Method for recovering tungsten and ammonia from ammonium tungstate feed liquid sulfuration impurity removal slag

Abstract

The invention relates to the technical field of tungsten recovery, in particular to a method for recovering tungsten and ammonia from ammonium tungstate feed liquid sulfuration impurity removal slag. The method comprises the following steps: (1) adding a stripping tower discharge material liquid into the sulfuration impurity removal slag for size mixing to obtain a size mixing material liquid, the temperature of the stripping tower discharge material liquid is more than 80 DEG C, the alkalinity is 4-5g / l, and the ammonia nitrogen content is less than or equal to 10ppm; (2) adding alkali into the slurry mixing liquid at a preset temperature, and maintaining the alkalinity of the solution within a first range to obtain a solid-liquid mixture; (3) filtering the solid-liquid mixture to obtain primary filtrate and primary filter residues, and performing steam stripping deamination on the primary filtrate; (4) adding an acid solution into the primary filter residue and maintaining the acidity of the solution within a second range to obtain a dissolved solution; and (5) adsorbing the dissolved solution by using anion resin, and analyzing to obtain the tungsten recovery solution. By adopting the method provided by the invention, the tungsten recovery rate can be improved, the process is few, and the consumption of steam and caustic soda flakes is greatly reduced; the amount of slag after acid treatment is small, and secondary slag treatment is reduced; and the cost effect is obviously reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tungsten recovery, and in particular to a method for recovering tungsten and ammonia from sulfurized impurity removal slag of ammonium tungstate liquid. Background Art

[0002] In the tungsten smelting industry, sulfidation and impurity removal of ammonium tungstate liquid is one of the key steps in purifying tungsten. However, the traditional method faces multiple technical challenges during the treatment process. First of all, the method involves multiple filter pressing and washing of the impurity-containing slag. This process not only significantly increases the total volume of the slurry, but also leads to a large amount of filtrate rich in impurities and incompletely recovered resources. These filtrates often contain a high amount of residual alkali, and a large amount of additional neutralizers are required to adjust the pH value, thereby increasing the cost burden of subsequent treatment sections. In addition, in order to remove moisture from the filtrate, multiple heating and evaporation are required. This process is not only energy-intensive, especially the significant increase in steam consumption, but also increases the environmental burden. What is more serious is that the highly alkaline slag after multiple filter pressings is classified as hazardous waste, and its safe treatment and disposal has become a major problem.

[0003] On the other hand, when using resin adsorption technology to recover polytungstate from the filtrate, the high ammonia content in the solution becomes a significant constraint. The high ammonia environment not only reduces the adsorption efficiency of the resin on tungsten, causing the adsorbed tungsten to be reversed, thereby affecting the adsorption capacity and service life of the resin, but also increases the subsequent analytical processing costs. At the same time, during the transportation process of high ammonia solution, it is easy to form salt crystals such as ammonium sulfate in the pipeline. These crystals not only block the pipeline and reduce the effective flow of the adsorption column, but also increase the maintenance difficulty and production cost, posing a serious threat to the stability and efficiency of the entire process. Therefore, improving the existing ammonium tungstate liquid sulfide removal and recovery technology to reduce energy consumption, reduce costs, improve resource recovery rate and environmental friendliness has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a method for recovering tungsten and ammonia from the slag of sulfurization and impurity removal of ammonium tungstate liquid.

[0005] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0006] A method for recovering tungsten and ammonia from sulphurization and impurity removal slag of ammonium tungstate liquid comprises the following steps:

[0007] (1) adding the stripping tower discharge liquid to the sulfide impurity removal slag to prepare a slurry to obtain a slurry prepared by mixing the slurry, wherein the stripping tower discharge liquid has a temperature greater than 80° C., a basicity of 4-5 g / l, and an ammonia nitrogen content of ≤10 ppm;

[0008] (2) adding alkali to the slurry solution at a preset temperature and maintaining the alkalinity of the solution within a first range to obtain a solid-liquid mixture;

[0009] (3) filtering the solid-liquid mixture to obtain a primary filtrate and a primary filtrate residue, and performing steam stripping and deammoniation on the primary filtrate;

[0010] (4) adding acid solution to the primary filtration residue and maintaining the acidity of the solution within the second range to obtain a dissolved solution;

[0011] (5) The dissolved solution is adsorbed and analyzed using an anion resin to obtain a tungsten recovery solution.

[0012] In one embodiment, the tungsten content in the sulfide impurity-removing slag is 0.3%-5%, and the ammonia content is 7%-10%.

[0013] In one embodiment, in step (1), the solid-to-liquid ratio after slurry adjustment is greater than 1:4.

