CN111732120A - Environment-friendly efficient production method of high-purity silver nitrate - Google Patents
Environment-friendly efficient production method of high-purity silver nitrate Download PDFInfo
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- CN111732120A CN111732120A CN202010555853.7A CN202010555853A CN111732120A CN 111732120 A CN111732120 A CN 111732120A CN 202010555853 A CN202010555853 A CN 202010555853A CN 111732120 A CN111732120 A CN 111732120A
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- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 title claims abstract description 209
- 229910001961 silver nitrate Inorganic materials 0.000 title claims abstract description 103
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 49
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 43
- 229910052709 silver Inorganic materials 0.000 claims abstract description 42
- 239000004332 silver Substances 0.000 claims abstract description 42
- 239000007788 liquid Substances 0.000 claims abstract description 37
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000001704 evaporation Methods 0.000 claims abstract description 28
- 230000008020 evaporation Effects 0.000 claims abstract description 26
- 238000000926 separation method Methods 0.000 claims abstract description 25
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000012535 impurity Substances 0.000 claims abstract description 24
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 24
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000000967 suction filtration Methods 0.000 claims abstract description 16
- 238000001035 drying Methods 0.000 claims abstract description 13
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 10
- 238000004806 packaging method and process Methods 0.000 claims abstract description 8
- 238000002425 crystallisation Methods 0.000 claims abstract description 7
- 230000008025 crystallization Effects 0.000 claims abstract description 7
- 239000002912 waste gas Substances 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 16
- 238000001914 filtration Methods 0.000 claims description 15
- 238000010438 heat treatment Methods 0.000 claims description 11
- 239000000047 product Substances 0.000 claims description 11
- 239000012498 ultrapure water Substances 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- 238000006386 neutralization reaction Methods 0.000 claims description 9
- 238000005406 washing Methods 0.000 claims description 8
- 239000003513 alkali Substances 0.000 claims description 7
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 7
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 7
- 238000004140 cleaning Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 5
- 239000004202 carbamide Substances 0.000 claims description 5
- 238000004090 dissolution Methods 0.000 claims description 5
- -1 polytetrafluoroethylene Polymers 0.000 claims description 5
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 5
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 5
- 239000011148 porous material Substances 0.000 claims description 4
- 239000002250 absorbent Substances 0.000 claims description 3
- 230000002745 absorbent Effects 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 2
- 238000011085 pressure filtration Methods 0.000 claims description 2
- 238000004064 recycling Methods 0.000 abstract description 6
- 239000013078 crystal Substances 0.000 abstract description 5
- 230000009467 reduction Effects 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 19
- 238000010521 absorption reaction Methods 0.000 description 11
- 238000000746 purification Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000004506 ultrasonic cleaning Methods 0.000 description 4
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000003828 vacuum filtration Methods 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003916 acid precipitation Methods 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010170 biological method Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G5/00—Compounds of silver
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/003—Filters in combination with devices for the removal of liquids
- B01D36/006—Purge means
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
- C01B21/38—Nitric acid
- C01B21/40—Preparation by absorption of oxides of nitrogen
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention discloses an environment-friendly efficient production method of high-purity silver nitrate, which comprises the steps of firstly reacting silver ingots with nitric acid to obtain a silver nitrate solution, then purifying the silver nitrate solution, and then sequentially carrying out reduced-pressure efficient evaporation, efficient crystallization, solid-liquid separation, drying, crushing and packaging, wherein 1150-850 kg of silver ingots are subjected to 22-22.5 hours from the time when the silver ingots enter a production line to obtain 1150-1210 kg of high-purity silver nitrate crystal finished products; according to the method, nitric oxide is changed into nitric acid for recycling by absorbing hydrogen peroxide, the impurity removing agent is subjected to impurity removal and then is filtered by combining a negative pressure filter element and a positive pressure filter element, and after high-efficiency pressure reduction evaporation, the solid-liquid high-efficiency separation of silver nitrate is realized by using a suction filtration mode combining a pneumatic diaphragm pump and vacuum negative pressure.
