阅读说明：本技术 一种有色金属尾矿中危重金属砷和铅原位分离富集方法 (in-situ separation and enrichment method for critical metal arsenic and lead in non-ferrous metal tailings ) 是由 唐富顺 黄太铭 杨宏斌 黄雪约 张鹏举 李晓辉 张慧文 韦夏夏 于 2019-08-10 设计创作，主要内容包括：本发明公开了一种有色金属尾矿中危重金属砷和铅原位分离富集方法。有色金属尾矿经酸浸后,以高温碱熔活化,以活化矿料作为合成ZSM-5分子筛所需要硅源、铝源和碱源,以醇类为主要结构导向剂,利用水热法进行ZSM-5分子筛的合成。将合成产物ZSM-5分子筛吸附尾矿酸浸液和合成余液中的重金属离子,达到原位富集部分As和Pb危重金属的效果。本发明以有色金属尾矿为原料,合成ZSM-5分子筛时以乙醇或正丁醇为导向剂而无需添加有机胺模板剂,所得ZSM-5产物对尾矿酸浸液中As和Pb离子具有较好的吸附效果,能达到原位富集尾矿中的As和Pb危重金属,具有“以废治废”、工艺绿色化、无害化和减量化处置有色金属尾矿的特征。(The invention discloses an in-situ separation and enrichment method for critical metals arsenic and lead in non-ferrous metal tailings. The method comprises the steps of carrying out acid leaching on non-ferrous metal tailings, carrying out high-temperature alkali fusion activation, taking activated mineral aggregate as a silicon source, an aluminum source and an alkali source required by synthesis of the ZSM-5 molecular sieve, taking alcohols as a main structure directing agent, and carrying out synthesis of the ZSM-5 molecular sieve by using a hydrothermal method. The synthesized product ZSM-5 molecular sieve adsorbs heavy metal ions in tailing acid leaching solution and synthesized residual liquid, thereby achieving the effect of enriching partial As and Pb critical metals in situ. The method takes the nonferrous metal tailings As a raw material, ethanol or n-butanol is taken As a guiding agent during synthesis of the ZSM-5 molecular sieve, and no organic amine template agent is added, so that the obtained ZSM-5 product has a good adsorption effect on As and Pb ions in the tailing acid leaching solution, can achieve in-situ enrichment of As and Pb critical metals in the tailings, and has the characteristics of 'treatment of waste by waste', green, harmless and quantitative treatment of the nonferrous metal tailings.)

1. An in-situ separation and enrichment method of critical metal arsenic and lead in non-ferrous metal tailings is characterized by comprising the following specific steps:

(1) grinding the nonferrous metal tailings to obtain an original ground mineral aggregate with the grain size of less than 100 meshes, and drying in an oven at the temperature of 100 ~ 200 ℃ in the air atmosphere until the weight loss rate is less than 5% to obtain a dried mineral aggregate;

(2) placing the dried ore material obtained in the step (1) and a dilute nitric acid solution with the mass percentage concentration of 3 ~ 20% in a container according to the proportion of 1g:3 ~ 40mL, stirring at the temperature of 45 ~ 90 ℃ for 1 ~ 8 hours, then carrying out solid ~ liquid separation treatment, collecting acid washing liquor for later use, washing the obtained solid slag until the pH value of the filtrate is reduced to be neutral, collecting the obtained solid, and drying the solid in an air atmosphere at the temperature of 100 ~ 200 ℃ for 2 ~ 12 hours to obtain a dried acid leaching ore material;

(3) calcining the dried acid leaching mineral aggregate obtained in the step (2) and solid NaOH in a muffle furnace at the mass ratio of 1:0.8 ~ 2.0 in the air atmosphere at 500 ~ 800 ℃ for 1 ~ 5 hours, namely, carrying out high ~ temperature alkali fusion activation to obtain a high ~ temperature activated mineral aggregate;

(4) stirring and hydrolyzing the high ~ temperature activated mineral aggregate obtained in the step (3) and distilled water according to the proportion of 1g:4 ~ 8mL, and then carrying out centrifugal impurity removal treatment for 10 ~ 20 minutes at the rotating speed of 1500 ~ 3000 r/min to obtain an upper ~ layer impurity ~ removed activated mineral aggregate solution;

