CN-121976050-A - Method for preparing high-purity silver powder by recycling silver from retired photovoltaic module

Abstract

The invention relates to a silver recovery technology, in particular to a method for preparing high-purity silver powder by recovering silver from retired photovoltaic module battery pieces, which comprises the procedures of pretreatment, leaching treatment, suction filtration treatment, silver precipitation treatment, silver chloride precipitation purification treatment, silver ammonia solution reduction and the like. The method comprises the steps of taking disassembled retired photovoltaic module battery pieces as raw materials, firstly removing dust on the surfaces of the battery pieces and part of metal impurities attached to the surfaces of the battery pieces through pretreatment, leaching the cleaned battery pieces by using nitric acid solution, carrying out suction filtration by using a suction filter, separating to obtain silicon slag and silver nitrate solution, adding a chlorinating agent into the silver nitrate solution, reacting to generate silver chloride precipitate, dissolving the separated silver chloride precipitate by using ammonia water to form silver-ammonia solution, and finally adding a reducing agent into the silver-ammonia solution to obtain high-purity silver powder and ammonia water.

Inventors

• LI GUANGMEI
• CAI XIN
• TAN LIN
• LIU YI
• LIU WEI
• LUO XUAN
• TAN XIN
• KANG RULONG
• ZHANG XIN
• ZHAO YI
• ZHANG JIANFENG
• BAO LIPING
• ZOU GUANGQING
• CAO XIANG
• HE TIANQI

Assignees

• 湖南白银股份有限公司
• 郴江实验室

Dates

Publication Date

20260505

Application Date

20260121

Claims (7)

1. 1. The method for preparing the high-purity silver powder by recycling silver from the retired photovoltaic module is characterized by comprising the following steps of: Step one, preprocessing, namely physically cleaning a battery piece in the retired photovoltaic module to remove dust and impurity metals adhered to the surface of the battery piece; leaching, namely leaching the battery piece by using a nitric acid solution, and reacting to generate a silver nitrate solution, nitrogen oxides and water; Step three, carrying out suction filtration treatment, and after leaching treatment, carrying out suction filtration by using a suction filter to separate leaching residues and leaching liquid; Step four, silver precipitation treatment, namely adding a chlorinating agent into leaching solution after suction filtration treatment, reacting to generate silver chloride precipitate and silver precipitation solution containing excessive chloride ions, and separating out the silver chloride precipitate; And step six, reducing the silver-ammonia solution, and adding a reducing agent into the silver-ammonia solution to obtain high-purity silver powder and ammonia water.
2. 2. The method for preparing high-purity silver powder by recovering silver from a retired photovoltaic module according to claim 1, wherein in the second step, nitrogen oxides generated by the reaction are oxidized by a hydrogen peroxide pre-washing tower, and unabsorbed waste gas enters a secondary alkaline washing tower for treatment.
3. 3. The method for preparing high-purity silver powder by recovering silver from a retired photovoltaic module according to claim 1, wherein in the fourth step, a filtrate of a silver precipitation solution is obtained after precipitation is separated, the filtrate is returned to the second step for recycling, and the silver chloride precipitate obtained after separation is washed by washing water, and the washing water is reused.
4. 4. The method for preparing high-purity silver powder by recovering silver from retired photovoltaic modules according to claim 3, wherein in the fourth step, the chlorinating agent is industrial sodium chloride, and the process system for adding the chlorinating agent is in a heating and heat-preserving state.
5. 5. The method for preparing high-purity silver powder by recovering silver from a retired photovoltaic module according to claim 3, wherein in the fourth step, the concentration of the non-precipitated free impurity metal ions in the filtrate of the silver precipitation solution is continuously increased along with the increase of the cycle number, and when the concentration exceeds a preset value, the circulating route is subjected to open-circuit treatment to recover the impurity metal ions in the filtrate of the silver precipitation solution.
6. 6. The method for preparing high-purity silver powder by recovering silver from a retired photovoltaic module according to claim 5, wherein the open-circuit treatment is that when the concentration of metal ions in the filtrate of the silver precipitation solution reaches a preset value, slowly adding sodium hydroxide solution into the filtrate while continuously stirring to accurately adjust the pH value of the solution to 4; Slowly adding sodium hydroxide solution, regulating pH to 7-8, filtering to obtain blue precipitate, adding sodium carbonate solution into the filtrate to obtain white precipitate, standing, settling, filtering to obtain residue mixture, and processing the filtrate with harmless salt solution.
7. 7. The method for preparing high-purity silver powder by recycling silver from retired photovoltaic modules according to claim 1, wherein in the sixth step, the reducing agent is glucose, and generated ammonia water is recycled and circularly drained to the fifth step.