Description
Technical Field
The invention relates to a production method of silver nitrate, in particular to an environment-friendly high-efficiency production method of high-purity silver nitrate.
Background
Silver nitrate is used as a silver chemical product, is a production raw material and a foundation of other silver high-value-added products, and has wide application in the fields of mirror making, medicine, electroplating, superfine silver powder and the like. With the improvement of the product quality requirements of downstream industries, silver nitrate gradually develops towards high purification.
At present, the main method for preparing high-purity silver nitrate is a reaction process of adding nitric acid to dissolve silver, and then silver nitrate crystals are obtained through processes of impurity removal, filtration, evaporation, concentration, crystallization, centrifugation, drying, packaging and the like. During the reaction process of adding nitric acid to dissolve silver, a large amount of nitrogen oxide waste gas (NOx) is generated, and the main reaction is as follows:
2HNO3(concentrated) + Ag = AgNO3+H2O+NO2↑
4HNO3(diluted) +3Ag =3AgNO3+2H2O+NO↑。
With NO and NO2The main nitrogen oxide is an important reason for forming photochemical smog and acid rain, and poses great threat to human health and ecological environment, the common industrial treatment methods include reduction method, liquid absorption method, biological method, adsorption method and the like, from the aspects of investment and operation cost, environmental protection, absorption efficiency, long-term stability and the like, the liquid absorption method is most commonly applied in actual production at present, different absorption agents adopted by different absorption principles have different actual effects, and how to select the absorption agents is a difficult problem facing a plurality of enterprises.
In order to obtain high-purity silver nitrate, the silver nitrate solution needs to be purified and decontaminated to remove some solid impurities and Cu2+、Fe3+And the like metal impurity ions. In principle, solid impurities are removed by filtration, and impurity removing agents or metal impurity ions are removed by high-temperature impurity removal, so that the silver nitrate product meets the high-purity requirement. At present, most of production and preparation processes are low in purification and impurity removal efficiency.
Aiming at the evaporation and concentration process of the silver nitrate solution, the evaporation pressure and temperature have great influence on the evaporation efficiency, and the proper pressure and temperature range is found, so that the efficiency of the evaporation and concentration process is facilitated, and the silver utilization rate of the evaporation process is reduced.
The solid-liquid mixture after the silver nitrate is fully crystallized is usually centrifugally dewatered by a centrifugal machine, the process efficiency is low, and the centrifugal machine running at a high speed has certain potential safety hazard.
In view of the problems in the prior art, it is necessary to design an environment-friendly and efficient method for preparing high-purity silver nitrate.
Disclosure of Invention
The invention aims to solve the technical problems of low efficiency, outstanding environmental protection problems, high cost, unstable quality and the like in the existing industrial production of high-purity silver nitrate, and provides an environment-friendly and high-efficiency production method of high-purity silver nitrate.