(5) transferring the solution of the impurity ~ removed activated mineral aggregate obtained in the step (4) into a reaction vessel, stirring for 0.5 ~ 2 hours at the constant temperature of 40 ~ 60 ℃, taking organic alcohol as a structure guiding agent, adding seed crystal and distilled water into the synthetic liquid, and leaching SiO in the mineral aggregate by dried acid₂Amount of (i) SiO_{2 feeding}For reference, the use amounts of the organic alcohol, the seed crystal and the distilled water are calculated, and the proportions are respectively organic alcohol/SiO_{2 feeding}a molar ratio =0.1 ~ 4, seed/SiO_{2 feeding}the mass ratio =0.002 ~ 0.02 and H₂O/SiO_{2 feeding}sequentially adding the required organic alcohol and the required seed crystal, washing the seed crystal adhered to the bottle mouth cleaned by the required distilled water into the synthetic solution, and stirring for 15 minutes;

The organic alcohol is absolute ethyl alcohol or chemically pure butanol;

the seed crystal is ZSM-5 molecular sieve and SiO thereof₂/Al₂O₃The molar ratio is more than 20;

(6) dropwise adding 65% by mass of concentrated nitric acid into the product obtained in the step (5), adjusting the pH to 10.6 ~ 11.2, stirring for 1 hour, and then standing and aging for 0 ~ 24 hours at a constant temperature of 40 ~ 60 ℃ to obtain a mixed suspension before crystallization;

(7) transferring the mixed suspension obtained in the step (8) before crystallization into a reaction kettle for hydrothermal crystallization reaction at the temperature of 150 ~ 220 ℃ for 3 ~ 30 hours, filtering after the reaction is finished, carrying out solid ~ liquid separation treatment, collecting the synthetic residual liquid for later use, washing filter residues by distilled water until the pH of the filtrate is neutral, and drying the obtained filter cake in an oven at the temperature of 100 ~ 200 ℃ to obtain a Na ~ ZSM ~ 5 product containing organic alcohol in a pore channel;

(8) heating the Na ~ ZSM ~ 5 product containing the organic alcohol in the pore channel obtained in the step (7) to 500 ~ 600 ℃ at a heating rate of 5 ~ 10 ℃/min in a muffle furnace, and calcining for 4 hours to obtain a Na ~ ZSM ~ 5 product with the organic alcohol removed in the pore channel;

(9) carrying out ion exchange on the Na ~ ZSM ~ 5 product with the organic alcohol removed in the pore passage obtained in the step (8) and an ammonium nitrate solution with the concentration of 0.5 ~ 2.0mol/L for 1 ~ 10 hours at the temperature of 40 ~ 80 ℃ according to the proportion of 1g: 10 ~ 40mL, then carrying out filtration and washing treatment, and drying at the temperature of 100 ~ 200 ℃ to obtain dried NH₃-a ZSM-5 molecular sieve product;

(10) Drying NH obtained in the step (9)₃the ZSM ~ 5 product is heated to 500 ~ 600 ℃ at a heating rate of 5 ~ 10 ℃/min in a muffle furnace and is calcined for 4 hours to obtain an H ~ ZSM ~ 5 product;

(11) respectively dropwise adding ammonia water with the concentration of 0.5 ~ 5mol/L into the pickling solution collected in the step (2) and the synthesis residual solution collected in the step (7) to adjust the pH value to 4.0 ~ 6.0, then adding the H ~ ZSM ~ 5 product obtained in the step (10), adsorbing heavy metal ions for 1 ~ 10 hours under the constant ~ temperature shaking condition at the temperature of 30 ~ 60 ℃, and analyzing the concentrations of the heavy metal ions in the pickling solution and the synthesis residual solution, namely the adsorbed solution before adsorption and the adsorbed solution after shaking;

(12) Carrying out H-type regeneration treatment on the ZSM-5 adsorbing the heavy metal ions in the step (11) according to the step (9) and the step (10), and repeatedly using the ZSM-5 for adsorbing the heavy metal ions or using the ZSM-5 as a product for other applications; and collecting and storing heavy metal-containing solution obtained after ion exchange of ammonium nitrate solution to obtain solution enriched with heavy metal for further concentration treatment.

Technical Field

The invention discloses an in-situ separation and enrichment method of critical metal arsenic and lead in non-ferrous metal tailings, and relates to harmless treatment of non-ferrous metal tailings containing critical metal As and Pb. The process can realize in-situ enrichment of the critical metals As and Pb in the tailings, and simultaneously prepare the ZSM-5 product.

Background

Guangxi plain has the reputation of "the country of non-ferrous metals", but in recent years, the increase of mining strength of various metal mines causes the generation of a large amount of non-ferrous metal tailings, which has important influence on local environment, soil, water resources and the like. For most nonferrous metal tailings, besides a large amount of silicon-aluminum components, the tailings also contain a certain trace amount of critical metal elements such As As and Pb. This is also the reason why the current handling of nonferrous metal tailings in Guangxi cannot be used for road beds, building materials and the like, but the mode of piling up a large amount of tailings can cause heavy metal pollution of land due to acid rain erosion and long-term storage. Therefore, how to realize the harmless and resource cooperative treatment of the nonferrous metal tailings containing the critical metals becomes an urgent need for major environmental and social problems in the nonferrous metal mining industry in Guangxi and even China.

