreatment is achieved by adding a manganese solidifying agent, an ammonia-nitrogen solidifying agent and an alkali activator into the manganese slag, and the mass fractions of the manganese slag, the manganese solidifying agent, the ammonia-nitrogen solidifying agent and the alkali activator are 89% to 94.9%, 4% to 6.5%, 1% to 3.5% and 0.1% to 1%, respectively;

[0008] The manganese solidifying agent is composed of the following components by weight: 10 to 15 parts of high-silicon aluminum solid waste, 0.5 to 5 parts of graphene nanosheet, and 2 to 5 parts of CaO, wherein the high-silicon aluminum solid waste is one of coal gangue and aluminum ash, the CaO is an analytical reagent with a purity of 98% by weight, and the graphene nanosheet has a sheet diameter of 5 to 10 microns, a thickness of 3 to 10 nanometers, and a specific surface area of 30 to 31 m 2 / g.

[0009] The ammonia-nitrogen solidifying agent is anhydrous phosphogypsum with a particle size of 10 to 50 microns, and the addition amount is 6 to 14 parts by weight.

[0010] The alkali activator is composed of the following raw materials in a molar ratio of NaOH:KOH = 1:1, wherein NaOH and KOH are both granular analytical reagents with a purity of 96%.

[0011] Further, the preparation of the manganese solidifying agent includes the following steps:

[0012] Q1, a dispersant is added to 1L of deionized water in an amount of 0.5g / L, stirred and dissolved, the stirring speed is 100 to 300rpm, the stirring time is 10 to 20min, graphene nanosheet is added and ultrasonic dispersed for 15 to 25min until the graphene nanosheet is uniformly dispersed, and a graphene nanosheet dispersion liquid is obtained;

[0013] Q2, the high-silicon aluminum solid waste is ground and passed through a 200-mesh sieve for use, and a high-silicon aluminum solid waste powder is obtained

[0014] Q3, the graphene nanosheet dispersion liquid obtained in step Q1, the high-silicon aluminum solid waste powder obtained in step Q2 and CaO are taken according to the formula proportion respectively, and the three parts together constitute the manganese solidifying agent, which is used by mixing with the manganese slag.

[0015] Preferably, the dispersant in step Q1 is polyvinylpyrrolidone with an average molecular weight of 58000 and a density of 1.14g / cm 3 .

[0016] Further, the preparation method of the ammonia-nitrogen solidifying agent is as follows: anhydrous phosphogypsum is taken according to the formula proportion, ground and passed through a 200-mesh sieve for use, and an anhydrous phosphogypsum powder is obtained, which is the ammonia-nitrogen solidifying agent.

[0017] Further, the alkali activator is prepared by dissolving KOH and NaOH in deionized water in a certain proportion.

[0018] Further, the pressure filtration of the manganese residue comprises the following steps:

[0019] P1, the manganese residue is stirred and mixed to ensure uniform distribution of particles, then loaded into a pressure filter, the pressure filter is pressurized, the pressure is 2-3 MPa, the time is 1-2 h, after the pressure filtration is completed, the filtrate and the solid particles retained on the filter medium are obtained;

[0020] P2, the filtrate and the solid particles retained on the filter medium obtained in step P1 are collected respectively, and the solid particles retained on the filter medium are the pressure filtration manganese residue.

[0021] Further, the manganese residue pretreatment comprises the following steps:

[0022] S1, the pressure filtration manganese residue is transferred into a dispersing mixer by a forklift, an ammonia nitrogen curing agent is added, stirring treatment is performed for 10-30 min, the stirring speed is 200-400 rpm, and a first-stage mixture is obtained;

[0023] S2, the manganese curing agent is added to the first-stage mixture obtained in step S1, the addition is performed in two steps, graphene nanosheet dispersion liquid is first added, stirring treatment is performed for 10-30 min, the stirring speed is 200-400 rpm, then the high-silicon aluminum solid waste with uniform particle size and CaO are jointly added, stirring treatment is performed for 20-30 min, the stirring speed is 200-400 rpm, and a second-stage mixture is obtained;

[0024] S3, the alkali activator is added to the second-stage mixture obtained in step S2, the addition is performed in three times according to the total amount, the ratio of each time is 5:3:2, the first time and the second time are separated by 10 min of stirring, the stirring speed is 200-300 rpm, after the third time of addition, stirring is performed for 1-2 h, the stirring speed is 200-300 rpm, until mixing is uniform, and a third-stage mixture is obtained;

[0025] S4, after the second-stage mixture obtained in step S3 is transported to the ground by a belt, the second-stage mixture is transferred to a stacking site, and a manganese residue to be cured is obtained.

[0026] Further, the curing treatment is one of underground filling and open-air backfilling.

[0027] Preferably, the operation of the underground filling is as follows: the manganese residue to be cured is transferred to a mud pool beside a well mouth, water is added to the mud pool to stir the manganese residue to be cured into a thin mud slurry, the mud slurry pump is used to transport the manganese residue to be cured to the underground through a pipeline, and the manganese residue to be cured is completely cured after 28 days, and a harmless manganese residue curing body is obtained.

