Method for extracting germanium by acid roasting

Abstract

Disclosed in the present invention is a method for extracting germanium by acid roasting. The method comprises acid roasting and post-treatment, and specifically comprises: adding an acid into coal ash for slurry mixing to obtain a material a; heating the material a to 350°C-800°C, and carrying out heat preservation for 10 min to 10 h to obtain an acid melt b; grinding the acid melt b until more than 60% of the acid melt b has a granularity of -200 meshes to obtain a material c; distilling the material c to obtain a residual slurry d and a distillate fraction e; and hydrolyzing the distillate fraction e by using a diluted hydrochloric acid solution, and then carrying out drying to obtain GeO2. The method mainly controls the trend of metal element Ge, achieves effective extraction of Ge, has a simple process flow easy to operate, and has high direct recovery rate of Ge and remarkable economic benefits.

Description

A method for extracting germanium by acid burning Technical Field

[0001] The invention belongs to the technical field of mining engineering, and in particular relates to a method for extracting germanium by acid burning. Background Art

[0002] The main methods for extracting germanium (Ge) at home and abroad currently include classical chlorination, volatilization, zinc exchange, distillation (alkaline earth metal chloride distillation), fuming, extraction (liquid membrane extraction), and ion exchange. However, classical chlorination, zinc exchange, extraction (liquid membrane extraction), and ion exchange all rely on extracting, separating, and enriching Ge from enriched Ge raw materials (flue dust or a Ge-containing aqueous solution). Germanium oxide in power plant coal ash exists as tetragonal and hexagonal Ge, while Germanium compounds exist as iron, calcium, and zinc germanate, with some occurring as solid solutions such as SiO2·GeO2 and Al2O3·GeO2. Due to the diverse crystal structures, complex components, and intercalated phases, conventional acid-base leaching and reductive volatilization methods struggle to efficiently enrich Ge, resulting in low recovery rates. Therefore, developing a method that can address these technical challenges is crucial. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for extracting germanium by acid calcination, wherein the germanium grade in coal ash is low and the method is for efficiently dissolving and dissociating multi-component, multi-structure, and multi-phase Ge materials. The method mainly controls the direction of the metallic element Ge to achieve effective extraction of Ge. The process flow is simple and easy to operate, the direct yield of Ge is high, and the economic benefits are significant. The present invention comprises: (1) adding an acid (H2SO4, H3PO4, etc.) and an oxidant (KMnO4, MnO2, NaNO3, etc.) to coal ash for melt calcination; (2) The acid-melted coal ash is mechanically crushed (-200 mesh > 60%); (3) The crushed acid-melted material is distilled to obtain distillation fraction I and residual pulp, and the residual pulp is filtered and washed to obtain washing residue I and washing liquid II; (4) Washing residue I is then mixed with alkali (NaOH, KOH, Na2CO3, K2CO3, etc.) for melting and calcining; (5) The alkali-melted material is crushed; (6) The crushed alkali-melted material is water-soaked, filtered and washed to obtain washing residue II and washing liquid III, and the water-soaked washing residue II is stored; (7) Distillation fraction I is hydrolyzed and dried to obtain GeO2; (8) Washing liquid II and washing liquid III are neutralized and precipitated to obtain neutralization residue III and neutralization liquid IV, and neutralization liquid IV is returned as washing liquid to the water-soaked residue washing and residual pulp residue washing, and neutralization residue III is returned to chlorination distillation. This method has a simple process flow and is easy to operate. Germanium in coal ash can be efficiently dissociated and enriched.

[0004] Alternatively, the following steps are performed: (1) the coal ash is mixed with an acid (H2SO4, H3PO4, etc.) and an oxidant (KMnO4, MnO2, NaNO3, etc.) for melt calcination; (2) the acid-melted coal ash is mechanically crushed (-200 mesh > 60%); (3) the crushed acid-melted material is distilled to obtain a distillation fraction I and a residual pulp, which is then filtered and washed to obtain a washing residue I and a washing liquid II; (4) the washing residue I is mixed with an alkali (NaOH, KOH, etc.) for pressure leaching; (5) the pressure leached material is filtered and washed to obtain a washing residue II and a washing liquid III, which is then stored; (6) the distillation fraction I is hydrolyzed and dried to obtain GeO2; (7) the washing liquid II and the washing liquid III are neutralized and precipitated to obtain a neutralized residue III and a neutralized liquid IV, which is returned as a washing liquid to the water leaching residue washing and the residual pulp residue washing, and the neutralized residue III is returned to the chlorination distillation. The method has a simple process flow and is easy to operate, and can achieve efficient dissociation and enrichment of germanium in coal ash.