The ZSM-5 molecular sieve has a unique microporous structure and a higher specific surface area, and H-typed H-ZSM-5 has exchange adsorption capacity to metal ions. The non-ferrous metal tailings contain a large amount of silicon-aluminum components and can be used as a raw material for synthesizing ZSM-5. If the non-ferrous metal tailings are used As raw materials, a ZSM-5 molecular sieve is synthesized, and then the synthesized product ZSM-5 molecular sieve is used for adsorbing the critical metals As and Pb in the tailings, so that the critical metals As and Pb in the tailings can be enriched in situ, the ZSM-5 product can be prepared, the green harmless treatment of 'treating waste with waste' is realized, and the effective utilization of the tailings in reduction is realized. Certainly, in the industrial synthesis of the ZSM-5 molecular sieve, organic amine is required to be added as a template agent, and a large amount of organic amine escapes when the organic template agent in a pore channel of a synthetic product is removed, so that the pollution to the production environment and the atmosphere is caused to a certain degree. Therefore, a green synthesis process is developed, and the critical metals As and Pb in the tailings are enriched in situ, so that the method has important significance for treating and reducing the heavy metal pollution of the mine environment.

Disclosure of Invention

Aiming at the risk of environmental hazard caused by heavy metal pollution of the current nonferrous metal tailings and the realization of harmless and green resource cooperative treatment of the nonferrous metal tailings containing the critical metal, the invention aims to provide a method for synthesizing a ZSM-5 molecular sieve by taking the nonferrous metal tailings As a raw material and adopting a green synthesis process, and in-situ enriching the obtained product on the critical metal As and Pb in the tailings. The method takes the nonferrous metal tailings As a raw material, takes ethanol or n-butanol As a guiding agent without adding an organic amine template agent when synthesizing the ZSM-5 molecular sieve, enriches critical metals As and Pb in the tailings in situ, and has the characteristics of treating wastes with processes of' treating wastes with processes of greenness, harmlessness and reduction treatment of the nonferrous metal tailings.

The method comprises the following specific steps:

(1) Grinding the nonferrous metal tailings to obtain an original ground mineral aggregate with the grain size of less than 100 meshes, and drying in an oven at the temperature of 100-200 ℃ in the air atmosphere until the weight loss rate is less than 5% to obtain a dried mineral aggregate.

(2) Mixing the dried ore material obtained in the step (1) with a dilute nitric acid solution with the mass percentage concentration of 3% -20% according to the weight ratio of 1g: 3-40 mL of pickling solution is placed in a container, stirred for 1-8 hours at the temperature of 45-90 ℃, then subjected to solid-liquid separation, and collected for later use; and (3) washing the obtained solid slag until the pH value of the filtrate is reduced to be neutral, collecting the obtained solid, and drying the solid in an air atmosphere at the temperature of 100-200 ℃ for 2-12 hours to obtain the dried acid leaching mineral aggregate.

(3) And (3) calcining the dried acid leaching mineral aggregate obtained in the step (2) and solid NaOH in a muffle furnace at the temperature of 500-800 ℃ for 1-5 hours in the air atmosphere according to the mass ratio of 1: 0.8-2.0 (namely, high-temperature alkali fusion activation), so as to obtain a high-temperature activated mineral aggregate.

(4) And (3) stirring and hydrolyzing the high-temperature activated mineral aggregate obtained in the step (3) and distilled water according to the proportion of 1g: 4-8 mL, and then carrying out centrifugal impurity removal treatment for 10-20 minutes at the rotating speed of 1500-3000 revolutions per minute (rpm) to obtain an upper impurity removal activated mineral aggregate solution.

(5) And (4) transferring the impurity-removed activated mineral aggregate solution obtained in the step (4) to a reaction container, and stirring for 0.5-2 hours at a constant temperature of 40-60 ℃. Organic alcohol is used as a structure directing agent, and crystal seeds and distilled water are added into the synthetic liquid, wherein the dried acid is used for leaching SiO in the mineral aggregate₂Amount of (i.e. SiO)_{2 feeding}) For reference, the use amounts of the organic alcohol, the seed crystal and the distilled water are calculated, and the proportions are respectively organic alcohol/SiO_{2 feeding}0.1 to 4 molar ratio seed crystal/SiO_{2 feeding}the mass ratio of (0.002-0.02) to (H)₂O/SiO_{2 feeding}The mass ratio is 5-50. Adding the required organic alcohol and the crystal seeds in sequence, washing the crystal seeds adhered to the bottle mouth of the required distilled water into the synthetic solution, and stirring for 15 minutes.