[0028] Preferably, the operation of the open-air backfilling is as follows: the manganese residue to be cured is transferred to a backfilling site, and is mechanically compacted, and the manganese residue to be cured is completely cured after 28 days, and a harmless manganese residue curing body is obtained.

[0029] The beneficial effects obtained by the present application are as follows:

[0030] The harmless treatment method of the manganese slag provided by the present application comprises filter pressing of the manganese slag, pretreatment of the manganese slag and solidification treatment, and the key of the process is the pretreatment of the manganese slag, in which a manganese solidification agent, an ammonia-nitrogen solidification agent and an alkali activator are added to the manganese slag to achieve the purposes of constructing an alkaline environment, solidifying and stabilizing soluble Mn 2+ , NH4 + -N and the like. First, the ammonia-nitrogen solidification agent is anhydrous phosphogypsum, which can solidify NH4 + -N in the form of struvite and simultaneously solidify and stabilize a part of heavy metals such as soluble Mn 2+ , and the solidification of NH4 + -N in advance can avoid the conversion of ammonia-nitrogen in the manganese slag into free ammonia after the addition of the manganese solidification agent, and the exothermic reaction of CaO with water to cause the free ammonia to be converted into gaseous ammonia and released into the environment to cause harm to the environment; second, the manganese solidification agent is added, and the addition of the manganese solidification agent is in two steps, i.e., adding graphene nanosheet dispersion liquid first and then adding high-silicon aluminum solid waste and CaO together, to solidify and stabilize soluble Mn 2+ in the system, and the main components of the high-silicon aluminum solid waste are alumina and silica, which can form gel materials with the manganese slag in a low-temperature alkaline environment in cooperation with CaO and the alkali activator to adsorb and encapsulate heavy metals, thereby achieving the purpose of solidification, and the graphene nanosheet as a component of the solidification agent participates in the solidification treatment, and due to the nucleation site effect of the graphene nanosheet, the generation and increase of C-(A)-S-H gel in the harmless manganese slag solidification body are promoted, and meanwhile, the graphene nanosheet has a filling and optimization effect on pores, so that the structure of the harmless manganese slag solidification body is more compact; finally, the mechanical strength of the graphene nanosheet itself can improve the compressive strength of the harmless manganese slag solidification body, and the graphene nanosheet also has a certain adsorption effect on heavy metal ions, which is helpful to the improvement of the solidification efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments or the examples of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments and the comparative examples. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor under the premise of the drawings.

[0032] Figure 1 It is a flowchart of the harmless treatment of manganese slag.

[0033] Figure 2 It is the Mn 2+ and NH4 +a leaching concentration histogram of the manganese slag;

[0034] Figure 3 a compressive strength histogram of the harmless manganese slag solidified body obtained in each example and comparative example;

[0035] Figure 4 a pH broken line graph of the harmless manganese slag solidified body obtained in each example and comparative example. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The described embodiments are 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 a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0037] Example 1

[0038] A harmless treatment method of manganese slag, comprising the following processes: pressure filtration of manganese slag, manganese slag pretreatment, solidification treatment.

[0039] The manganese slag pretreatment is achieved by adding a manganese solidification agent, an ammonia-nitrogen solidification agent and an alkali activator into the manganese slag, and the mass fractions of the manganese slag, the manganese solidification agent, the ammonia-nitrogen solidification agent and the alkali activator are 94.9%, 4%, 1% and 0.1% respectively.

[0040] The preparation of the manganese solidification agent comprises the following steps:

[0041] Q1, polyvinylpyrrolidone is added into 1L deionized water in an amount of 0.5g / L, stirred and dissolved, the stirring speed is 100rpm, the stirring time is 10min, 3 parts of graphene nanosheet are added and ultrasonically dispersed for 15min until the graphene nanosheet is uniformly dispersed, to obtain a graphene nanosheet dispersion liquid, the polyvinylpyrrolidone has an average molecular weight of 58000 and a density of 1.14g / cm 3 , the graphene nanosheet has a sheet diameter of 10μm and a thickness of 5nm, and a specific surface area of 30.15m 2 / g;

[0042] Q2, 12.5 parts of coal gangue are ground and passed through a 200-mesh sieve to obtain coal gangue powder;

[0043] Q3, the graphene nanosheet dispersion liquid obtained in step Q1, the coal gangue powder obtained in step Q2 and 3 parts of CaO are taken together to form a manganese solidification agent, which is used by mixing with the manganese slag.

[0044] The preparation method of the ammonia-nitrogen curing agent is as follows: 9.5 parts of anhydrous phosphogypsum with a particle size of 40 μm are ground and then passed through a 200-mesh sieve to obtain anhydrous phosphogypsum powder, which is the ammonia-nitrogen curing agent.

[0045] The alkali activator is prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1, and the NaOH and KOH are both granular analytical reagents with a purity of 96%.

