Method for separating fluorine and lead in high-fluorine lead-containing mercury slag

Abstract

The invention discloses a method for separating fluorine and lead in high-fluorine lead-containing mercury slag, which comprises the following steps: S1, complexing leaching: placing the high-fluorine lead-containing mercury slag in a chlorinated aqueous solution to obtain a mixture, carrying out acid regulation treatment, then carrying out complexing leaching, and carrying out solid-liquid separation to obtain fluorine-containing lead liquid and defluorinated lead slag; s2, cooling crystallization: carrying out cooling crystallization on the fluorine-containing lead liquid obtained in S1, and carrying out solid-liquid separation to obtain lead chloride and a fluorine-containing liquid; s3, precipitation: adding sodium fluoride into the fluorine-containing solution obtained in S2 to obtain a mixed solution, and sequentially performing precipitation and solid-liquid separation on the mixed solution to obtain cryolite and a post-precipitation solution; and the precipitated liquid is reused in the complexing leaching process in the step S1. Compared with the prior art, the method for separating fluorine and lead in the high-fluorine lead-containing mercury slag is simple in process, efficient separation and recovery of lead fluoride in the high-fluorine lead-containing mercury slag are achieved, effective utilization of resources is achieved, and high economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of resource utilization of nonferrous metal smelting waste, and in particular to a method for separating fluorine and lead in high-fluorine lead-containing mercury slag. Background Art

[0002] With the development of the economy and the acceleration of urbanization, the demand for non-ferrous metals such as lead, zinc, and copper in traditional fields such as electricity, construction, and transportation continues to grow. Emerging fields such as new energy, electric vehicles, and power storage batteries will also become new growth points for non-ferrous metal consumption. However, during the high-temperature smelting process of lead and zinc ores, most of the volatile elements in the minerals, such as fluorine, lead, selenium, and mercury, enter the flue gas. Before entering the sulfuric acid workshop, these fluorine- and lead-containing flue gases are usually captured in the power wave scrubber of the purification process, and after solid-liquid separation, high-fluorine lead-containing mercury slag is formed. According to the Law on the Prevention and Control of Environmental Pollution by Solid Wastes, this high-fluorine lead-containing mercury slag is a hazardous waste. As the output of high-fluorine lead-containing mercury slag increases, its storage becomes more difficult, posing a threat to the surrounding ecological environment, and improper treatment will also cause serious waste of resources.

[0003] The main chemical structures in high-fluorine lead-mercury slag include lead sulfate, calcium fluoride and mercury selenide. Currently, there are many studies on the recovery of selenium and mercury resources in high-fluorine lead-mercury slag. However, lead is easily involved in the crystallization process of fluoride, forming a complex endowment characteristic in which fluorine and lead are highly combined and difficult to separate, making it difficult to separate and reuse fluorine and lead in a cascade. Therefore, the separation of fluorine and lead elements in high-fluorine lead-mercury slag has always been a technical difficulty.

[0004] Therefore, how to provide a method for separating fluorine and lead in high-fluorine lead-containing mercury slag so that it can achieve the technical effect of efficient separation of fluorine and lead is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the problem in the prior art that it is difficult to separate and reuse fluorine and lead elements in high-fluorine lead-containing mercury slag, the technical problem to be solved by the present invention is to provide a method for separating fluorine and lead in high-fluorine lead-containing mercury slag, so that it can achieve the technical effect of achieving efficient separation of fluorine and lead.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for separating fluorine and lead in high-fluorine lead-containing mercury slag, and the method for separating fluorine and lead in high-fluorine lead-containing mercury slag comprises: S1, complex leaching: placing the high-fluorine lead-containing mercury slag in a chlorinated aqueous solution to obtain a mixture, subjecting it to acid adjustment treatment, and then subjecting it to complex leaching, and then subjecting it to solid-liquid separation to obtain a fluorine-containing lead liquid and a defluorinated lead slag; S2, cooling crystallization: subjecting the fluorine-containing lead liquid obtained in S1 to cooling crystallization, and subjecting it to solid-liquid separation to obtain lead chloride and a fluorine-containing liquid; S3, precipitation: adding sodium fluoride to the fluorine-containing liquid obtained in S2 to obtain a mixed solution, and subjecting the mixed solution to precipitation and solid-liquid separation in sequence to obtain cryolite and a post-precipitation liquid; the post-precipitation liquid is reused in the complex leaching process of S1.