The organic alcohol is absolute ethyl alcohol or chemically pure butanol;

The seed crystal is ZSM-5 molecular sieve and SiO thereof₂/Al₂O₃The molar ratio is more than 20.

(6) Dropwise adding 65 mass percent concentrated nitric acid into the product obtained in the step (5), adjusting the pH value to 10.6-11.2, stirring for 1 hour, and then standing and aging for 0-24 hours at a constant temperature of 40-60 ℃ to obtain a mixed suspension before crystallization.

(7) Transferring the mixed suspension obtained in the step (8) before crystallization to a reaction kettle for hydrothermal crystallization reaction at the temperature of 150-220 ℃ for 3-30 hours; filtering after the reaction is finished, carrying out solid-liquid separation treatment, and collecting the synthetic residual liquid for later use; washing the filter residue with distilled water until the pH of the filtrate is neutral, and drying the obtained filter cake in an oven at the temperature of 100-200 ℃ to obtain the Na-ZSM-5 product with the organic alcohol in the pore channel.

(8) And (4) heating the Na-ZSM-5 product containing the organic alcohol in the pore channel obtained in the step (7) to 500-600 ℃ at the heating rate of 5-10 ℃/min in a muffle furnace, and calcining for 4 hours to obtain the Na-ZSM-5 product with the organic alcohol removed in the pore channel.

(9) And (3) mixing the Na-ZSM-5 product with the organic alcohol removed in the pore channel obtained in the step (8) and an ammonium nitrate solution with the concentration of 0.5-2.0 mol/L according to the weight ratio of 1g: 10-40 mL, performing ion exchange at 40-80 ℃ for 1-10 hours, then performing filtration and water washing treatment, and drying at 100-200 ℃ to obtain dried NH₃-a ZSM-5 molecular sieve product.

(10) Drying NH obtained in the step (9)₃and (3) heating the-ZSM-5 product to 500-600 ℃ at a heating rate of 5-10 ℃/min in a muffle furnace, and calcining for 4 hours to obtain the H-ZSM-5 product.

(11) And (3) respectively dropwise adding ammonia water with the concentration of 0.5-5 mol/L into the pickling solution collected in the step (2) and the synthesis residual solution collected in the step (7) to adjust the pH value to 4.0-6.0, adding the H-ZSM-5 product obtained in the step (10), adsorbing heavy metal ions for 1-10 hours under the constant-temperature shaking condition at the temperature of 30-60 ℃, and analyzing the concentrations of the heavy metal ions in the pickling solution, the synthesis residual solution (before adsorption) and the adsorbed solution (after adsorption) after shaking. The feeding ratio of the H-ZSM-5 and the pickling solution or the synthesis residual liquid is not limited, and can be determined according to the heavy metal adsorption capacity of the H-ZSM-5 product.

(12) And (3) carrying out H-type regeneration treatment on the ZSM-5 adsorbing the heavy metal ions in the step (11) according to the step (9) and the step (10), and repeatedly using the ZSM-5 for adsorbing the heavy metals or using the ZSM-5 as a product for other applications. And collecting and storing heavy metal-containing solution obtained after ion exchange of ammonium nitrate solution to obtain solution enriched with heavy metal for further concentration treatment.

In the method for synthesizing ZSM-5 by using ethanol as a main structure directing agent in a hydrothermal mode, if the ethanol is used as a template agent alone, a ZSM-5 molecular sieve product with low relative crystallinity can be obtained, but when the crystallization time is prolonged continuously, obvious mordenite heterocrystal diffraction peaks appear in the obtained product along with the gradual rise of the pH value of a synthetic liquid. Therefore, in order to ensure the purity of the product, a small amount of ZSM-5 seed crystals are added into the synthesis system, so that the occurrence of mordenite mixed crystals can be effectively inhibited, and the purity of the obtained ZSM-5 molecular sieve product is ensured. The method overcomes the defect that a high-content organic amine template agent is used in the traditional synthetic process of synthesizing the ZSM-5 molecular sieve with high crystallinity, and simultaneously, the obtained product is applied to the adsorption of critical metal ions in the tailings, thereby effectively realizing the comprehensive treatment of the green cyclic process of 'treating waste by waste' of the nonferrous metal tailings.

Drawings

FIG. 1 is an XRD diffraction pattern of H-ZSM-5 prepared in example 1 of the present invention.

FIG. 2 is an SEM picture of H-ZSM-5 prepared in example 1 of the present invention.

Detailed Description

The present invention will be described in detail below with reference to specific examples, but it should be understood that the present invention is not limited to the examples.