[0046] The pressure filtration of the manganese slag includes the following steps:

[0047] P1, the manganese slag is stirred and mixed to ensure uniform particle distribution, then loaded into a pressure filter, the pressure filter is pressurized to 2 MPa, and the pressure is maintained for 1 h, after the pressure filtration is completed, a filtrate and solid particles retained on the filter medium are obtained;

[0048] P2, the filtrate and the solid particles retained on the filter medium obtained in step P1 are collected respectively, and the solid particles retained on the filter medium are the pressure-filtered manganese slag.

[0049] The manganese slag pretreatment includes the following steps:

[0050] S1, the pressure-filtered manganese slag is transferred into a dispersing mixer by a forklift, the ammonia-nitrogen curing agent is added, and stirring is performed for 10 min at a stirring speed of 200 rpm to obtain a first-stage mixture;

[0051] S2, the manganese curing agent is added to the first-stage mixture obtained in step S1, and the addition is performed in two steps, graphene nanosheet dispersion liquid is first added, stirring is performed for 10 min at a stirring speed of 200 rpm, and then uniformly sized high-silicon aluminum solid waste and CaO are jointly added, stirring is performed for 20 min at a stirring speed of 200 rpm to obtain a second-stage mixture;

[0052] S3, the alkali activator is added to the second-stage mixture obtained in step S2, and the addition is performed in three times according to the total amount, the ratio of each time is 5:3:2, the first and second times are separated by 10 min of stirring at a stirring speed of 200 rpm, and after the third time, stirring is performed for 1 h at a stirring speed of 200 rpm until the mixture is uniformly mixed to obtain a third-stage mixture;

[0053] S4, the second-stage mixture obtained in step S3 is dropped onto the ground by belt transportation and then transferred to a stacking site to obtain the manganese slag to be cured.

[0054] The curing treatment is underground filling, the manganese slag to be cured is transferred to a mud pool beside a well mouth, water is added to the pool to stir the manganese slag to be cured into a dilute mud slurry, the mud slurry pump is used to transport the manganese slag to be cured to the underground through a pipeline, and the manganese slag to be cured is completely cured after 28 days to obtain a harmless manganese slag cured body.

[0055] Example 2:

[0056] A harmless treatment method of manganese slag, comprising the following processes: filter pressing manganese slag, manganese slag pretreatment, solidification treatment;

[0057] Wherein, the manganese slag pretreatment is achieved by adding manganese solidification agent, ammonia nitrogen solidification agent, alkali activator in the manganese slag, the mass fraction of the amount of manganese slag, manganese solidification agent, ammonia nitrogen solidification agent, alkali activator is respectively: manganese slag 93.8%, manganese solidification agent 4.5%, ammonia nitrogen solidification agent 1.5%, alkali activator 0.2%.

[0058] The preparation of manganese solidification agent comprises the following steps:

[0059] Q1, polyvinylpyrrolidone is added to 1L deionized water, the amount is 0.5g / L, stirring and dissolving, stirring speed 200rpm, stirring time 15min, adding 3 parts of graphene nanosheet and ultrasonic dispersion for 20min to make the graphene nanosheet dispersed uniformly, obtaining graphene nanosheet dispersion, polyvinylpyrrolidone, average molecular weight is 58000, density is 1.14g / cm 3 , the flake diameter of graphene nanosheet is 10μm, the thickness is 5nm, the specific surface area is 30.15m 2 / g;

[0060] Q2, take 12.5 parts of coal gangue after grinding and pass through 200 mesh sieve for use, obtaining coal gangue powder;

[0061] Q3, take the graphene nanosheet dispersion obtained in step Q1, the coal gangue powder obtained in step Q2 and 3 parts of CaO, the three parts together constitute the manganese solidification agent, which is mixed with manganese slag when used.

[0062] The preparation method of ammonia nitrogen solidification agent is as follows: take 9.5 parts of anhydrous phosphogypsum with particle size of 40μm, grind and pass through 200 mesh sieve for use, obtaining anhydrous phosphogypsum powder, which is the ammonia nitrogen solidification agent.

[0063] The alkali activator is prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1, NaOH and KOH are both granular analytical reagent with purity of 96%.

[0064] Filter pressing manganese slag comprises the following steps:

[0065] P1, mix manganese slag by stirring, ensure uniform distribution of particles, then load into filter press, pressurize the filter press, pressure is 2.5MPa, time is 1.5h, after filter pressing is completed, obtain filtrate and solid particles retained on the filter medium;

[0066] P2, collect the filtrate and the solid particles retained on the filter medium obtained in step P1 respectively, the solid particles retained on the filter medium are the filter pressed manganese slag.

