A process for recovering germanium from solar film solid waste

Abstract

The present invention provides a process for recovering germanium from solar film solid waste, characterized in that it comprises the following steps: raw material processing: crushing or shearing the film solid waste; digestion: first adding the reaction solution in the reactor, then adding the treated raw material, and stirring fully; conversion: adding a certain amount of sodium hydroxide, heating to above 90°C and stirring for 0.5h; precipitation and filtration: adding a certain amount of precipitant and water, then adding hydrochloric acid solution to neutralize to a pH value of 4.5-6.5, slowly stirring or standing, filtering to obtain a crude product; distillation: transferring the crude product to a distillation device, adding hydrochloric acid, and distilling to collect the product GeCl4. The method is simple in process, has low requirements for equipment conditions, low cost, and high germanium recovery rate.

Description

Technical Field

[0001] The invention relates to the technical field of germanium resource recovery, and in particular to a process for recovering germanium from solar film solid waste. Background Art

[0002] Germanium is a rare metal and an important semiconductor material. It has extensive and important applications in semiconductors, optical fibers, optics, catalysis, biomedicine and other fields. The global germanium resources are extremely scarce, with only about 8,600 tons in stock. Due to the importance of germanium, Western countries have established a relatively complete export and strategic reserve management system from the perspective of maintaining national and economic security. It is also because of the wide application of germanium and the shortage of reserves that my country has also raised the production and recycling of germanium to a strategic level.

[0003] Germanium resources are non-renewable. Although my country's germanium production is large, the recovery, application and development of germanium are still very limited, especially the recovery of germanium from germanium-containing waste. Recovering germanium from germanium-containing waste has significant economic significance and social benefits, but the current germanium recovery process is complex and the process conditions are very strictly controlled, resulting in high costs. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a process for recovering germanium from solar film solid waste.

[0005] The present invention is achieved in that:

[0006] The present invention provides a process for recovering germanium from solar film solid waste, comprising the following steps:

[0007] S1. Crush or shear the film solid waste;

[0008] S2, first add the reaction liquid into the reactor, then add the treated raw materials, and stir thoroughly;

[0009] S3, continue to add a certain amount of sodium hydroxide, raise the temperature to above 90°C and stir for a period of time to fully react;

[0010] S4, adding a certain amount of precipitant and water, and then adding acid to neutralize to a pH value of 4.5-6.5, slowly stirring or standing, and filtering to obtain a crude product;

[0011] S5. The crude product is transferred to a distillation apparatus, hydrochloric acid is added, and the product GeCl is collected by distillation.

[0012] Among various solar cell materials, due to the photoelectric conversion efficiency and cost issues, compared with silicon, germanium silicon has the advantages of lower process temperature, adjustable bandgap width, and full compatibility with existing photovoltaic cell process technology, and is relatively easy to achieve the goals of high efficiency and low cost. Therefore, germanium silicon solar film materials are an important direction for current and future development. Therefore, the recovery of germanium from the corresponding material processing scraps and waste has a good prospect, and the recycling and processing of thin film materials has certain particularities. The reactions involved in the present invention are as follows:

[0013] Ge+2NaClO+2NaOH→Na2GeO3+2NaCl+H2O

[0014] Na2GeO3+2HCl→GeO2↓+2NaCl+H2O

[0015] GeO2+4HCl→GeCl4+2H2O

[0016] Furthermore, the reaction solution is a solution of water and sodium hypochlorite in a ratio of 1:0.5 to 2.

[0017] Furthermore, the mass ratio of the reaction liquid to the treated raw material is 8-15:2-5.

[0018] Furthermore, the reactor is an open reaction tank.

[0019] Furthermore, in step S4, the mass ratio of the added precipitant to water is 0.001 to 0.1:100.

[0020] Furthermore, the precipitant is a mineral with a certain water solubility, including inorganic salts such as sodium, magnesium, and calcium.

[0021] The present invention has the following beneficial effects:

[0022] The present invention uses an aqueous solution containing a precipitant to precipitate and separate GeO2 under specific pH conditions, and finally recovers germanium resources in the form of a GeCl4 product by distillation. The process is simple, the equipment requirements are not high, the germanium recovery rate is high, the cost is low, and it is simpler and more efficient than other methods. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The process for recovering germanium from solar thin film solid waste in this embodiment has the following specific operating steps:

[0026] Raw material processing: The film solid waste is crushed into powder by a crusher;

[0027] Digestion: In an open reactor, first add 0.8 tons of reaction liquid (water: sodium hypochlorite ratio is 1:1.5), then add 200 kg of treated raw material powder and stir thoroughly;

[0028] Conversion: Add 45 kg of 35% sodium hydroxide aqueous solution, heat to above 90°C, maintain the temperature and stir for more than 0.5 h to obtain sodium silicate and sodium germanate solution;

[0029] Precipitation and filtration: Add 6 times the weight of an aqueous solution containing 0.001-0.1% of a precipitant, neutralize with hydrochloric acid solution to a pH of 4.5, slowly stir or let stand, and filter at 25-50°C to obtain a crude product;

[0030] Distillation: Transfer the crude product to a distillation apparatus, add 12 equivalents of hydrochloric acid, start distillation, and collect the product GeCl4.

