A method for efficiently enriching germanium by treating vortex furnace dust

Abstract

The present invention discloses a method for efficiently enriching germanium by treating vortex furnace dust. The method comprises the following steps: (1) uniformly mixing vortex furnace dust containing germanium with a vulcanization accelerator to obtain a germanium-containing material; (2) volatilizing the germanium-containing material under a protective atmosphere at a temperature of 1000°C to 1200°C for 2 to 8 hours, collecting dust to obtain germanium-arsenic-rich dust and a volatilized residue; (3) subjecting the germanium-arsenic-rich dust to oxygen pressure leaching treatment, and performing liquid-solid separation to obtain a germanium-rich solution and a leaching residue; (4) adding concentrated hydrochloric acid to the germanium-rich solution to adjust the hydrochloric acid concentration to 8 to 10 mol / L, and distilling to obtain germanium tetrachloride and a distillation residue; (5) diluting the distillation residue to a hydrochloric acid solution concentration of 1 to 2 mol / L, and then returning the distillation residue to the oxygen pressure leaching process. The present invention successfully separates germanium and arsenic from vortex furnace dust by using an oxygen pressure leaching method, and converts arsenic into ferric arsenate. The hydrochloric acid consumption in the subsequent chlorination distillation process is greatly reduced through the above-mentioned pretreatment process, and the arsenic and ferric arsenate are returned to the oxygen pressure leaching arsenic and iron separation process to realize the closed-loop recycling of the chlorination distillation residue.

Description

Technical field:

[0001] The invention relates to the technical field of germanium recovery and extraction, and in particular to a method for efficiently enriching germanium by treating vortex furnace dust. Background technology:

[0002] Germanium is an important strategic metal, widely used in strategic high-tech emerging industries such as aerospace, semiconductors, solar cells, and information communications.

[0003] Germanium, a typical rare metal element, is rarely found as an independent mineral. It often exists as an associated mineral in other minerals and rocks, such as sphalerite, hematite, and lead-zinc ore. A certain amount of germanium is also found in coal, with the highest content found in low-grade lignite. This is primarily found in western Yunnan and the Shengli and Yimin coalfields in Inner Mongolia.

[0004] At present, the main method for extracting germanium from lignite is combustion volatilization, in which germanium is volatilized into smoke in the form of germanium monoxide to obtain smoke containing about 0.5-1 wt.% germanium, which is then extracted by chlorination distillation.

[0005] The devices used in the combustion volatilization process include chain furnaces and vortex furnaces. Compared to chain furnaces, vortex furnaces have higher combustion temperatures (1200°C to 1300°C) and generate more dust. The germanium in the vortex furnace dust is low-grade (less than 1%) and high in silicon. Nearly 30% to 40% of the germanium exists in the form of acid-insoluble germanium (silicon-germanium solid solution and tetragonal germanium dioxide). Subsequent chlorination distillation to extract germanium results in high auxiliary material consumption and low distillation efficiency (germanium recovery rate is less than 60%).

[0006] Because germanium and arsenic have similar properties during lignite combustion, large amounts of arsenic enter the smoke during combustion in a weakly oxidizing atmosphere, often exceeding the germanium content. To prevent arsenic volatilization, the subsequent chlorination distillation process requires the addition of large amounts of oxidants (Cl2, MnO2). This not only results in high consumption of auxiliary materials and reagents, but also increases costs. Furthermore, the distillation residue contains high arsenic content, necessitating additional processing to treat the arsenic-containing wastewater. These issues urgently need to be addressed. Summary of the invention:

[0007] In response to the problems of low germanium content, high proportion of acid-insoluble germanium in existing vortex furnace dust, and difficulty in separating germanium from arsenic, the present invention proposes a method for efficiently enriching germanium in treating vortex furnace dust, in order to overcome the problems of high auxiliary material consumption, low germanium distillation efficiency, and difficult treatment of distillation residue in the existing vortex furnace dust chlorination distillation process.