[0067] The manganese slag pretreatment comprises the following steps:

[0068] S1, the filter press manganese slag is transported into the dispersing mixer by the forklift, the ammonia nitrogen curing agent is added, the stirring treatment is 20 min, the stirring speed is 300 rpm, and the first stage mixture is obtained;

[0069] S2, the manganese curing agent is added to the first stage mixture obtained in step S1, and is added in two steps, the graphene nanosheet dispersion liquid is first added, stirring treatment is 15 min, the stirring speed is 300 rpm, and then the high-silicon aluminum solid waste and CaO with uniform particle size are added together, stirring treatment is 25 min, the stirring speed is 300 rpm, and the second stage mixture is obtained;

[0070] S3, the alkali activator is added to the second stage mixture obtained in step S2, and is added in three times according to the total amount, the ratio of each time is 5:3:2, the stirring interval between the first time and the second time is 10 min, the stirring speed is 200 rpm, the stirring speed is 250 rpm after the third time, and stirring is carried out for 1.5 h, until the mixture is uniform, and the third stage mixture is obtained;

[0071] S4, the second stage mixture obtained in step S3 is transported to the stacking site after falling on the ground by the belt, and the manganese slag to be cured is obtained.

[0072] The curing treatment is underground filling, the manganese slag to be cured is transported to the mud pool beside the well mouth, water is added in the pool to stir the manganese slag to be cured into a thin mud slurry, the mud slurry pump is used to transport the manganese slag to be cured to the underground through the pipeline, and the manganese slag to be cured is completely cured after 28 days, and the harmless manganese slag curing body is obtained.

[0073] Example 3:

[0074] A harmless treatment method of manganese slag, comprising the following processes: filter press manganese slag, manganese slag pretreatment, and curing treatment.

[0075] The manganese slag pretreatment is achieved by adding a manganese curing agent, an ammonia nitrogen curing agent, and an alkali activator in the manganese slag, and the mass fractions of the manganese slag, the manganese curing agent, the ammonia nitrogen curing agent, and the alkali activator are 92.6%, 5%, 2%, and 0.4%, respectively.

[0076] The preparation of the manganese curing agent comprises the following steps:

[0077] Q1, polyvinylpyrrolidone was added to 1 L of deionized water, the amount was 0.5 g / L, stirring and dissolving, stirring speed 300 rpm, stirring time 20 min, 3 parts of graphene nanosheet was added and ultrasonic dispersed for 25 min until the graphene nanosheet was uniformly dispersed, to obtain graphene nanosheet dispersion, polyvinylpyrrolidone, average molecular weight was 58000, density was 1.14 g / cm 3 , the flake diameter of graphene nanosheet was 10 μm, the thickness was 5 nm, the specific surface area was 30.15 m 2 / g;

[0078] Q2, 12.5 parts of coal gangue was ground and passed through a 200 mesh sieve for use, to obtain coal gangue powder;

[0079] Q3, the graphene nanosheet dispersion obtained in step Q1, the coal gangue powder obtained in step Q2 and 3 parts of CaO were taken together to form a manganese solidifying agent, which was mixed with manganese residue when used.

[0080] The preparation method of the ammonia-nitrogen solidifying agent is as follows: 9.5 parts of anhydrous phosphogypsum with a particle size of 40 μm was ground and passed through a 200 mesh sieve for use, to obtain anhydrous phosphogypsum powder, which was the ammonia-nitrogen solidifying agent.

[0081] The alkali activator was prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1, both NaOH and KOH were granular analytical reagents with a purity of 96%.

[0082] The pressure filtration of manganese residue includes the following steps:

[0083] P1, the manganese residue was stirred and mixed to ensure uniform distribution of particles, then loaded into a pressure filter, the pressure filter was pressurized, the pressure was 3 MPa, the time was 2 h, after the pressure filtration was completed, the filtrate and the solid particles retained on the filter medium were obtained;

[0084] P2, the filtrate and the solid particles retained on the filter medium obtained in step P1 were collected respectively, the solid particles retained on the filter medium were the pressure filtration manganese residue.

[0085] The pretreatment of manganese residue includes the following steps:

[0086] S1, the pressure filtration manganese residue was transferred into a dispersing mixer by a forklift, the ammonia-nitrogen solidifying agent was added, and stirring treatment was carried out for 30 min at a stirring speed of 400 rpm, to obtain a first-stage mixture;

[0087] S2, the manganese solidifying agent is added to the first-stage mixture obtained in step S1, the graphene nanosheet dispersion liquid is added first, stirring treatment is performed for 20 min at a stirring speed of 400 rpm, and then the high-silicon aluminum solid waste and CaO with uniform particle size are added together, stirring treatment is performed for 30 min at a stirring speed of 400 rpm, to obtain a second-stage mixture;

[0088] S3, the alkali activator is added to the second-stage mixture obtained in step S2, the alkali activator is added in three portions according to the total amount, the proportion of each addition is 5:3:2, the first addition and the second addition are separated by 10 min of stirring at a stirring speed of 300 rpm, and after the third addition, stirring is performed for 2 h at a stirring speed of 300 rpm until the mixture is uniform, to obtain a third-stage mixture;

[0089] S4, after the second-stage mixture obtained in step S3 is dropped by belt transportation, the second-stage mixture is transported to a storage site, to obtain the manganese slag to be solidified.