[0007] In the first aspect, in S1, the chlorinated aqueous solution includes aluminum chloride and other chlorinating agents; the liquid-to-solid ratio of the chlorinated aqueous solution to the high-fluorine-containing lead-mercury slag is 5 to 20 mL / g.

[0008] In the first aspect, the ratio of the amount of aluminum chloride to the amount of fluorine in the high-fluorine lead-containing mercury slag is 1:6 to 1:1; the other chlorinating agent is preferably ammonium chloride, and the concentration of ammonium chloride is 100 to 200 g / L.

[0009] In the first aspect, the reaction temperature of the complex leaching is 50 to 100° C., and the reaction time of the complex leaching is 0.5 to 2 hours.

[0010] In the first aspect, in S1, the acid adjustment treatment is to use hydrochloric acid to adjust the acidity of the mixture, and the acidity is 1 to 4 mol / L.

[0011] In the first aspect, in S1, the temperature of the solid-liquid separation is 60 to 90°C.

[0012] In the first aspect, in S2, the crystallization temperature of the cooling crystallization is 10 to 40° C., and the crystallization time of the cooling crystallization is 1 to 12 hours.

[0013] In the first aspect, in S3, the molar ratio of fluorine to aluminum dissolved in the mixed solution is 6-7.

[0014] In the first aspect, in S3, the precipitation temperature is 10 to 40° C., and the precipitation time is 0.5 to 3 hours.

[0015] In the first aspect, the precipitation temperature is preferably 20 to 30° C., and the precipitation time is preferably 1 to 1.5 hours.

[0016] Beneficial effects:

[0017] The invention discloses a method for separating fluorine and lead in high-fluorine lead-containing mercury slag. The method comprises the following steps: placing the high-fluorine lead-containing mercury slag in a chlorinated aqueous solution and adjusting the acidity to facilitate the dissociation of calcium fluoride in the high-fluorine lead-containing mercury slag and the formation of a fluorine-aluminum complex. The chlorinated aqueous solution contains aluminum chloride, which reacts with the calcium fluoride in the high-fluorine lead-containing mercury slag to dissociate calcium ions, chloride ions and hexafluoroaluminate ions. The chlorinated aqueous solution also contains other chlorinating agents, which can provide enough chloride ions, so that lead sulfate in the high-fluorine lead-containing mercury slag reacts with chloride ions to generate tetrachlorolead complex ions and sulfate ions, and sulfate ions react with the dissociated calcium ions to generate calcium sulfate. The main reaction involved in the complex leaching process is: 3CaF2+AlCl3→AlF6 3- +3Ca 2+ +3Cl - 、PbSO4+4Cl - →PbCl4 2- +SO4 2- , Ca 2+ +SO4 2- →CaSO4, defluorinated lead slag contains calcium sulfate and selenium, mercury, sulfur and iodine, etc., which can be used in the recovery process of selenium and mercury to recover selenium and mercury, thus realizing resource utilization; fluorinated lead liquid contains hexafluoroaluminate ions and tetrachlorolead complex ions. Since the tetrachlorolead complex is a precipitate at room temperature, the solid-liquid separation temperature is controlled at 60-90°C, which maintains the dissolved state of the tetrachlorolead complex in the solution, so that it is separated from the defluorinated lead liquid, which is conducive to the full leaching of lead in the high-fluorine lead-mercury slag; the cooling method of the fluorinated lead liquid for cooling and crystallization is unlimited, and it can be naturally cooled to the crystallization temperature. The solubility difference of lead chloride in different temperature environments is used to realize the purification and separation of lead, thereby obtaining a high-quality and high-recovery lead chloride product. The main reaction is PbCl4 2- →PbCl2↓+2Cl - After cooling and crystallization, the fluorine-containing liquid contains hexafluoroaluminate ions, which react with the sodium ions in sodium fluoride to produce cryolite. The main reaction is 3Na + +AlF6 3- →Na3AlF6↓, the liquid after precipitation mainly contains fluoride ions, and the liquid after precipitation is reused in the complex leaching process to further recover the fluoride ions; in summary, the method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention is simple in process, convenient in operation, and easy to process, and can remove fluorine and lead in high-fluorine lead-containing mercury slag at one time, thereby realizing efficient separation and recovery of fluorine-complexed lead in high-fluorine lead-containing mercury slag, obtaining lead chloride and cryolite, realizing effective utilization of resources, and having high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only 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.