[0008] The object of the present invention is to provide a method for efficiently enriching germanium by treating vortex furnace dust, comprising the following steps:

[0009] (1) Material preparation: the vortex furnace dust containing germanium and the vulcanization accelerator are mixed uniformly in a mass ratio of 1:0.10 to 0.25 to obtain a germanium-containing material;

[0010] (2) atmosphere-controlled reduction, sulfidation and volatilization: volatilizing the germanium-containing material obtained in step (1) under a protective atmosphere at a temperature of 1000° C. to 1200° C. for 2 to 8 hours, collecting the dust to obtain germanium-arsenic-rich smoke and volatile residue;

[0011] (3) oxygen pressure leaching: subjecting the germanium-arsenic-rich smoke dust obtained in step (2) to oxygen pressure leaching, and obtaining a germanium-rich solution and a leaching residue by liquid-solid separation;

[0012] (4) Chlorination distillation: The germanium-rich solution obtained in step (3) is added with concentrated hydrochloric acid to adjust the hydrochloric acid concentration to 8-10 mol / L, and distilled at a temperature of 110° C. to 120° C. for 0.5-4.0 h to obtain germanium tetrachloride and distillation residue;

[0013] (5) Recycling: The distillation residue is diluted to a hydrochloric acid solution concentration of 1 to 2 mol / L and then returned to the oxygen pressure leaching process to treat the germanium-arsenic-rich smoke with oxygen pressure leaching. The protective atmosphere mentioned in the present invention refers to a nitrogen atmosphere.

[0014] Based on the phase composition characteristics of vortex furnace dust, the present invention first uses calcium sulfate as a sulfurization aid under protective atmosphere conditions to volatilize germanium and arsenic in the vortex furnace dust in the form of germanium sulfide and arsenic sulfide. Subsequently, the germanium-rich dust is leached with oxygen pressure. By controlling the leaching conditions, germanium is converted into soluble H2GeO3 or HGeO3 - Arsenic enters the solution in the form of ferric arsenate, and enters the slag in the form of ferric arsenate, thus achieving harmless disposal of arsenic. Finally, the germanium solution obtained by leaching is subjected to chlorination distillation to obtain germanium tetrachloride product, and the chlorination distillation residue is returned to oxygen pressure leaching.

[0015] Preferably, the vortex furnace dust described in step (1) includes the following components: Ge 0.25-1.50wt.%, C 5-20wt.%, S1-5wt.%, Si 5-25wt.%, As 0.25-5.00wt.%, and Ca 1-10wt.%.

[0016] Preferably, the germanium-containing vortex furnace dust and the vulcanization aid described in step (1) are uniformly mixed in a mass ratio of 1:0.15-0.25 to obtain a germanium-containing material.

[0017] Preferably, the vulcanization aid in step (1) is calcium sulfate.

[0018] Preferably, the germanium-containing material in step (2) is volatilized for 3 to 5 hours in a nitrogen atmosphere at a temperature of 1050° C. to 1200° C., and then dust is collected to obtain germanium-arsenic-rich smoke and volatile residue.

[0019] Preferably, the conditions for the oxygen pressure leaching treatment in step (3) are: the concentration of HCl in the mixed solution of HCl and FeCl2 is 1-2 mol / L, the mass of FeCl2 is 0.05-0.20 times the mass of the germanium-arsenic-rich smoke, the liquid-to-solid ratio of the mixed solution to the germanium-arsenic-rich smoke is 4-7.5 mL / g, the temperature is 80°C-150°C, the oxygen partial pressure is 0.2-0.5 MPa, and the reaction is carried out for 2-5 hours.

[0020] Further preferably, the conditions for the oxygen pressure leaching treatment in step (3) are: the concentration of HCl in the mixed solution of HCl and FeCl2 is 1.2-2.0 mol / L, the mass of FeCl2 is 0.10-0.15 times the mass of the germanium-arsenic-rich smoke, the liquid-solid ratio of the mixed solution to the germanium-arsenic-rich smoke is 4-6 mL / g, the temperature is 100°C-120°C, the oxygen partial pressure is 0.2-0.3 MPa, and the reaction is carried out for 2-4 h.

[0021] Preferably, step (4) specifically comprises the following steps: adding concentrated hydrochloric acid to the germanium-rich solution obtained in step (3) to adjust the hydrochloric acid concentration to 8-9 mol / L, and distilling the mixture at a temperature of 110° C. to 120° C. for 1-2 hours to obtain germanium tetrachloride and a distillation residue.