[0090] The solidification treatment is underground filling, the manganese slag to be solidified is transported to a mud pool beside a well mouth, water is added to the mud pool to stir the manganese slag to be solidified into a dilute mud slurry, the mud slurry pump is used to transport the manganese slag to be solidified to the underground through a pipeline, and the manganese slag to be solidified is completely solidified after 28 days, to obtain a harmless manganese slag solidification body.

[0091] Example 4:

[0092] A harmless treatment method of manganese slag, comprising the following processes: filter pressing of manganese slag, manganese slag pretreatment, and solidification treatment.

[0093] The manganese slag pretreatment is achieved by adding a manganese solidifying agent, an ammonia-nitrogen solidifying agent, and an alkali activator to the manganese slag, and the mass fractions of the manganese slag, the manganese solidifying agent, the ammonia-nitrogen solidifying agent, and the alkali activator are 91.4%, 5.5%, 2.5%, and 0.6%, respectively.

[0094] The preparation of the manganese solidifying agent comprises the following steps:

[0095] Q1, polyvinylpyrrolidone is added to 1 L of deionized water, the amount of polyvinylpyrrolidone added is 0.5 g / L, stirring and dissolving are performed at a stirring speed of 200 rpm for 15 min, 3 parts of graphene nanosheets are added and ultrasonic dispersion is performed for 20 min until the graphene nanosheets are uniformly dispersed, to obtain a graphene nanosheet dispersion liquid, the average molecular weight of the polyvinylpyrrolidone is 58000, and the density of the polyvinylpyrrolidone is 1.14 g / cm 3 The flake diameter of the graphene nanosheets is 10 μm, the thickness of the graphene nanosheets is 5 nm, and the specific surface area of the graphene nanosheets is 30.15 m 2 / g;

[0096] Q2, 12.5 parts of coal gangue is ground and then sieved through a 200-mesh sieve to obtain a coal gangue powder;

[0097] Q3, the graphene nanosheet dispersion liquid obtained in step Q1, the coal gangue powder obtained in step Q2 and 3 parts of CaO are taken together to form a manganese solidifying agent, which is used by mixing with the manganese residue.

[0098] The preparation method of the ammonia-nitrogen solidifying agent is as follows: 9.5 parts of anhydrous phosphogypsum with a particle size of 40 μm are ground and sieved through a 200-mesh sieve to obtain anhydrous phosphogypsum powder, which is the ammonia-nitrogen solidifying agent.

[0099] The alkali activator is prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1, and the NaOH and KOH are both granular analytical reagents with a purity of 96%.

[0100] The pressure filtration of the manganese residue, the manganese residue pretreatment and the solidification treatment method and steps are consistent with those of Example 2.

[0101] Example 5:

[0102] A harmless treatment method of manganese residue, comprising the following processes: pressure filtration of manganese residue, manganese residue pretreatment, solidification treatment;

[0103] The manganese residue pretreatment is achieved by adding a manganese solidifying agent, an ammonia-nitrogen solidifying agent and an alkali activator into the manganese residue, and the mass fractions of the manganese residue, the manganese solidifying agent, the ammonia-nitrogen solidifying agent and the alkali activator are 90.2%, 6%, 3% and 0.8%, respectively.

[0104] The preparation of the manganese solidifying agent comprises the following steps:

[0105] Q1, polyvinylpyrrolidone is added to 1 L of deionized water at an amount of 0.5 g / L, stirred and dissolved at a stirring speed of 200 rpm for 15 min, 3 parts of graphene nanosheet are added and ultrasonically dispersed for 20 min until the graphene nanosheet is uniformly dispersed to obtain a graphene nanosheet dispersion liquid, the polyvinylpyrrolidone has an average molecular weight of 58000 and a density of 1.14 g / cm 3 , the graphene nanosheet has a sheet diameter of 10 μm, a thickness of 5 nm and a specific surface area of 30.15 m 2 / g;

[0106] Q2, 12.5 parts of coal gangue are ground and sieved through a 200-mesh sieve to obtain a coal gangue powder;

[0107] Q3, the graphene nanosheet dispersion liquid obtained in step Q1, the coal gangue powder obtained in step Q2 and 3 parts of CaO are taken together to form a manganese solidifying agent, which is used by mixing with the manganese residue.

[0108] The preparation method of the ammonia-nitrogen curing agent is as follows: 9.5 parts of anhydrous phosphogypsum with a particle size of 40 μm is ground and sieved through a 200-mesh sieve to obtain anhydrous phosphogypsum powder, which is the ammonia-nitrogen curing agent.

[0109] The alkali activator is prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1, and the NaOH and KOH are both granular analytical reagents with a purity of 96%.

[0110] The pressure filtration of the manganese slag, the manganese slag pretreatment, and the solidification treatment method and steps are consistent with those of Example 2.