[0005] The object of the present invention is achieved by comprising acid burning and a post-processing step, specifically comprising:

[0006] A. Acid burning:

[0007] 1) Adding acid to the fly ash to prepare a slurry to obtain material a;

[0008] 2) Heating material a to 350°C~800°C and keeping the temperature for 10 min~10 h to obtain acid melt material b;

[0009] B. Post-processing:

[0010] 1) Grind the acid melt material b to a particle size of -200 mesh > 60% to obtain material c;

[0011] 2) distilling material c to obtain residual slurry d and distillation fraction e;

[0012] 3) hydrolyzing the distillation fraction e with a dilute hydrochloric acid solution and then drying to obtain GeO2;

[0013] 4) filtering and washing the residual pulp d to obtain a washing residue f and a residual pulp mixed liquid g; the residual pulp mixed liquid g is composed of the distillation residue and the residual washing liquid;

[0014] 5) adding alkali to the washed slag f, raising the temperature to 350°C-1000°C, and maintaining the temperature for 10 minutes-10 hours to perform alkali calcination to obtain an alkali melt h, grinding the alkali melt h to a particle size of -200 mesh>60% to obtain material i, adding water 1-20 times the solid-liquid volume of material i to material i, stirring and soaking the material i at a temperature of 10°C-100°C for 0.5 hours-10 hours, filtering and washing to obtain water-soaked washed slag j and water-soaked mixed liquid k; the water-soaked mixed liquid k consists of water-soaked liquid and water-soaked slag washing liquid; neutralizing the water-soaked mixed liquid k with the residual pulp mixed liquid g to obtain a neutralized slag and a neutralized liquid; and returning the neutralized liquid to the filtering and washing step; or

[0015] After adding alkali to the washed residue f, pressure alkali leaching is performed, and then filtered and washed to obtain washed residue l and alkali leaching mixed liquid m, the alkali mixed leaching liquid m and the residual pulp mixed liquid g are neutralized to obtain neutralized residue and neutralized liquid; the neutralized liquid is returned to the filtering and washing step.

[0016] The specific operations are as follows:

[0017] (1) First, 0.1%~80% H2SO4 is used to prepare the slurry in the coal ash. During the slurry preparation process, 0.1%~40% (based on the mass of the coal ash) H3PO4 and 0.1%~20% (based on the mass of the coal ash) KMnO4 / MnO2 / NaNO3 can also be added.

[0018] (2) Acid fusion of acid-adjusted coal ash. The acid fusion temperature is 350℃~800℃, and the maximum temperature residence time is 10min~10h.

[0019] (3) The acid melt material is wet ball milled, rod milled or sand milled, and the particle size requirement is -200 mesh>60%.

[0020] (4) Distillation of crushed acid slag. Distillation conditions: distillation temperature 80℃~200℃, distillation l:s ratio 1:1~5:1, HCl concentration 6 mol / L~12 mol / L, distillation end point pH <0.5. The distillate can be mixed with 0.1%~20% NaCl / KCl (based on the mass of the acid slag) and 0.1%~20% H3PO4 / H2O2 / KMnO4 (based on the mass of the acid slag).

[0021] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid are mixed to obtain a residue mixed liquid. The pH value of the washing liquid is less than 0.5, and the washing liquid is prepared with HCl.

[0022] (6) Add alkali (NaOH, KOH, Na2CO3, K2CO3) to the distillation slag. The amount of alkali used should be 1.0 to 10 times the amount of the distillation slag (based on the mass of the distillation slag). The alkali melting temperature is 350°C to 1000°C, and the maximum temperature residence time is 10 minutes to 10 hours. When alkali calcining, first mix half of the alkali and fly ash into the crucible, and then cover the surface of the mixture with the remaining half of the alkali.

[0023] (7) Alkali melt wet ball milling, rod milling or sand milling, the particle size requirement is -200 mesh> 60%.