[0019] Figure 1 The present invention discloses a flow chart of a method for separating fluorine and lead in high-fluorine lead-containing mercury slag.

[0020] Figure 2 It is an XRD test diagram of high-fluorine-containing lead-mercury slag treated in a method for separating fluorine and lead in high-fluorine-containing lead-mercury slag of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0022] Embodiment 1

[0023] like Figure 1 As shown, the present embodiment 1 provides a method for separating fluorine and lead in high-fluorine lead-containing mercury slag, and the method for separating fluorine and lead in high-fluorine lead-containing mercury slag includes: S1, complex leaching: placing the high-fluorine lead-containing mercury slag in a chlorinated aqueous solution to obtain a mixture, acid-adjusting treatment, and then complex leaching, and then solid-liquid separation to obtain fluorine-containing lead liquid and defluorinated lead slag; S2, cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in S1, and obtaining lead chloride and fluorine-containing liquid through solid-liquid separation; S3, precipitation: adding sodium fluoride to the fluorine-containing liquid obtained in S2 to obtain a mixed solution, and the mixed solution is successively subjected to precipitation and solid-liquid separation to obtain cryolite and post-precipitation liquid; the post-precipitation liquid is reused in the complex leaching process of S1.

[0024] The invention discloses a method for separating fluorine and lead in high-fluorine lead-containing mercury slag. The method comprises the following steps: placing the high-fluorine lead-containing mercury slag in a chlorinated aqueous solution and adjusting the acidity to facilitate the dissociation of calcium fluoride in the high-fluorine lead-containing mercury slag and the formation of a fluorine-aluminum complex. The chlorinated aqueous solution contains aluminum chloride, which reacts with the calcium fluoride in the high-fluorine lead-containing mercury slag to dissociate calcium ions, chloride ions and hexafluoroaluminate ions. The chlorinated aqueous solution also contains other chlorinating agents, which can provide enough chloride ions, so that lead sulfate in the high-fluorine lead-containing mercury slag reacts with chloride ions to generate tetrachlorolead complex ions and sulfate ions, and sulfate ions react with the dissociated calcium ions to generate calcium sulfate. The main reaction involved in the complex leaching process is: 3CaF2+AlCl3→AlF63- +3Ca 2+ +3Cl - 、PbSO4+4Cl - →PbCl4 2- +SO4 2- , Ca 2+ +SO4 2- →CaSO4, defluorinated lead slag contains calcium sulfate and selenium, mercury, sulfur and iodine, etc., which can be used in the recovery process of selenium and mercury to recover selenium and mercury, thus realizing resource utilization; fluorinated lead liquid contains hexafluoroaluminate ions and tetrachlorolead complex ions. Since the tetrachlorolead complex is a precipitate at room temperature, the solid-liquid separation temperature is controlled at 60-90°C, which maintains the dissolved state of the tetrachlorolead complex in the solution, so that it is separated from the defluorinated lead liquid, which is conducive to the full leaching of lead in the high-fluorine lead-mercury slag; the cooling method of the fluorinated lead liquid for cooling and crystallization is unlimited, and it can be naturally cooled to the crystallization temperature. The solubility difference of lead chloride in different temperature environments is used to realize the purification and separation of lead, thereby obtaining a high-quality and high-recovery lead chloride product. The main reaction is PbCl4 2- →PbCl2↓+2Cl - After cooling and crystallization, the fluorine-containing liquid contains hexafluoroaluminate ions, which react with the sodium ions in sodium fluoride to produce cryolite. The main reaction is 3Na + +AlF6 3- →Na3AlF6↓, the liquid after precipitation mainly contains fluoride ions, and the liquid after precipitation is reused in the complex leaching process to further recover the fluoride ions; in summary, the method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention is simple in process, convenient in operation, and easy to process, and can remove fluorine and lead in high-fluorine lead-containing mercury slag at one time, thereby realizing efficient separation and recovery of fluorine-complexed lead in high-fluorine lead-containing mercury slag, obtaining lead chloride and cryolite, realizing effective utilization of resources, and having high economic benefits.