[0014] In one embodiment, in step (2), the alkali is flake alkali, and the amount of alkali added is to maintain the alkalinity of the solution in the range of 10-20 g / l.

[0015] In one embodiment, in step (2), the preset temperature is 75-98°C;

[0016] Preferably, the preset temperature is 80° C., and the reaction time of adding alkali is 1 hour.

[0017] In one embodiment, the step (2) further includes collecting and adsorbing free ammonia generated during the reaction.

[0018] In one embodiment, the step (3) further comprises performing a secondary treatment on the primary filtration residue, wherein the secondary treatment is acid dissolution of the primary filtration residue.

[0019] In one embodiment, in step (4), the acid solution comprises at least one of hydrochloric acid, sulfuric acid, phosphoric acid, and carbonic acid.

[0020] In one embodiment, in step (4), the amount of acid solution added is to maintain the acidity of the solution in the range of 10-20 g / l.

[0021] In one embodiment, in step (3), the discharge liquid of the stripping deamination is added to the slurry adjustment of the next cycle as the discharge liquid of the stripping tower in step (1).

[0022] Based on the above, compared with the prior art, the method for recovering tungsten and ammonia from the sulfidation and impurity removal residue of ammonium tungstate liquid provided by the present invention improves the tungsten recovery rate while greatly reducing the process steps; the steam stripping recovery material is used for slurry adjustment, which has a high temperature and contains residual alkali, and can reduce the consumption of steam and alkali; the slag residue after acid addition is reduced, thereby reducing the secondary treatment of the filter residue; the cost is significantly reduced.

[0023] Other features and beneficial effects of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other beneficial effects of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The positional relationships described in the drawings in the following description are based on the directions in which the components are drawn in the diagrams, unless otherwise specified.

[0025] Figure 1 A flow chart of a method for recovering tungsten and ammonia from sulfidation and impurity removal slag of ammonium tungstate liquid provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and cannot be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in the present invention.

[0027] The embodiment of the present invention provides a method for recovering tungsten and ammonia from sulfidation and impurity removal slag of ammonium tungstate liquid, comprising the following steps:

[0028] Step (1), adding the stripping tower discharge liquid to the sulfide impurity removal slag to prepare a slurry to obtain a slurry prepared by mixing the slurry, wherein the stripping tower discharge liquid has a temperature greater than 80° C., a basicity of 4-5 g / l, and an ammonia nitrogen content of ≤10 ppm;

[0029] The content of tungsten in the sulfiding impurity-removing slag is 0.3%-5%, and the content of ammonia is 7%-10%.

[0030] The present invention combines the subsequent stripping tower deep deamination, and uses the stripping tower discharge liquid directly for slurry adjustment. On the one hand, due to the high temperature of the stripping tower discharge liquid, the subsequent steam or heating consumption can be greatly reduced. On the other hand, the stripping tower discharge liquid has its own alkalinity, which can reduce the amount of caustic soda added in the subsequent steps. In particular, the stripping tower discharge liquid used in the present invention needs to meet the temperature of more than 80°C, preferably 98°C, and the alkalinity is within the range of 4-5g / l;

[0031] In a preferred embodiment, the solid-liquid ratio after slurry adjustment is above 1:4, which is conducive to fully stirring the sulfide impurity removal slag and preventing agglomeration, so as to facilitate better subsequent deammoniation and tungsten removal.

[0032] Step (2), adding alkali to the slurry solution at a preset temperature and maintaining the alkalinity of the solution within a first range to obtain a solid-liquid mixture;

[0033] By adding alkali, preferably caustic soda flakes, to the slurry, under a preset temperature and alkaline environment, especially a strong alkaline environment, ammonia is separated from the sulfide impurity removal slag and enters the solution, or the ammonium ions in the solution are will be converted into free ammonia (NH 3 ), and the sulfide impurity removal slag reacts with alkali to generate alkali salts (such as calcium hydroxide, magnesium hydroxide, etc.). Since the tungsten-containing substances that can react with alkali have reacted completely during the alkali treatment process, the tungsten-containing substances in this step react to become sodium tungstate solution, and the generated free ammonia is absorbed and reacted with dilute sulfuric acid to remove ammonia from the slurry solution. The above process includes the following reaction formula:

[0034] XPO 4 NH 4 +NaOH→XOH↓+XNaPO 4 ↓+NH 3 ·H 2 O;

[0035]

[0036] 2NH 3 +H 2 SO 4 =(NH 4 ) 2 SO 4 ;

[0037] H + +OH - =H 2 O;

[0038] Wherein, X refers to a metal cation;