[0111] Example 6:

[0112] A harmless treatment method of manganese slag, comprising the following processes: pressure filtration of manganese slag, manganese slag pretreatment, and solidification treatment.

[0113] The manganese slag pretreatment is achieved by adding a manganese curing agent, an ammonia-nitrogen curing agent, and an alkali activator to the manganese slag, and the mass fractions of the manganese slag, the manganese curing agent, the ammonia-nitrogen curing agent, and the alkali activator are 89%, 6.5%, 3.5%, and 1%, respectively.

[0114] The preparation of the manganese curing agent includes the following steps:

[0115] Q1, polyvinylpyrrolidone is added to 1 L of deionized water at a dosage of 0.5 g / L, stirred and dissolved, the stirring speed is 200 rpm, the stirring time is 15 min, 3 parts of graphene nanosheet are added and ultrasonically dispersed for 20 min until the graphene nanosheet is uniformly dispersed, to obtain a graphene nanosheet dispersion liquid, the polyvinylpyrrolidone has an average molecular weight of 58000 and a density of 1.14 g / cm 3 , the graphene nanosheet has a sheet diameter of 10 μm and a thickness of 5 nm, and a specific surface area of 30.15 m 2 / g;

[0116] Q2, 12.5 parts of coal gangue is ground and sieved through a 200-mesh sieve to obtain coal gangue powder;

[0117] Q3, the graphene nanosheet dispersion liquid obtained in step Q1, the coal gangue powder obtained in step Q2, and 3 parts of CaO are mixed to form a manganese curing agent, which is used by mixing with the manganese slag.

[0118] The preparation method of the ammonia-nitrogen curing agent is as follows: 9.5 parts of anhydrous phosphogypsum with a particle size of 40 μm is ground and sieved through a 200-mesh sieve to obtain anhydrous phosphogypsum powder, which is the ammonia-nitrogen curing agent.

[0119] The alkali activator was prepared by dissolving KOH and NaOH in deionized water at a molar ratio of 1:1. Both NaOH and KOH were granular analytical reagents with a purity of 96%.

[0120] The pressure filtration of manganese slag, pretreatment of manganese slag, and solidification treatment method and steps were consistent with Example 2.

[0121] Comparative Example 1:

[0122] Based on Example 4, the difference is that graphene nanosheets are not added in the preparation process of the manganese solidification agent, and the remaining preparation steps and process steps are consistent with Example 4.

[0123] Comparative Example 2:

[0124] Based on Example 4, the difference is that coal gangue is not added in the preparation process of the manganese solidification agent, and the remaining preparation steps and process steps are consistent with Example 4.

[0125] Experimental Example:

[0126] 1. Leaching experiment:

[0127] According to the provisions of HJ 557-2020, take the harmless manganese slag solidification body obtained from each example and comparative example sample, crush it to a particle size that can pass through a 3mm aperture sieve, and then take 100g of each sample and dry it in a pre-dried constant weight container at 105°C until constant weight. Then take 50g and place it in a 1L leaching bottle with pure water as the leaching agent, with a liquid-solid ratio of 10:1. Shake it on a horizontal shaker at a frequency of 110 times / min at room temperature for 8h, and then take the supernatant after 16h of standing and pass it through a 0.45μm filter membrane into a 50mL centrifuge tube. Prepare three sets of parallel samples for each sample to eliminate random errors.

[0128] Mn 2+ , Ni 2+ content in the leaching solution was determined by ICP, and the elemental content of As, Pb, Cd, Cu, and Cr was determined by IPC-MS. NH4 + According to HJ 535-2009, use a visible spectrophotometer and an ammonia nitrogen distillation device to determine.

[0129] The leaching concentrations of Mn 2+ and NH4 + after the leaching experiment of each example and comparative example sample are shown in Table 1 and Figure 2 Table 2 shows the elemental content of Zn, As, Pb, Cd, Cu, and Cr in the leaching solution of the leaching experiment of Example 4 sample.

[0130] 2. Compressive strength of solidification body:

[0131] The compressive strength of three parallel samples of the solidified body of the harmless manganese slag obtained in different embodiments and comparative examples was measured by a compressive strength testing machine. When the compressive strength of the three parallel samples all met the error requirement, the average value was taken as the representative value of the compressive strength of the sample.

[0132] The compressive strength of the solidified body of the harmless manganese slag obtained in different embodiments and comparative examples is shown in Table 3 and Figure 3 .

[0133] 3. pH of the solidified body:

[0134] The pH was measured by a pH meter, and the model used was pHs-3C.

[0135] The pH of the solidified body of the harmless manganese slag obtained in different embodiments and comparative examples is shown in Table 3 and Figure 4 .

[0136] 4. Component detection of the solidified body of the harmless manganese slag:

[0137] The sample of the solidified body of the harmless manganese slag was prepared according to the requirements of different element detection methods, and was used for the detection of different components in the manganese slag after the harmless treatment. S was detected by an infrared carbon-sulfur instrument, Cl was detected by ion chromatography, Al2O3, Fe2O3 and CaO were detected by chemical titration, MgO, K2O and Na2O were detected by atomic absorption, and the detection results of the main component contents of the manganese slag sample after the harmless treatment in Example 4 are listed in Table 4.