[0024] (8) The crushed alkali melt is immersed in water. The immersion process conditions are as follows: the immersion temperature is room temperature to 100 °C, the liquid-solid ratio is 1:1~20:1, the time is 0.5h~10h, the mechanical stirring speed is 20r / min~1000r / min, and the pH value at the end of the immersion is >13.5.

[0025] (9) After water immersion, the mixture is filtered and washed, and the filtrate is mixed with the washing liquid to obtain a water immersion mixture; the pH value of the water immersion washing liquid is greater than 13.5, and the washing liquid is prepared with a base having the same cation as the base used in alkali fusion.

[0026] (10) Neutralize the water-soaked mixture and the residual pulp mixture to a pH of 1 to 4.1.

[0027] (11) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0028] Or do the following:

[0029] (1) First, 0.1%~80% H2SO4 is used to prepare the slurry in the coal ash. During the slurry preparation process, 0.1%~40% (based on the mass of the water-leached residue) of H3PO4 and 0.1%~20% (based on the mass of the coal ash) of KMnO4 / MnO2 / NaNO3 can also be added.

[0030] (2) Acid fusion of acid-adjusted coal ash. The acid fusion temperature is 350℃~800℃, and the maximum temperature residence time is 10min~10h.

[0031] (3) The acid melt material is wet ball milled, rod milled or sand milled, and the particle size requirement is -200 mesh>60%.

[0032] (4) Distillation of crushed acid slag. Distillation conditions: distillation temperature 80℃~200℃, distillation l:s 1:1~5:1, HCl concentration 6 mol / L~12 mol / L, distillation end point pH <0.5. The distillate can be mixed with 0.1%~20% NaCl / KCl (based on the mass of the acid slag) and 0.1%~20% H3PO4 / H2O2 / KMnO4 (based on the mass of the acid slag).

[0033] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid are mixed to obtain a residue mixed liquid. The pH value of the washing liquid is less than 0.5, and the washing liquid is prepared with HCl.

[0034] (6) Add alkali (NaOH, KOH, LiOH, choline (HOCH2CH2N(CH3)3(OH)), quaternary ammonium alkali (NR4OH), sodium alcoholate, etc.) to the distilled residue and then leaching it under pressure. Alkali leaching conditions: alkali leaching temperature 100℃~200℃, time 0.1h~10h, l:s=1:1~20:1, alkali concentration 10g / L~400g / L, mechanical stirring speed 20r / min~1000r / min, alkali leaching end point pH value>13.5.

[0035] (7) After alkali leaching, the mixture is filtered and washed, and the filtrate is mixed with the washing liquid to obtain a water leaching mixture; the pH value of the alkali leaching liquid is greater than 13.5, and the washing liquid is prepared with a base having the same cation as the base used in the alkali dissolution.

[0036] (8) Neutralize the alkaline leaching mixture and the residual pulp mixture to a pH of 1~4.1.

[0037] (9) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG1 is a schematic diagram of the process flow of the present invention;

[0039] FIG2 is another process flow diagram of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described below with reference to the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention fall within the scope of protection of the present invention.

[0041] The method for extracting germanium by acid burning according to the present invention comprises acid burning and post-processing steps, specifically comprising:

[0042] A. Acid burning:

[0043] 1) Adding acid to the fly ash to prepare a slurry to obtain material a;

[0044] 2) Heating material a to 350°C~800°C and keeping the temperature for 10 min~10 h to obtain acid melt material b;

[0045] B. Post-processing:

[0046] 1) Grind the acid melt material b to a particle size of -200 mesh > 60% to obtain material c;

[0047] 2) distilling material c to obtain residual slurry d and distillation fraction e;

[0048] 3) hydrolyzing the distillation fraction e with a dilute hydrochloric acid solution and then drying to obtain GeO2;

[0049] 4) filtering and washing the residual pulp d to obtain a washing residue f and a residual pulp mixed liquid g; the residual pulp mixed liquid g is composed of the distillation residue and the residual washing liquid;