[0022] Preferably, the distillation residue in step (5) is diluted to a hydrochloric acid solution concentration of 1.2 to 2.0 mol / L and then returned to the oxygen pressure leaching process.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) The present invention successfully achieves the mineral phase transformation of germanium in vortex furnace dust by using a controlled atmosphere reduction volatilization method, converting acid-insoluble germanium (silicon-germanium solid solution and tetragonal GeO2) into soluble germanium sulfide, and the subsequent chlorination distillation efficiency is greatly improved;

[0025] (2) The present invention successfully separated germanium and arsenic from vortex furnace dust by using an oxygen pressure leaching method, and converted arsenic into relatively stable ferric arsenate;

[0026] (3) The present invention greatly reduces the consumption of hydrochloric acid in the subsequent chlorination distillation process through the above-mentioned pretreatment process, and can return to the oxygen pressure leaching arsenic and iron separation process, thereby realizing the closed-loop recycling of the chlorination distillation residue. Description of the drawings:

[0027] Figure 1 The present invention is a process flow chart of a method for efficiently enriching germanium by treating vortex furnace dust. Specific implementation method:

[0028] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0029] In order to make the purpose, technical solutions and advantages of the present invention clearer, the embodiments and implementation schemes of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. The following description of at least one example is actually only illustrative and in no way serves as any limitation on the present invention and its application or use. 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.

[0030] The fuel cell membrane electrode activation method and technical effects of the present invention are described below with reference to specific embodiments.

[0031] The vortex furnace dust described in the following examples is obtained by collecting dust after burning germanium-containing lignite in a vortex furnace, and its main components are Ge 0.75wt.%, C 15wt.%, S 2.5wt.%, Si 20wt.%, As 2.75wt.%, and Ca 6.5wt.%.

[0032] Example 1:

[0033] A method for efficiently enriching germanium by treating vortex furnace dust comprises the following steps:

[0034] (1) Material preparation: Mix vortex furnace dust and calcium sulfate in a mass ratio of 1:0.2 to obtain a germanium-containing material;

[0035] (2) Controlled atmosphere reduction sulfidation volatilization: The obtained germanium-containing material is volatilized in a nitrogen atmosphere at a temperature of 1050°C for 3 hours, and then the dust is collected to obtain germanium-arsenic-rich smoke and volatile residue;

[0036] (3) Oxygen pressure leaching: The obtained germanium-arsenic-rich dust was leached under the conditions of HCl concentration of 1.2 mol / L, liquid-solid ratio of 6 mL / g, temperature of 100°C, oxygen partial pressure of 0.3 MPa, and FeCl2 mass of 0.1 times the mass of the germanium-arsenic-rich dust. After reaction for 3 h, liquid-solid separation was performed to obtain a germanium-rich solution and a leaching residue.

[0037] (4) Chlorination distillation: The chlorination distillation solution was added with concentrated hydrochloric acid to adjust the concentration to 9 mol / L, and distilled at 110°C for 2 hours to obtain germanium tetrachloride and distillation residue;

[0038] (5) Recycling: The distillation residue is diluted to a solution concentration of 1.2 mol / L and then returned to the oxygen pressure leaching process.

[0039] Example 2:

[0040] A method for efficiently enriching germanium by treating vortex furnace dust comprises the following steps:

[0041] (1) Material preparation: Mix vortex furnace dust and calcium sulfate in a mass ratio of 1:0.15 to obtain a germanium-containing material;

[0042] (2) Controlled atmosphere reduction sulfidation volatilization: The germanium-containing material is volatilized in a nitrogen atmosphere at 1100°C for 4 hours, and then the dust is collected to obtain germanium-arsenic-rich smoke and volatile residue;

[0043] (3) Oxygen pressure leaching: The obtained germanium-arsenic-rich dust was leached under the conditions of HCl concentration of 1.5 mol / L, liquid-solid ratio of 5 mL / g, temperature of 110°C, oxygen partial pressure of 0.2 MPa, and FeCl2 mass of 0.15 times the mass of the germanium-arsenic-rich dust. After reaction for 4 h, liquid-solid separation was performed to obtain a germanium-rich solution and a leaching residue.