[0138] Table 1: Mn 2+ and NH4 + leaching concentrations after the leaching experiment of the samples in different embodiments and comparative examples

[0139] Sample name Mn 2+ Leaching concentration (mg / L) NH4 + Leaching concentration (mg / L) Example 1 0.078 1.43 Example 2 0.071 1.26 Example 3 0.065 1.07 Example 4 0.057 0.85 Example 5 0.043 0.73 Example 6 0.036 0.62 Comparative Example 1 1.762 267 Comparative Example 2 1.533 231

[0140] Table 2: Element contents of Zn, As, Pb, Cd, Cu and Cr in the leaching solution of the leaching experiment of the samples in Example 4

[0141] Element Content / (μg / L) Element Content / (μg / L) Zn 98.9 As 2.61 Pb 0.12 Cd 21.6 Cu 1.07 Cr 0.28

[0142] Table 3: Compressive strength and pH of the solidified body of the harmless manganese slag obtained in different embodiments and comparative examples

[0143] Sample name Compressive strength of modified manganese residue solidified body / MPa pH of modified manganese residue solidified body Example 1 5.9 6.2 Example 2 6.8 6.5 Example 3 7.6 6.7 Example 4 8.1 7 Example 5 10.2 7.2 Example 6 12.1 7.5 Comparative Example 1 3.4 5.3 Comparative Example 2 3.8 5.9

[0144] Table 4: Detection results of the main component contents of the manganese slag sample after the harmless treatment in Example 4

[0145] Ingredient Content / % Ingredient Content / % Al2O3 529 CaO 10.7 Fe2O3 11.77 S 8.13 Cl 0.013 MgO 1.96 K2O 1.4 Na2O 0.16

[0146] The process flow of the manganese slag solidification and stabilization treatment method is as follows Figure 1As shown, according to the experimental examples, the harmless manganese slag solidified body prepared in each example and comparative example was subjected to leaching experiment, and the results are shown in Table 1 and Figure 2 As shown, the leaching concentration of Mn 2+ and NH4 + was determined, and it can be seen that the solidification effect of Mn 2+ and NH4 + is significant with the use of manganese solidification agent and ammonia-nitrogen solidification agent. With the decrease of the amount of manganese solidification agent, the leaching concentration of Mn 2+ increases, and the solidification effect decreases. With the increase of the amount of ammonia-nitrogen solidification agent, the leaching concentration of NH4 + decreases, and the solidification effect increases. It is not difficult to find the correlation between the compressive strength and pH of the harmless manganese slag solidified body and the solidification process of the manganese slag through the determination of the compressive strength and pH of the harmless manganese slag solidified body, as shown in Table 1 and Figure 3-4 As shown, with the more complete solidification, the compressive strength of the solidified body is improved. Since the solidification of manganese slag needs to provide an alkaline environment, the pH of the leaching solution also changes. Secondly, the effect of the addition of graphene nanosheet in the manganese solidification agent on the solidification of manganese slag was explored. The addition of graphene nanosheet significantly improves the solidification effect of Mn 2+ . This is because graphene nanosheet helps to promote the formation of C-(A)-S-H gel, making the structure of the solidified body more compact and better covering Mn 2+ . Benefiting from the good mechanical strength of graphene nanosheet, the compressive strength of the harmless manganese slag solidified body is improved. Finally, the solidification stability effect of high-silicon aluminum solid waste on manganese slag was explored. Taking coal gangue as an example, coal gangue is combined with CaO, and the hydration of Al2O3 and SiO2 in coal gangue forms a special structure of gel material. The specific surface area of CaO hydration product is large, and it has good adsorption and wrapping effect on Mn 2+ . However, if coal gangue is not added as an auxiliary, only CaO is used, the compressive strength of the solidified body is significantly reduced. The test results in Table 1, Table 2 and Table 4 also show that the solidification stability effect of the technical solution on manganese slag is obvious.

[0147] The above describes the present application and its embodiments, the described embodiments are part of the embodiments of the present application, but not all the embodiments, and the embodiments shown in the drawings are only one of the many embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application, based on which, other specific embodiments of the present application obtained by the skilled in the art without creative labor should fall within the scope of protection of the present application.