[0050] 5) adding alkali to the washed slag f, raising the temperature to 350°C-1000°C, and maintaining the temperature for 10 minutes-10 hours to perform alkali calcination to obtain an alkali melt h, grinding the alkali melt h to a particle size of -200 mesh>60% to obtain material i, adding water 1-20 times the solid-liquid volume of material i to material i, stirring and soaking the material i at a temperature of 10°C-100°C for 0.5 hours-10 hours, filtering and washing to obtain water-soaked washed slag j and water-soaked mixed liquid k; the water-soaked mixed liquid k consists of water-soaked liquid and water-soaked slag washing liquid; neutralizing the water-soaked mixed liquid k with the residual pulp mixed liquid g to obtain a neutralized slag and a neutralized liquid; and returning the neutralized liquid to the filtering and washing step; or

[0051] After adding alkali to the washed residue f, pressure alkali leaching is performed, and then filtered and washed to obtain washed residue l and alkali leaching mixed liquid m, the alkali mixed leaching liquid m and the residual pulp mixed liquid g are neutralized to obtain neutralized residue and neutralized liquid; the neutralized liquid is returned to the filtering and washing step.

[0052] A. The acid described in step 1) is H2SO4.

[0053] The amount of the acid added is 0.1% to 80% of the mass of the coal ash.

[0054] The slurry preparation in step A also includes adding 0.1% to 40% of the mass of the water-washed slag c in H3PO4 and 0.1% to 20% of the mass of the water-washed slag c in KMnO4, MnO or NaNO3.

[0055] The distillation conditions in step B2) are as follows: distillation temperature 80°C to 200°C, distillation l:s (ratio of liquid volume to solid mass during distillation) 1:1 to 5:1, HCl concentration 6 mol / L to 12 mol / L, and distillation endpoint pH <0.5.

[0056] B. The concentration of the dilute hydrochloric acid solution in step 3) is 1 mol / L to 3 mol / L.

[0057] B. The alkali calcination in step 5) is performed by first mixing half of the alkali and fly ash to obtain a mixture which is poured into a crucible, and then covering the surface of the mixture with the other half of the alkali for alkali calcination.

[0058] B. The stirring speed of the water immersion in step 5) is 20 r / min~1000 r / min.

[0059] B. Alkali leaching conditions described in step 5) are: alkali leaching temperature 100°C~200°C, time 0.1~10h, l:s=1:1~20:1, alkali concentration 10g / L~400g / L, mechanical stirring speed 20r / min~1000r / min, and alkali leaching endpoint pH value>13.5.

[0060] B. Step 5) The alkali in the alkali calcination is one or more of NaOH, KOH, Na2CO3, and K2CO3; the alkali in the alkali leaching is one or more of NaOH, KOH, LiOH, choline (HOCH2CH2N(CH3)3(OH)), quaternary ammonium hydroxide (NR4OH), and sodium alkoxide.

[0061] The present invention will be further described below with reference to specific implementation cases:

[0062] Example 1

[0063] (1) 100g of coal ash (containing 3657g / t of germanium) is slurried with 55g of 98% concentrated H2SO4. During the slurry mixing process, 20% (based on the mass of the coal ash) of H3PO4 and 50% (based on the mass of the coal ash) of KMnO4 are added.

[0064] (2) Acid fusion of acid-adjusted coal ash. Acid fusion temperature is 650°C, and the maximum temperature residence time is 1 hour.

[0065] (3) Rod milling of acid melt, speed 100r / min, time 1h. The particle size after rod milling is -200 mesh>75%.

[0066] (4) Distill 142 g of the crushed acid melt under the following conditions: distillation temperature 140°C, distillation l:s ratio 3.6:1, HCl concentration 7 mol / L, and pH value < 0.5 at the end of distillation. The distillate can be mixed with 20% NaCl (based on the mass of the acid melt) and 2% KMnO4 (based on the mass of the acid melt).

[0067] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid (HCl concentration 20 g / L) are mixed to obtain a residue mixture.

[0068] (6) 50g of the distilled washed residue was added to 75g of NaOH for alkali melting. The alkali melting temperature was 650°C, and the maximum temperature residence time was 1h. During alkali burning, half of the alkali and fly ash mixture was poured into the crucible, and the remaining half of the alkali was used to cover the surface of the mixture.

[0069] (7) Rod milling of alkali melt, speed 100r / min, time 1h. The particle size after rod milling is -200 mesh>78%.