[0044] (4) Chlorination distillation: The chlorination distillation solution was added with concentrated hydrochloric acid to adjust the concentration to 8 mol / L, and distilled at 115°C for 1.5 hours to obtain germanium tetrachloride and distillation residue;

[0045] (5) Recycling: The distillation residue is diluted to a solution concentration of 1.5 mol / L and then returned to the oxygen pressure leaching process.

[0046] Example 3:

[0047] A method for efficiently enriching germanium by treating vortex furnace dust comprises the following steps:

[0048] (1) Material preparation: Mix vortex furnace dust and calcium sulfate in a mass ratio of 1:0.25 to obtain a germanium-containing material;

[0049] (2) Controlled atmosphere reduction sulfidation volatilization: The germanium-containing material is volatilized in a nitrogen atmosphere at 1200°C for 5 hours, and then the dust is collected to obtain germanium-arsenic-rich smoke and volatile residue;

[0050] (3) Oxygen pressure leaching: The obtained germanium-arsenic-rich smoke is leached under the conditions of HCl concentration of 2 mol / L, liquid-solid ratio of 4 mL / g, temperature of 120°C, oxygen partial pressure of 0.3 MPa, and FeCl2 mass of 0.1 times that of the germanium-arsenic-rich smoke. After reaction for 2 h, liquid-solid separation is performed to obtain a germanium-rich solution and a leaching residue;

[0051] (4) Chlorination distillation: The chlorination distillation solution was added with concentrated hydrochloric acid to adjust the concentration to 9 mol / L, and distilled at 120°C for 1 hour to obtain germanium tetrachloride and distillation residue;

[0052] (5) Recycling: The distillation residue is diluted to a solution concentration of 2 mol / L and then returned to the oxygen pressure leaching process.

[0053] Comparative Example 1:

[0054] The method is the same as Example 2, except that the atmosphere-controlled reduction, sulfidation and volatilization process in step (2) is omitted, and the germanium-containing material is directly subjected to oxygen pressure leaching treatment.

[0055] Comparative Example 2:

[0056] The method is the same as Example 2, except that: step (3) oxygen pressure leaching is omitted, and chlorination distillation is directly carried out on the germanium-arsenic-rich smoke.

[0057] The results of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0058] Table 1

[0059]

[0060] As can be seen from Table 1, the combined method of controlled atmosphere reduction sulfidation volatilization and oxygen pressure leaching can achieve efficient directional separation of germanium and arsenic (germanium enters the solution in the form of soluble ions, and arsenic enters the precipitate slag in the form of ferric arsenate). On the other hand, it can achieve efficient dissolution of germanium in vortex furnace dust, breaking through the technical bottleneck of difficult dissolution of silicon-germanium solid solution and tetragonal germanium dioxide.

[0061] Example 4:

[0062] The present invention is the same as Example 1, except that: in step (1), the vortex furnace dust containing germanium is mixed with the vulcanization aid in a mass ratio of 1:0.10; in step (2), the germanium-containing material is volatilized for 2 hours under a protective atmosphere and a temperature of 1200°C; and the conditions for the oxygen pressure leaching treatment in step (3) are as follows: the concentration of HCl in the mixed solution of HCl and FeCl2 is 1 mol / L, the mass of FeCl2 is 0.05 times the mass of the germanium-arsenic-rich dust, the liquid-to-solid ratio of the mixed solution to the germanium-arsenic-rich dust is 4 mL / g, the temperature is 80°C, the oxygen partial pressure is 0.2 MPa, and the reaction is carried out for 5 hours.

[0063] Example 5:

[0064] The present invention is the same as Example 1, except that: in step (1), the vortex furnace dust containing germanium is mixed with the vulcanization aid in a mass ratio of 1:0.25; in step (2), the germanium-containing material is volatilized for 8 hours under a protective atmosphere and a temperature of 1000°C; and the conditions for the oxygen pressure leaching treatment in step (3) are as follows: the concentration of HCl in the mixed solution of HCl and FeCl2 is 2 mol / L, the mass of FeCl2 is 0.20 times the mass of the germanium-arsenic-rich dust, the liquid-to-solid ratio of the mixed solution to the germanium-arsenic-rich dust is 7.5 mL / g, the temperature is 150°C, the oxygen partial pressure is 0.5 MPa, and the reaction is carried out for 2 hours.