[0031] Example 2

[0032] The process for recovering germanium from solar thin film solid waste in this embodiment has the following specific operating steps:

[0033] Raw material processing: Cut the film solid waste into small pieces through a shearing machine;

[0034] Digestion: In an open reactor, add 1.5 tons of reaction solution (water: sodium hypochlorite ratio is 1:1.5), then add 500 kg of treated raw material fragments and stir thoroughly;

[0035] Conversion: Add 35 kg of solid sodium hydroxide in batches, raise the temperature to above 90°C, maintain the temperature and stir for more than 0.5 h to obtain sodium silicate and sodium germanate solution;

[0036] Precipitation and filtration: Add 7 times the weight of an aqueous solution containing 0.01-0.1% of a precipitant, neutralize with hydrochloric acid solution to a pH of 6.5, slowly stir or let stand, and filter at 25-50°C to obtain a crude product;

[0037] Distillation: Transfer the crude product to a distillation apparatus, add 12 equivalents of hydrochloric acid, start distillation, and collect the product GeCl4.

[0038] Example 3

[0039] The process for recovering germanium from solar thin film solid waste in this embodiment has the following specific operating steps:

[0040] Raw material processing: The film solid waste is crushed into powder by a crusher;

[0041] Digestion: In an open reactor, add 1.2 tons of reaction solution (water: sodium hypochlorite ratio is 1:2), then add 350 kg of treated raw material fragments and stir thoroughly;

[0042] Conversion: Add 55 kg of 40% sodium hydroxide aqueous solution, raise the temperature to above 90°C, maintain the temperature and stir for more than 0.5 h to obtain sodium silicate and sodium germanate solution;

[0043] Precipitation and filtration: Add 7 times the weight of an aqueous solution containing 0.01-0.1% of a precipitant, neutralize with hydrochloric acid solution to a pH of 5.5, slowly stir or let stand, and filter at 25-50°C to obtain a crude product;

[0044] Distillation: Transfer the crude product to a distillation apparatus, add 8 equivalents of hydrochloric acid, start distillation, and collect the product GeCl4.

[0045] Example 4

[0046] The process for recovering germanium from solar thin film solid waste in this embodiment has the following specific operating steps:

[0047] Raw material processing: Cut the film solid waste into small pieces through a shearing machine;

[0048] Digestion: In an open reactor, add 1.0 ton of reaction solution (water: sodium hypochlorite ratio is 1:0.5), then add 300 kg of treated raw material fragments and stir thoroughly;

[0049] Conversion: Add 50 kg of 30% sodium hydroxide aqueous solution, raise the temperature to above 90°C, maintain the temperature and stir for more than 0.5 h to obtain sodium silicate and sodium germanate solution;

[0050] Precipitation and filtration: Add 8 times the weight of aqueous solution containing 0.01-0.1% precipitant, neutralize with hydrochloric acid solution to pH 6, slowly stir or let stand, filter at 25-50°C to obtain a crude product;

[0051] Distillation: Transfer the crude product to a distillation apparatus, add 10 equivalents of hydrochloric acid, start distillation, and collect the product GeCl4.

[0052] The precipitant used in the above embodiment of the present invention is a mineral with a certain water solubility, including but not limited to inorganic salts such as sodium, magnesium, and calcium, which are commonly used precipitants. The germanium resource recovery rate is calculated and determined based on the product output and the raw material detection value. Under optimal conditions, this data can reach 98%.

[0053] The present invention uses an aqueous solution containing a precipitant to precipitate and separate GeO2 under specific pH conditions, and finally recovers germanium resources in the form of a GeCl4 product by distillation. The process is simple, the equipment requirements are not high, the germanium recovery rate is high, the cost is low, and it is simpler and more efficient than other methods.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for recovering germanium from solar film solid waste, characterized in that: Includes the following step: S1. Crush or shear the film solid waste; S2, first add the reaction solution into the reactor, then add the treated raw materials, and stir them thoroughly; The reaction liquid is a solution of water and sodium hypochlorite in a ratio of 1:0.5~2; the mass ratio of the reaction liquid to the treated raw material is 8~15:2~5; S3, continue to add a certain amount of sodium hydroxide, raise the temperature to above 90°C and stir for a period of time to fully react; S4, adding a certain amount of precipitant and water, and then adding acid to neutralize to a pH value of 4.5-6.5, slowly stirring or standing, and filtering to obtain a crude product; the mass ratio of the precipitant to water is 0.001-0.1:100; S5, transferring the crude product to a distillation device, adding hydrochloric acid, and distilling to collect the product GeCl4; The precipitant is a mineral with a certain water solubility, including magnesium and calcium inorganic salts.

2. The process for recovering germanium from solar film solid waste as claimed in claim 1, characterized in that: The reactor is an open type reaction tank.