[0070] (8) 135 g of the crushed alkali melt was soaked in water. The soaking process conditions were as follows: the soaking temperature was from room temperature to 85 °C, the liquid-solid ratio was 4:1, the soaking time was 1.5 h, the mechanical stirring speed was 180 r / min, and the pH value at the end of the soaking was >13.5.

[0071] (9) After water immersion, filter and wash, and mix the filtrate with the washing liquid to obtain a water immersion mixture. The washing liquid is a 15g / L NaOH solution.

[0072] (10) Neutralize the water-soaked mixture and the residual pulp mixture to a pH of 1~2.

[0073] (11) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0074] (12) After extraction, separation and enrichment of coal ash, the germanium content was reduced from 3657 g / t in coal ash to 281 g / t in water-washed slag, and the recovery rate of germanium reached 99.91%.

[0075] Example 2

[0076] (1) 100g of coal ash (containing 3657g / t of germanium) is slurried with 55g of 98% concentrated H2SO4. During the slurry mixing process, 20% (based on the mass of the coal ash) of H3PO4 and 5% (based on the mass of the coal ash) of KMnO4 are added.

[0077] (2) Acid fusion of acid-adjusted coal ash. Acid fusion temperature is 750°C, and the maximum temperature residence time is 1 hour.

[0078] (3) Ball mill the acid melt at a speed of 400 r / min for 1 h. The particle size after ball milling is -200 mesh > 83%.

[0079] (4) Distill 139.19 g of the crushed acid melt under the following conditions: distillation temperature 140°C, distillation l:s ratio 3.6:1, HCl concentration 8.9 mol / L, and pH value < 0.5 at the end of distillation. The distillate can be mixed with 48% H3PO4 (based on the mass of the acid melt) and 7% KMnO4 (based on the mass of the acid melt).

[0080] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid (HCl concentration 20 g / L) are mixed to obtain a residue mixture.

[0081] (6) 50g of the distilled washed residue was added to 125g of NaOH for alkali melting. The alkali melting temperature was 650°C, and the maximum temperature residence time was 1h. During alkali burning, half of the alkali and fly ash mixture was poured into the crucible, and the remaining half of the alkali was used to cover the surface of the mixture.

[0082] (7) Ball mill the alkali melt at a speed of 400 r / min for 1 h. The particle size after ball milling is -200 mesh > 82%.

[0083] (8) 141 g of the crushed alkali melt was soaked in water. The soaking process conditions were as follows: the soaking temperature ranged from room temperature to 85 °C, the liquid-solid ratio was 4:1, the soaking time was 1 h, the mechanical stirring speed was 180 r / min, and the pH value at the end of the soaking was >13.5.

[0084] (9) After water immersion, filter and wash, and mix the filtrate with the washing liquid to obtain a water immersion mixture. The washing liquid is a 15g / L NaOH solution.

[0085] (10) Neutralize the water-soaked mixture and the residual pulp mixture to a pH of 1~2.

[0086] (11) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0087] (12) After extraction, separation and enrichment of coal ash, the germanium content was reduced from 3657 g / t in coal ash to 146.5 g / t in water-washed slag, and the germanium recovery rate reached 98.88%.

[0088] Example 3

[0089] (1) 100g of coal ash (containing 3657g / t of germanium) is slurried with 55g of 98% concentrated H2SO4. During the slurry mixing process, 20% (based on the mass of the coal ash) of H3PO4 and 10% (based on the mass of the coal ash) of KMnO4 are added.

[0090] (2) Acid fusion of acid-adjusted coal ash. Acid fusion temperature is 630°C, and the maximum temperature residence time is 30 minutes.

[0091] (3) Sand grinding of acid melt, speed 1000r / min. The particle size after sand grinding is -200 mesh>99%.

[0092] (4) 141.97 g of the crushed acid melt was distilled under the following conditions: distillation temperature 140 °C, distillation l:s 3.6:1, HCl concentration 6 mol / L, and distillation end point pH < 0.5.

[0093] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid (HCl concentration 20 g / L) are mixed to obtain a residue mixture.

[0094] (6) 50g of the distilled washed slag was added to 100g of Na2CO3 for alkali melting. The alkali melting temperature was 650°C, and the maximum temperature residence time was 1h. During alkali burning, half of the alkali and fly ash mixture was poured into the crucible, and the remaining half of the alkali was used to cover the surface of the mixture.