The technical scheme adopted by the invention for solving the technical problems is as follows: an environment-friendly and efficient production method of high-purity silver nitrate comprises the following steps
a) Reacting silver ingot with nitric acid to obtain silver nitrate solution
a1) Taking 800-850 kg of national standard No. 1 silver ingots as a batch, and removing stains on the surfaces of the silver ingots through a customized ultrasonic cleaning and airing system, high-purity water cleaning, acid liquor cleaning with the concentration of 3-5%, alkali liquor cleaning with the concentration of 3-5% and other processes in sequence;
a2) putting the cleaned and dried silver ingot into a silver dissolution reaction kettle, adding 60-80L of high-purity water, starting an automatic steam heating system, proportionally and gradually adding 565-610L of analytically pure nitric acid with the concentration of 65-68% at a constant speed, controlling the temperature to be within the range of 85-110 ℃ and heating to react to obtain a silver nitrate solution;
a3) hydrogen peroxide with a certain concentration range is added at the front end of the nitrogen oxide waste gas treatment system to absorb nitrogen oxide generated in the reaction process of silver ingots and analytically pure nitric acid, and absorption liquid (nitric acid) is recycled until the reaction is finished; urea and sodium hydroxide absorbent are added at the rear end of the waste gas treatment system for further absorption, so that the NOx emission concentration is always less than 150ppm, and the emission can reach the standard stably for a long time;
b) purifying silver nitrate solution
b1) Transferring the silver nitrate solution into an impurity removal kettle in vacuum, heating to 80-85 ℃, keeping, adding an impurity removal agent, stirring for 1-1.5 h, standing for 0.5-1 h, performing suction filtration to a silicon carbide filter, performing negative pressure filtration, and transferring the filtrate to a neutralization tank;
b2) adding a proper amount of superior pure nitric acid, and adjusting the pH value of the silver nitrate solution in the neutralization tank to 1.0-2.0;
b3) pumping the silver nitrate solution with the adjusted pH value through a pneumatic diaphragm pump, and filtering the silver nitrate solution to a polytetrafluoroethylene filter for filtration;
c) reduced pressure high efficiency evaporation
The silver nitrate solution after positive pressure and negative pressure combined filtration treatment enters an evaporation tank for reduced pressure evaporation, and evaporation is completed within 2.2-2.5 h;
d) high efficiency crystallization
When the high-efficiency evaporation is finished, transferring the silver nitrate solid-liquid mixture into a crystallizing tank filled with chilled water to complete cooling crystallization of the silver nitrate within 2 hours;
e) solid-liquid separation
Feeding the completely crystallized silver nitrate solid-liquid mixture into a solid-liquid separation tank, performing positive pressure suction filtration and negative pressure suction filtration by using a pneumatic diaphragm pump, realizing solid-liquid separation for 2-2.2 hours, and preparing the obtained silver nitrate solid for the next drying procedure;
f) drying
Putting the silver nitrate solid subjected to solid-liquid separation into an oven, and drying at 94-98 ℃ for 8-9 h to obtain a dried silver nitrate crystal;
g) broken package
And crushing the dried silver nitrate solid by a crusher, and then packaging the silver nitrate solid in automatic packaging equipment to obtain finished silver nitrate. And obtaining 1150-1210 kg of high-purity silver nitrate crystal finished product after 800-850 kg of silver ingots enter the production line for 22-22.5 hours, wherein the detection result shows that the finished product silver nitrate meets the high-grade purity standard in GB/T670-2007 chemical reagent silver nitrate.
In the environment-friendly and efficient production method of high-purity silver nitrate, the diameter of the filtration pore of the silicon carbide filter in the step b 1) is less than or equal to 1 mu m; the diameter of the filtration pore of the polytetrafluoroethylene filter in the step b 3) is less than or equal to 0.45 μm.
The environment-friendly and efficient production method of the high-purity silver nitrate is characterized in that the evaporation and concentration in the step c) are carried out at negative pressure of-70 to-90 KPa and at the temperature of 70-90 ℃.
The environment-friendly and efficient production method of high-purity silver nitrate comprises the step e) that the solid-liquid separation tank consists of a stainless steel filter screen, a pneumatic diaphragm pump and a-80 to-90 KPa vacuum system.
The invention has the beneficial effects that:
most of nitrogen oxide waste gas generated in the reaction process of silver ingots and nitric acid is converted into nitric acid by hydrogen peroxide for recycling, and a small amount of nitrogen oxide which is not absorbed is absorbed by alkali liquor and urea at the rear end of a waste gas system, so that the recycling of the nitric acid is realized, the discharge amount of waste gas and waste water is reduced, the treatment cost is reduced, and the method is more environment-friendly; in the filtering process after impurity removal of the silver nitrate solution, a filtering method of effectively combining negative pressure (less than or equal to 1 mu m) and positive pressure (less than or equal to 0.45 mu m filter element) is adopted, so that the filtering efficiency and the filtering quality are improved, and the product purity is higher; in the process of evaporating and concentrating the silver nitrate solution, negative pressure of 70-90 KPa and reduced pressure evaporation at the temperature of 70-90 ℃ are adopted, the efficiency of evaporating and concentrating the silver nitrate solution is improved, the effective utilization rate of silver is ensured (the total silver amount taken away by water vapor in the evaporation process is less than or equal to 1 thousandth), a mode of combining a pneumatic diaphragm pump and vacuum suction filtration of 80-90 KPa is adopted in the solid-liquid separation process of the fully crystallized silver nitrate, the high-efficiency separation of solid and liquid is realized, and the process is more efficient.