[0065] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for efficiently enriching germanium by treating vortex furnace dust, characterized in that: The steps include: (1) Material preparation: The germanium-containing vortex furnace dust and the vulcanization accelerator are uniformly mixed in a mass ratio of 1:0.10 to 0.25 to obtain a germanium-containing material, wherein the vulcanization accelerator is calcium sulfate; (2) atmosphere-controlled reduction, sulfidation and volatilization: volatilizing the germanium-containing material obtained in step (1) in a nitrogen atmosphere at a temperature of 1000° C. to 1200° C. for 2 to 8 hours, and collecting the dust to obtain germanium-arsenic-rich smoke and volatile residue; (3) oxygen pressure leaching: the germanium-arsenic-rich smoke dust obtained in step (2) is subjected to oxygen pressure leaching treatment, and liquid-solid separation is performed to obtain a germanium-rich solution and a leaching residue, wherein the conditions of the oxygen pressure leaching treatment are as follows: the concentration of HCl in the mixed solution of HCl and FeCl2 is 1-2 mol / L, the mass of FeCl2 is 0.05-0.20 times the mass of the germanium-arsenic-rich smoke dust, the liquid-solid ratio of the mixed solution to the germanium-arsenic-rich smoke dust is 4-7.5 mL / g, the temperature is 80°C-150°C, the oxygen partial pressure is 0.2-0.5 MPa, and the reaction is carried out for 2-5 hours; (4) Chlorination distillation: The germanium-rich solution obtained in step (3) is added with concentrated hydrochloric acid to adjust the hydrochloric acid concentration to 8-10 mol / L, and distilled at a temperature of 110° C. to 120° C. for 0.5-4.0 h to obtain germanium tetrachloride and distillation residue; (5) Recycling: The distillation residue is diluted to a hydrochloric acid solution concentration of 1 to 2 mol / s and then returned to the oxygen pressure leaching process to treat the germanium-arsenic-rich smoke dust with oxygen pressure leaching.

2. The method according to claim 1, characterized in that The vortex furnace dust described in step (1) includes the following components: Ge 0.25-1.50wt.%, C 5-20wt.%, S1-5wt.%, Si 5-25wt.%, As 0.25-5.00wt.%, and Ca1-10wt.%.

3. The method according to claim 1 or 2, characterized in that The germanium-containing vortex furnace dust described in step (1) is evenly mixed with a vulcanization aid in a mass ratio of 1:0.15-0.25 to obtain a germanium-containing material.

4. The method according to claim 1 or 2, characterized in that The germanium-containing material described in step (2) is volatilized for 3 to 5 hours under a nitrogen atmosphere at a temperature of 1050° C. to 1200° C., and then dust is collected to obtain germanium-arsenic-rich smoke and volatile residue.

5. The method according to claim 1, wherein The conditions for the oxygen pressure leaching treatment in step (3) are as follows: the concentration of HCl in the mixed solution of HCl and FeCl2 is 1.2 to 2.0 mol / L, the mass of FeCl2 is 0.10 to 0.15 times the mass of the germanium-arsenic-rich smoke dust, the liquid-to-solid ratio of the mixed solution to the germanium-arsenic-rich smoke dust is 4 to 6 mL / g, the temperature is 100° C. to 120° C., the oxygen partial pressure is 0.2 to 0.3 MPa, and the reaction is carried out for 2 to 4 hours.

6. The method according to claim 1 or 2, characterized in that The specific steps of step (4) are as follows: adding concentrated hydrochloric acid to the germanium-rich solution obtained in step (3) to adjust the hydrochloric acid concentration to 8-9 mol / L, and distilling at a temperature of 110° C. to 120° C. for 1-2 hours to obtain germanium tetrachloride and distillation residue.

7. The method according to claim 1 or 2, characterized in that The distillation residue in step (5) is diluted to a hydrochloric acid solution concentration of 1.2 to 2.0 mol / s and then returned to the oxygen pressure leaching process.

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