[0095] (7) Sand grinding of alkali melt, speed 1000r / min. The particle size after sand grinding is -200 mesh>99%.

[0096] (8) 90.7 g of the crushed alkali melt was soaked in water. The soaking process conditions were as follows: the soaking temperature ranged from room temperature to 85 °C, the liquid-solid ratio was 4:1, the soaking time was 1.5 h, the mechanical stirring speed was 180 r / min, and the pH value at the end of the soaking was >13.5.

[0097] (9) After water immersion, filter and wash, and mix the filtrate with the washing liquid to obtain a water immersion mixture. The washing liquid is a 15g / L NaOH solution.

[0098] (10) Neutralize the water-soaked mixture and the residual pulp mixture to a pH of 1~2.

[0099] (11) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0100] (12) After extraction, separation and enrichment of coal ash, the germanium content was reduced from 3657 g / t in coal ash to 383.8 g / t in water-washed slag, and the recovery rate of germanium reached 99.85%.

[0101] Example 4

[0102] (1) 200g of coal ash (containing 3657g / t of germanium) is slurried with 110g of 98% concentrated H2SO4. During the slurrying process, 10% (based on the mass of the coal ash) of NaNO3 is added.

[0103] (2) Acid fusion of acid-adjusted coal ash. Acid fusion temperature is 650°C, and the maximum temperature residence time is 1 hour.

[0104] (3) Rod milling of acid melt, speed 100r / min, time 1h. The particle size after rod milling is -200 mesh>76%.

[0105] (4) Distill 100 g of the crushed acid melt under the following conditions: distillation temperature 145°C, distillation l:s ratio 5:1, HCl concentration 6 mol / L, and pH value < 0.5 at the end of distillation. The distillate can be mixed with 10% NaCl (based on the mass of the acid melt) and 17% 85% H3PO4 (based on the mass of the acid melt).

[0106] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid (HCl concentration 20 g / L) are mixed to obtain a residue mixture.

[0107] (6) 50 g (dry weight) of distilled washed residue was added with 160 g of NaOH. Leaching was carried out for 1 h at a liquid-to-solid ratio of 10:1, a pressure leaching temperature of 150 °C, and a stirring speed of 500 r / min.

[0108] (7) After pressurized alkaline leaching, filter and wash, and mix the filtrate with the washing liquid to obtain a water leaching mixture. The washing liquid is a 15g / L NaOH solution.

[0109] (8) Neutralize the alkaline leaching mixture and the residual pulp mixture to a pH of 1~3.

[0110] (9) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0111] (10) After extraction, separation and enrichment of coal ash, the germanium content was reduced from 3657 g / t in coal ash to 362 g / t in water-washed slag, and the recovery rate of germanium reached 97.52%.

[0112] Example 5

[0113] (1) 100g of fly ash (containing 3657g / t of germanium) is slurried with 55g of 98% concentrated H2SO4.

[0114] (2) Acid fusion of acid-adjusted coal ash. Acid fusion temperature is 650°C, and the maximum temperature residence time is 1 hour.

[0115] (3) Rod milling of acid melt, speed 100r / min, time 1h. The particle size after rod milling is -200 mesh>77%.

[0116] (4) Distill 100 g of the crushed acid melt under the following conditions: distillation temperature 138°C, distillation l:s ratio 5:1, HCl concentration 6 mol / L, and pH value < 0.5 at the end of distillation. The distillate can be mixed with 10% NaCl (based on the mass of the acid melt) and 68% 85% H3PO4 (based on the mass of the acid melt).

[0117] (5) The distillation residue is filtered and washed, and the distillation residue and the residue washing liquid (HCl concentration 20 g / L) are mixed to obtain a residue mixture.

[0118] (6) 60.37 g (dry weight) of distilled residue was added with 160 g of choline (HOCH2CH2N(CH3)3(OH)). Leaching was carried out for 1 h at a liquid-to-solid ratio of 10:1, a pressure leaching temperature of 120°C, and a stirring speed of 600 r / min.

[0119] (7) After pressurized alkaline leaching, filter and wash, and mix the filtrate with the washing liquid to obtain a water leaching mixture. The washing liquid is a 15g / L NaOH solution.