[0025] In some possible implementations, in S1, the chlorinated aqueous solution includes aluminum chloride and other chlorinating agents; the liquid-solid ratio of the chlorinated aqueous solution to the high-fluorine lead-containing mercury slag is 5-20 mL / g; the ratio of the amount of aluminum chloride to the amount of fluorine in the high-fluorine lead-containing mercury slag is 1:6-1:1; the other chlorinating agents are preferably ammonium chloride, and the concentration of ammonium chloride is 100-200 g / L; the reaction temperature of the complex leaching is 50-100°C, and the reaction time of the complex leaching is 0.5-2 hours; in S1, the acid adjustment treatment is to use hydrochloric acid to adjust the acidity of the mixture, and the acidity is 1-4 mol / L; in S1, the temperature of the solid-liquid separation is 60-90°C.

[0026] Specifically, in an environment with an acidity of 1 to 4 mol / L and a temperature of 50 to 100°C, calcium fluoride in high-fluorine lead-mercury slag is dissociated into calcium ions and chloride ions under the action of aluminum chloride, and hexafluoroaluminate ions are obtained. The reaction is 3CaF2+AlCl3→AlF6 3- +3Ca 2+ +3Cl - At the same time, other chlorinating agents, such as ammonium chloride, supplement the chloride ions when the chloride ions provided by aluminum chloride are insufficient, so that the lead sulfate in the high-fluorine lead-containing mercury slag reacts with chloride ions to generate tetrachlorolead complex ions and sulfate ions, and the sulfate ions react with the dissociated calcium ions to generate calcium sulfate. The reactions are PbSO4+4Cl - →PbCl4 2- +SO4 2- , Ca 2+ +SO4 2- →CaSO4, the solid-liquid separation temperature is controlled at 60-90℃, which maintains the dissolved state of tetrachlorolead complex in the solution, separates it from the defluorinated lead liquid, and is beneficial to the full leaching of lead in high-fluorine lead-containing mercury slag.

[0027] In some possible implementations, in S2, the crystallization temperature of the cooling crystallization is 10 to 40° C., and the crystallization time of the cooling crystallization is 1 to 12 hours.

[0028] Specifically, the fluorine-containing lead liquid includes tetrachlorolead complex ions and hexafluoroaluminate ions. The fluorine-containing lead liquid is cooled and crystallized, and the solubility difference of lead chloride in different temperature environments is used to purify and separate lead, thereby obtaining a high-quality, high-recovery lead chloride product. The main reaction is PbCl4 2- →PbCl2↓+2Cl - .

[0029] In some possible implementations, in S3, the ratio of the amount of fluorine and aluminum dissolved in the mixed solution is 6 to 7; in S3, the precipitation temperature is 10 to 40°C, and the precipitation time is 0.5 to 3 hours; the precipitation temperature is preferably 20 to 30°C, and the precipitation time is preferably 1 to 1.5 hours.

[0030] Specifically, the hexafluoroaluminate ions in the fluorine-containing liquid react with the sodium ions in the sodium fluoride to produce cryolite, and the main reaction is 3Na + +AlF6 3- →Na3AlF6↓, the precipitated liquid after solid-liquid separation mainly contains fluoride ions, and the precipitated liquid is reused in the complex leaching process to further recover the fluoride ions.

[0031] In order to further illustrate the technical solution of the present application in detail to support the technical problem to be solved by the present application, the preparation method is described below with specific examples, such as Examples 1 to 7.