Claims

1. A method for harmlessly treating manganese slag, comprising the following processes: filter press manganese slag, manganese slag pretreatment, and solidification treatment; The pretreatment of manganese slag is achieved by adding manganese curing agent, ammonia nitrogen curing agent, and alkali activator to the manganese slag. The mass fractions of manganese slag, manganese curing agent, ammonia nitrogen curing agent, and alkali activator are as follows: manganese slag 89%~94.9%, manganese curing agent 4%~6.5%, ammonia nitrogen curing agent 1%~3.5%, and alkali activator 0.1%~1%. The manganese curing agent is composed of the following components in parts by weight: The mixture consists of 10-15 parts high-silicon aluminum solid waste, 0.5-5 parts graphene nanosheets, and 2-5 parts CaO. The high-silicon aluminum solid waste is either coal gangue or aluminum ash. The CaO is an analytical grade reagent with a purity of 98 wt%. The graphene nanosheets have a diameter of 5-10 μm, a thickness of 3-10 nm, and a specific surface area of ​​30-31 m². 2 / g; The ammonia nitrogen curing agent is anhydrous phosphogypsum with a particle size of 10~50μm, and the amount added is 6~14 parts by weight. The alkaline activator is composed of raw materials in the following molar ratio: NaOH:KOH = 1:

1. Both NaOH and KOH are granular analytical grade reagents with a purity of 96%.

2. The method for harmlessly treating manganese slag according to claim 1, characterized in that, The preparation of the manganese curing agent includes the following steps: Q1. Add the dispersant to 1L of deionized water at a rate of 0.5g / L, stir to dissolve, stir at a speed of 100~300rpm for 10~20min, add graphene nanosheets and ultrasonically disperse for 15~25min until the graphene nanosheets are evenly dispersed to obtain a graphene nanosheet dispersion. Q2, grind the high-silicon aluminum solid waste and pass it through a 200-mesh sieve for later use to obtain high-silicon aluminum solid waste powder; Q3. Take the graphene nanosheet dispersion obtained in step Q1, the high-silicon aluminum solid waste powder obtained in step Q2, and CaO according to the formula ratio. The three parts together form a manganese solidifying agent, which is mixed with manganese slag when used.

3. The method for harmless treatment of manganese slag according to claim 2, characterized in that, The dispersant mentioned in step Q1 is polyvinylpyrrolidone, with an average molecular weight of 58,000 and a density of 1.14 g / cm³. 3 .

4. The method for harmlessly treating manganese slag according to claim 3, characterized in that, The preparation method of the ammonia nitrogen curing agent is as follows: take anhydrous phosphogypsum according to the formula ratio, grind it and pass it through a 200-mesh sieve for later use, and obtain anhydrous phosphogypsum powder, which is the ammonia nitrogen curing agent.

5. The method for harmlessly treating manganese slag according to claim 4, characterized in that, The alkaline activator is prepared by dissolving KOH and NaOH together in deionized water according to a certain ratio.

6. The method for harmlessly treating manganese slag according to claim 5, characterized in that, The filter press manganese residue includes the following steps: P1. Stir and mix the manganese slag to ensure that the particles are evenly distributed. Then, load it into a filter press and pressurize the filter press at a pressure of 2-3 MPa for 1-2 hours. After the filter press is completed, the filtrate and solid particles retained on the filter medium are obtained. P2, collect the filtrate and the solid particles retained on the filter medium obtained in step P1 respectively. The solid particles retained on the filter medium are the manganese residue from the filter press.

7. The method for harmlessly treating manganese slag according to claim 6, characterized in that, The manganese slag pretreatment includes the following steps: S1, the manganese slag from the filter press is transferred into a dispersing mixer by a loader, ammonia nitrogen curing agent is added, and the mixture is stirred for 10~30 minutes at a speed of 200~400 rpm to obtain the first stage mixture; S2, add the manganese curing agent to the first stage mixture obtained in step S1 in two steps. First, add the graphene nanosheet dispersion and stir for 10-20 minutes at a stirring speed of 200-400 rpm. Then, add the uniformly sized high-silicon aluminum solid waste and CaO together and stir for 20-30 minutes at a stirring speed of 200-400 rpm to obtain the second stage mixture. S3, add the alkali activator to the second stage mixture obtained in step S2, in three portions according to the total amount, with each portion having a ratio of 5:3:

2. Stir for 10 minutes between the first and second additions at a stirring speed of 200-300 rpm. After the third addition, stir for 1-2 hours at a stirring speed of 200-300 rpm until well mixed to obtain the third stage mixture. S4. After the third-stage mixture obtained in step S3 is transported to the ground by conveyor belt, it is transferred to the storage site to obtain manganese slag to be solidified.

8. The method for harmlessly treating manganese slag according to claim 7, characterized in that, The solidification process is one of underground filling or open-pit backfilling.

9. The method for harmless treatment of manganese slag according to claim 8, characterized in that, The downhole filling operation is as follows: the manganese slag to be solidified is transferred to the mud pool next to the wellhead, water is added to the pool and the manganese slag to be solidified is stirred into a thin mud slurry, and the manganese slag to be solidified is transported to the well using a mud pump through a pipeline. After 28 days, it is completely solidified to obtain a harmless solidified manganese slag body.

10. A method for harmlessly treating manganese slag according to claim 9, characterized in that, The open-air backfilling operation is as follows: the manganese slag to be solidified is transported to the backfilling site, mechanically compacted, and then completely solidified after 28 days to obtain a harmless solidified manganese slag body.

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