Description

Method for preparing high-purity silver powder by recycling silver from retired photovoltaic module Method for preparing high-purity silver powder by recovering silver from retired photovoltaic module battery piece Technical Field The invention relates to a silver recovery technology, in particular to a method for preparing high-purity silver powder by recovering silver from retired photovoltaic module battery pieces. Background Recovery of valuable metals in retired photovoltaic modules has become a significant challenge for the industry. At present, a plurality of researches are carried out on comprehensive recycling of photovoltaic modules by students at home and abroad, wherein a great deal of disassembly and separation researches are mainly carried out on frames of retired photovoltaic modules, disassembly of junction boxes, removal of EVA (ethylene vinyl acetate) adhesive, glass recycling and back plate removal. After the retired photovoltaic module is disassembled and separated, a retired photovoltaic module battery piece is obtained, the main components of the retired photovoltaic module battery piece are silicon and silver, and a small amount of aluminum, copper, magnesium and other impurity elements exist, wherein the silver has higher economic recovery value. Silver is used as the key metal with the highest value in the photovoltaic module, and the recovery meaning of the silver is great. Patent CN118531221a discloses a method for recovering silver from retired photovoltaic modules, which uses choline chloride as a leaching agent to recover silver and aluminum on the surface of the photovoltaic modules, after leaching, filtering, concentrating leaching liquid after secondary leaching of leaching residue, adding ammonia water to remove impurities from the concentrated liquid, adding hydrochloric acid into the filtrate after filtering to obtain silver chloride precipitate at a higher speed, and finally directly adopting hydrazine hydrate to reduce silver chloride to obtain sponge silver products. In the method, hydrazine hydrate has extremely strong reducibility, so that the reaction speed of reducing silver is extremely high, a sponge silver product with roughness, looseness and nonuniform particles is generated, and high-purity silver powder cannot be generated. Patent CN115786713a discloses a method for recovering silver and aluminum in solar panels, which uses a mixed solution of methanesulfonic acid and hydrogen peroxide to leach silver and aluminum in waste solar panels through a heat treatment system, an acid leaching system, a silver chloride precipitation system, a crude silver powder recovery system. Patent CN110404944a discloses a device for separating, purifying and recovering battery materials in a crystalline silicon photovoltaic module, which mainly adopts a process of removing aluminum by sodium hydroxide, leaching silver by nitric acid and removing silicon nitride by hydrofluoric acid. The recovery research of the retired photovoltaic module battery piece by the above patent is less, the existing patent recovery silver process is complex, the choline chloride or calcium chloride is used for silver precipitation, the cost is high, and the wastewater treatment is difficult. The invention overcomes the defects in the background art, provides a method for efficiently and economically recycling silver from the retired component battery piece and preparing high-purity silver powder, and aims to realize high-value utilization of the retired photovoltaic component battery piece. Disclosure of Invention The invention aims to provide a method for preparing high-purity silver powder by recovering silver from retired photovoltaic module battery pieces. In order to achieve the above purpose, the present invention provides the following technical solutions: A method for preparing high-purity silver powder by recovering silver from retired photovoltaic module battery pieces comprises the following steps: Step one, preprocessing, namely physically cleaning a battery piece in the retired photovoltaic module to remove dust and impurity metals adhered to the surface of the battery piece; leaching, namely leaching the battery piece by using a nitric acid solution, and reacting to generate a silver nitrate solution, nitrogen oxides and water; Step three, carrying out suction filtration treatment, and after leaching treatment, carrying out suction filtration by using a suction filter to separate leaching residues and leaching liquid; Step four, silver precipitation treatment, namely adding a chlorinating agent into leaching solution after suction filtration treatment, reacting to generate silver chloride precipitate and silver precipitation solution containing excessive chloride ions, and separating out the silver chloride precipitate; And step six, reducing the silver-ammonia solution, and adding a reducing agent into the silver-ammonia solution to obtain high-purity silver powder and ammonia water. In