[0032] Example 1

[0033] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0034] Complex leaching: 10g of high-fluorine lead-mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 150g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0035] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0036] Precipitation: 7 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0037] Example 2

[0038] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0039] Complex leaching: 10g of high-fluorine lead-containing mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 100g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0040] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0041] Precipitation: 7 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0042] Example 3

[0043] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0044] Complex leaching: 10g of high-fluorine lead-containing mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 200g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0045] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0046] Precipitation: 7 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0047] Example 4

[0048] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0049] Complex leaching: 10g of high-fluorine lead-mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 20g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 200g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0050] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0051] Precipitation: 5 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0052] Example 5

[0053] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0054] Complex leaching: 10g of high-fluorine lead-containing mercury slag is placed in 80mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 200g / L, and the mixture is treated with acid to have an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0055] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0056] Precipitation: 7 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0057] Example 6

[0058] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0059] Complex leaching: 10g of high-fluorine lead-containing mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 200g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0060] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 1 hour, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0061] Precipitation: 7 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0062] Example 7

[0063] A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, specifically comprising the following steps:

[0064] Complex leaching: 10g of high-fluorine lead-containing mercury slag is placed in 120mL of chlorinated aqueous solution to obtain a mixture, wherein the concentration of aluminum chloride in the chlorinated aqueous solution is 40g / L, and the concentration of ammonium chloride in the chlorinated aqueous solution is 200g / L, and the mixture is treated with acid to an acidity of 2mol / L, and then complex leaching is performed, wherein the complex leaching temperature is 90°C, the complex leaching time is 1 hour, the stirring speed of the complex leaching is 500 rpm, and solid-liquid separation is performed at 90°C to obtain fluorinated lead liquid and defluorinated lead slag;

[0065] Cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in the complex leaching process, the cooling crystallization temperature is 25° C., the cooling crystallization time is 12 hours, and lead chloride and fluorine-containing liquid are obtained by solid-liquid separation;

[0066] Precipitation: 3 g of sodium fluoride is added to the fluorine-containing liquid obtained in the cooling crystallization step to obtain a mixed solution, the mixed solution is stirred at 30° C. for 1 hour, and cryolite and precipitated liquid are obtained after solid-liquid separation; the precipitated liquid is reused in the complex leaching step.

[0067] The composition of the high-fluorine lead-mercury slag in the example was characterized. The characterization results are shown in Figure 2 and Table 1.

[0068] Table 1 Mass ratio of main element components in high fluorine-containing lead-mercury slag

[0069] element Ca Pb F Se Hg S I Mass ratio / % 37.99 28.24 11.00 8.33 6.53 4.44 1.05

[0070] The separation and recovery effects of fluorine-containing lead in the high-fluorine lead-containing mercury slag treated by Examples 1 to 7 are compared as follows:

[0071] Table 2 The recovery rate of lead and fluorine in high-fluorine lead-containing mercury slag, and the purity of the obtained lead chloride and cryolite

[0072] Example Lead recovery rate / % Fluorine recovery rate / % Lead chloride purity / % Cryolite purity / % Example 1 98.8 99.1 98.5 99.4 Example 2 90.3 99.0 94.6 99.3 Example 3 99.3 99.1 98.9 99.3 Example 4 99.0 89.2 98.5 98.2 Example 5 84.7 99.1 97.2 99.3 Example 6 89.1 99.1 98.5 99.3 Example 7 99.3 78.2 98.9 98.7