[0039] The preset temperature is 75-98°C, for example, 80°C, preferably above 80°C, to improve the deamination efficiency and reduce the solid ammonia content in the residual material. The reaction time of adding alkali is adaptively adjusted according to the residual ammonia amount. For example, the preset temperature is 80°C and the alkali adding time is 1h, which can effectively ensure that the deamination and tungsten removal reactions are fully carried out to achieve the expected conversion rate and extraction effect;

[0040] Furthermore, the amount of alkali added is to maintain the alkalinity of the solution within the range of 10-20 g / l, so as to ensure normal deamination and control the consumption of caustic soda flakes, thereby reducing the processing cost;

[0041] Step (3), filtering the solid-liquid mixture to obtain a primary filtrate and a primary filtrate residue, and performing steam stripping and deammoniation on the primary filtrate;

[0042] The primary filter residue mainly contains magnesium ammonium phosphate, calcium hydroxide, magnesium hydroxide, calcium sulfate, magnesium sulfate, calcium tungstate, etc.; the primary filtrate mainly contains sodium tungstate, ammonia water, etc.;

[0043] The step (3) further includes performing a secondary treatment on the primary filter residue, wherein the secondary treatment is acid dissolution of the primary filter residue to further dissolve the tungsten in the primary filter residue, so as to facilitate subsequent enrichment and recovery of tungsten using resin;

[0044] During the steam stripping deamination process, the deamination temperature is controlled within the range of 99-105°C, and the alkalinity of the liquid environment is controlled within the range of 5-10g / l;

[0045] In step (3), the discharge liquid of the stripping deamination can be used as the discharge liquid of the stripping tower in step (1) and can be directly added to the slurry adjustment of the next cycle, thereby realizing the recycling of materials and effectively reducing costs.

[0046] Step (4), adding acid solution to the primary filtration residue and maintaining the acidity of the solution within the second range to obtain a dissolved solution;

[0047] In step (4), acid, especially sulfuric acid, is added to cause sulfate and calcium ions to form a precipitate, which is intercepted by secondary filtration / filter press, thereby reducing the formation of slag in the subsequent resin adsorption process; the tungsten still contained in the slag exists in the form of polytungstate, which is convenient for the enrichment of the resin adsorbent, and other impurities are separated.

[0048] In step (4), the acid solution comprises at least one of hydrochloric acid, sulfuric acid, phosphoric acid and carbonic acid, preferably sulfuric acid.

[0049] In step (4), the amount of the acid solution added is to maintain the acidity of the solution within the range of 10-20 g / l. The control of the acidity is beneficial to the subsequent adsorption of tungsten by the anion resin.

[0050] (5) The dissolved solution is adsorbed and analyzed using an anion resin to obtain a tungsten recovery solution.

[0051] The anion resin is preferably a macroporous anion exchange resin having a high affinity for polytungstate, such as anion 301 resin.

[0052] It should be noted that the inventors have found that when using resin to adsorb tungsten, if the ammonia content in the adsorption solution is too high, the adsorbed tungsten will be decomposed, affecting the adsorption capacity of the resin, thereby greatly increasing the number of analyses required and increasing the analysis cost; therefore, sufficient deammoniation is first performed to greatly reduce the ammonia content in the solution or even approach zero, so as not to affect the adsorption capacity of the resin for tungsten and reduce the analysis cost; not only that, if the ammonia content in the solution is too high, after adding sulfuric acid, ammonium sulfate crystals are easily formed in the pipeline, affecting the flow rate of the adsorption column; therefore, ammonia is removed first to reduce the ammonia content in the solution, which can avoid crystallization in the pipeline; in addition, the inventors found that the prior art uses acid dissolution first, which will result in a high ammonia content in the solution, forming suspended fine slag and a long sedimentation time; while the present invention uses deammoniation first to reduce the ammonia content in the solution, and the slurry is clear, which can be directly adsorbed without sedimentation, greatly shortening the treatment cycle.

[0053] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0054] Examples 1-12

[0055] The same batch of ammonium tungstate liquid was selected for sulfurization and impurity removal. The components were shown in the table below and divided into 12 portions by the same weight. Each portion was added with the stripping tower discharge liquid under the same conditions (discharge temperature ≥ 90°C, alkalinity: 4-5g / l) for slurry boiling. After the reaction time was the same, 12 portions of slurry liquid were obtained.

[0056] Table 1

[0057] Components content(%) Magnesium ammonium phosphate 50 Calcium hydroxide 15 Magnesium hydroxide 15 Magnesium sulfate 8 Calcium sulfate 5 Calcium Tungstate 3 other 4

[0058] Each portion of slurry was subjected to deamination and tungsten removal at different temperatures and alkalinity. The specific reaction data are shown in Table 2 below.