[0120] (8) Neutralize the alkaline leaching mixture and the residual pulp mixture to a pH of 2~3.

[0121] (9) The distilled fraction is hydrolyzed with a 2 mol / L dilute hydrochloric acid solution, and then filtered, washed, and dried to obtain germanium oxide.

[0122] (10) After extraction, separation and enrichment of coal ash, the germanium content was reduced from 3657 g / t in coal ash to 519 g / t in water-washed slag, and the germanium recovery rate reached 91.43%.

Claims

1. A method for extracting germanium by acid burning, characterized in that: It includes acid burning and post-treatment steps, specifically including: A. Acid burning: 1) Adding acid to the fly ash to prepare the slurry to obtain material a; 2) Heat material a to 350℃~800℃ and keep it warm for 10min~10h to obtain acid melt material b; B. Post-processing: 1) Grind the acid melt b to a particle size of -200 mesh>60% to obtain material c; 2) distilling material c to obtain residual slurry d and distillation fraction e; 3) hydrolyzing the distillation fraction e with a dilute hydrochloric acid solution, and then drying to obtain GeO2; 4) filtering and washing the residual pulp d to obtain washing residue f and residual pulp mixed liquid g; the residual pulp mixed liquid g is composed of distillation residue and residual washing liquid; 5) Add alkali to the washed slag f, raise the temperature to 350℃~1000℃, keep the temperature for 10min~10h, and calcine to obtain alkali melt h, grind the alkali melt h to a particle size of -200 mesh>60% to obtain material i, add water 1~20 times the solid-liquid volume of material i to material i, stir and soak in water at a temperature of 10℃~100℃ for 0.5h~10h, filter and wash to obtain water-soaked washed slag j and water-soaked mixed liquid k; the water-soaked mixed liquid k consists of water-soaked liquid and water-soaked slag washing liquid; the water-soaked mixed liquid k and the residual pulp mixed liquid g are neutralized to obtain neutralized slag and neutralized liquid; the neutralized liquid is returned to the filtering and washing step; or After adding alkali to the washed residue f, pressurized alkali leaching is performed, and then filtered and washed to obtain washed residue l and alkali leaching mixed liquid m, and the alkali mixed leaching liquid m and residual pulp mixed liquid g are neutralized to obtain neutralized residue and neutralized liquid; the neutralized liquid is returned to the filtering and washing step.

2. The method for extracting germanium by acid calcination according to claim 1, characterized in that: A. The acid described in step 1) is H2SO4.

3. The method for extracting germanium by acid calcination according to claim 1 or 2, characterized in that: The amount of the acid added is 0.1% to 80% of the mass of the coal ash.

4. The method for extracting germanium by acid calcination according to claim 1, characterized in that: The slurry preparation in step A also includes adding 0.1-40% of H3PO4 by weight of the water-washed slag c and 0.1-20% of KMnO4, MnO2 or NaNO3 by weight of the water-washed slag c.

5. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. The distillation conditions in step 2) are: distillation temperature 80°C~200°C, distillation l:s 1:1~5:1, HCl concentration 6 mol / L~12 mol / L, distillation endpoint pH <0.

5.

6. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. The concentration of the dilute hydrochloric acid solution in step 3) is 1 mol / L to 3 mol / L.

7. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. The alkali calcination in step 5) is to first mix half of the alkali and the fly ash to obtain a mixture which is poured into a crucible, and then cover the surface of the mixture with the other half of the alkali for alkali calcination.

8. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. In step 5), the stirring speed of the water immersion is 20 r / min~1000 r / min.

9. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. The alkali leaching conditions described in step 5) are: alkali leaching temperature 100°C~200°C, time 0.1h~10h, l:s=1:1~20:1, alkali concentration 10g / L~400g / L, mechanical stirring speed 20r / min~1000r / min, alkali leaching endpoint pH value>13.

5.

10. The method for extracting germanium by acid calcination according to claim 1, characterized in that: B. Step 5) The alkali described in alkali calcination is one or more of NaOH, KOH, Na2CO3, and K2CO3; the alkali described in alkali leaching is one or more of NaOH, KOH, LiOH, choline (HOCH2CH2N(CH3)3(OH)), quaternary ammonium hydroxide (NR4OH) and sodium alcoholate.

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