[0073] pass Figure 2It can be seen that the main component structure of the high-fluorine lead-containing mercury slag includes lead sulfate, calcium fluoride and mercuric selenide. The main element components in the high-fluorine lead-containing mercury slag are tested, and the top six in terms of mass percentage are calcium, lead, fluorine, selenium, mercury and sulfur respectively; It can be seen from Table 2 that fluorine and lead are separated by a method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention. It can be seen from Comparative Examples 1 to 5 that in the complex leaching process, the amount of chloride ions added seriously affects the leaching transfer of lead in the high-fluorine lead-containing mercury slag, and insufficient chloride ions will lead to a decrease in the leaching transfer of lead. It can be seen from Comparative Examples 3 and 6 that the longer the cooling crystallization time, the more lead is recovered in the cooling crystallization; It can be seen from Comparative Examples 1, 2, 3, 5 and 6 that the addition of chloride ions The amount of sodium fluoride and the cooling crystallization time have little effect on the recovery rate of fluorine; compared with Examples 3, 4 and 7, it can be seen that during the precipitation process, the amount of sodium fluoride added directly affects the recovery rate of fluorine, and the more sodium fluoride is added, the higher the recovery rate of fluorine in the high-fluorine lead-containing mercury slag; in Examples 1 to 7, the recovery rate of lead can reach 99.3%, and the purity of the obtained lead chloride is 94.6% or above, and is mostly stable at around 98.7%. The recovery rate of fluorine can reach 99.1%, and the purity of the obtained cryolite is 98.2% or above, and is mostly stable at above 99%. It can be seen that the method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention realizes the effective separation and recovery of lead and fluorine in the high-fluorine lead-containing mercury slag, and obtains lead chloride and cryolite products with higher purity.

[0074] In summary, the method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention has the following advantages: 1. The present invention adopts the "complex leaching-cooling crystallization-sodium fluoride precipitation" cascade separation process, respectively targeting the fluorine and lead leaching transfer, lead recovery and fluorine recovery in the high-fluorine lead-containing mercury slag, to obtain high value-added lead chloride and cryolite products, and fully realize the effective utilization of fluorine and lead resources; 2. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag of the present invention has simple process, convenient operation, economy and environmental protection, easy to realize large-scale production, and has good development prospects.

[0075] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for separating fluorine and lead in high-fluorine lead-containing mercury slag, characterized in that: The method for separating fluorine and lead in high-fluorine lead-containing mercury slag comprises: S1, complex leaching: placing high-fluorine lead-mercury slag in a chlorinated aqueous solution to obtain a mixture, subjecting it to acid treatment, and then subjecting it to complex leaching, and then subjecting it to solid-liquid separation to obtain a fluorine-containing lead liquid and a defluorinated lead slag; S2, cooling crystallization: cooling and crystallizing the fluorine-containing lead liquid obtained in S1, and obtaining lead chloride and fluorine-containing liquid by solid-liquid separation; S3, precipitation: sodium fluoride is added to the fluorine-containing liquid obtained in S2 to obtain a mixed solution, and the mixed solution is subjected to precipitation and solid-liquid separation in sequence to obtain cryolite and a post-precipitation liquid; the post-precipitation liquid is recycled to the complex leaching process of S1.

2. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 1, characterized in that: In S1, the chlorinated aqueous solution includes aluminum chloride and other chlorinating agents; the liquid-to-solid ratio of the chlorinated aqueous solution to the high-fluorine-containing lead-mercury slag is 5 to 20 mL / g.

3. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 2, characterized in that: The ratio of the amount of aluminum chloride to the amount of fluorine in the high-fluorine lead-containing mercury slag is 1:6 to 1:1; the other chlorinating agent is preferably ammonium chloride, and the concentration of ammonium chloride is 100 to 200 g / L.

4. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 3, characterized in that: The reaction temperature of the complex leaching is 50-100° C., and the reaction time of the complex leaching is 0.5-2 hours.

5. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 4, characterized in that: In S1, the acid adjustment treatment is to use hydrochloric acid to adjust the acidity of the mixture, and the acidity is 1 to 4 mol / L.

6. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 5, characterized in that: In S1, the temperature of the solid-liquid separation is 60-90°C.

7. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 6, characterized in that: In S2, the crystallization temperature of the cooling crystallization is 10 to 40° C., and the crystallization time of the cooling crystallization is 1 to 12 hours.

8. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 7, characterized in that: In S3, the molar ratio of fluorine to aluminum dissolved in the mixed solution is 6-7.

9. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 8, characterized in that: In S3, the precipitation temperature is 10 to 40° C., and the precipitation time is 0.5 to 3 hours.

10. The method for separating fluorine and lead in high-fluorine lead-containing mercury slag according to claim 9, characterized in that: The precipitation temperature is preferably 20 to 30° C., and the precipitation time is preferably 1 to 1.5 hours.

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