[0059] Table 2

[0060]

[0061] It can be seen from Table 1 that with the increase of temperature, the ammonia content in the solution decreases significantly; with the increase of temperature, the tungsten dissolution rate of the slag also increases; however, considering that when the alkalinity is 10-20g / l, the slag viscosity is low, which is conducive to filtration, the filtration time can be effectively reduced, thereby improving efficiency.

[0062] Examples 13-24

[0063] The same batch of ammonium tungstate liquid as in Example 1-12 was used for sulfurization and impurity removal, and divided into 12 parts by the same weight, and each part was added to the stripping tower discharge liquid under the same conditions (discharge temperature ≥ 90°C, alkalinity: 4-5g / l) for slurry boiling, and reacted for the same time to obtain 12 parts of slurry liquid, and then the 12 parts of slurry liquid were deaminated and tungsten was removed at a temperature of 80°C, the alkalinity of the solution was controlled at 20g / l, and the reaction time was 60min to obtain a solid-liquid mixture;

[0064] The solid-liquid mixture is filtered through a filter press to obtain a primary filtrate and a primary filtrate residue, the primary filtrate is subjected to steam stripping and deammoniation, and each portion of the primary filtrate is subjected to slag decomposition at different temperatures and different acidities. The specific reaction and tungsten dissolution rate data are shown in Table 3 below;

[0065] Table 3 Tungsten dissolution rate of slag after alkali dissolution and acid dissolution

[0066]

[0067] According to Table 2, it can be seen that after acid dissolution, the slag content in the dissolving solution is less, which reduces the treatment of tungsten-containing slag; the temperature has little effect on the slag content (dry slag) after dissolution; the adsorption of polytungstic acid by 301 resin needs to be carried out under acidic conditions, and it is reasonable to control the dissolution acidity to 10-20g / l.

[0068] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0069] Although the terms such as sulfidation impurity removal residue, slurry adjustment, solid-liquid mixture, primary filtrate, primary filtrate residue, stripping deamination, alkalinity, acidity, dissolved liquid, tungsten recovery liquid, etc. are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention; the terms "first", "second", etc. (if any) in the description and claims of the embodiments of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering tungsten and ammonia from the slag removed by sulfurization of ammonium tungstate liquid, characterized in that: The following steps are involved: (1) adding the stripping tower discharge liquid to the sulfide impurity removal slag to prepare a slurry to obtain a slurry prepared by mixing the slurry, wherein the stripping tower discharge liquid has a temperature greater than 80° C., a basicity of 4-5 g / l, and an ammonia nitrogen content of ≤10 ppm; (2) adding alkali to the slurry solution at a preset temperature and maintaining the alkalinity of the solution within a first range to obtain a solid-liquid mixture; (3) filtering the solid-liquid mixture to obtain a primary filtrate and a primary filtrate residue, and performing steam stripping and deammoniation on the primary filtrate; (4) adding acid solution to the primary filtration residue and maintaining the acidity of the solution within the second range to obtain a dissolved solution; (5) The dissolved solution is adsorbed and analyzed using an anion resin to obtain a tungsten recovery solution.

2. The method according to claim 1, characterized in that The content of tungsten and ammonia in the sulfiding impurity-removing slag is 7%-10%.

3. The method according to claim 1, characterized in that In step (1), the solid-liquid ratio after slurry adjustment is above 1:

4.

4. The method according to claim 1, characterized in that In step (2), the alkali is flake alkali, and the amount of the alkali added is to maintain the alkalinity of the solution in the range of 10-20 g / l.

5. The method according to claim 1, characterized in that: In step (2), the preset temperature is 75-98°C.

6. The method according to claim 1, characterized in that The step (2) also includes collecting and adsorbing free ammonia generated during the reaction.

7. The method according to claim 1, characterized in that The step (3) further comprises performing a secondary treatment on the primary filtration residue, wherein the secondary treatment is acid dissolution of the primary filtration residue.

8. The method according to claim 1, characterized in that: In step (4), the acid solution comprises at least one of hydrochloric acid, sulfuric acid, phosphoric acid and carbonic acid.

9. The method according to claim 1, characterized in that: In step (4), the amount of acid solution added is to maintain the acidity of the solution in the range of 10-20 g / l.

10. The method according to claim 1, characterized in that In step (3), the discharge liquid of the stripping and deamination process is added to the slurry preparation of the next cycle as the discharge liquid of the stripping tower in step (1).

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