According to the production and preparation process of the silver nitrate, 1150-1210 kg of high-purity silver nitrate crystal finished products can be obtained within 24 hours from the beginning of feeding of 800-850 kg of silver ingots into a production link, so that compared with the preparation process in the prior art, the production and preparation method of the high-purity silver nitrate has the characteristics of environmental protection, high efficiency, low cost and high quality.
Detailed Description
The invention mainly focuses on the reutilization of nitric acid in the reaction process, a special purification process and high-efficiency solid-liquid separation.
The silver dissolution process is as follows.
800-850 kg of national standard No. 1 silver ingots are taken as a batch, and various stains shown by the silver ingots are washed off through a customized ultrasonic cleaning and drying system and processes of high-purity water washing, 3-5% acid washing, 3-5% alkali liquor and the like.
Putting the cleaned and dried silver ingot into a silver dissolving reaction kettle, adding 60-80L of high-purity water, starting an automatic steam heating system, adding 65-68% of analytically pure nitric acid at a constant speed in stages according to a proportion, controlling the temperature within the range of 85-110 ℃, and reacting to obtain a silver nitrate solution.
Hydrogen peroxide with a certain concentration range is added into a pretreatment part of a nitrogen oxide waste gas system to absorb nitrogen oxide generated in the reaction process of silver ingots and nitric acid, and absorption liquid is recycled. And sodium hydroxide and a urea absorbent are added at the rear end of the waste gas system to further absorb the pretreated nitric oxide so as to ensure that the waste gas is fully absorbed and discharged up to the standard.
The silver dissolving process of the invention adopts the introduction of hydrogen peroxide with a certain concentration range to convert most of the nitrogen oxide waste gas into nitric acid for recycling, and a small amount of nitrogen oxide which is not absorbed is absorbed by alkali liquor and urea at the rear end of a waste gas system, thereby realizing the recycling of the nitric acid, reducing the discharge amount of waste gas and waste water and simultaneously reducing the treatment cost. In the existing large-scale silver dissolving process, nitrogen oxide waste gas is converted into nitrogen to be discharged or adsorbed by an adsorbent, so that the treatment difficulty is high, the cost is high, the discharge is easy to reach the standard, a large amount of waste water, waste solids and the like are generated, and the cost is increased.
The specific purification process is as follows.
Transferring the silver nitrate solution into an impurity removal kettle in vacuum, heating to 80-85 ℃, adding an impurity removal agent, stirring for 1-1.5 h, standing for about 0.5-1.5 h, performing vacuum filtration to a1 mu m silicon carbide filter by using negative pressure, and transferring the solution into a neutralization tank.
Adding a proper amount of superior pure nitric acid, and adjusting the pH value of the silver nitrate solution in the neutralization tank to 1.0-2.0. The silver nitrate solution with the adjusted pH value is pumped by a pneumatic diaphragm pump and is filtered under positive pressure by a polytetrafluoroethylene filter element (less than or equal to 0.45 mu m).
The special purification process can ensure that the impurity content of the silver nitrate solution is in a lower level, and simultaneously improves the production efficiency. The prior purification technology adopts a mode of impurity removal by an impurity removing agent and secondary crystallization, and has the disadvantages of time and labor consumption, low production efficiency and high production cost.
The efficient solid-liquid separation is as follows.
And (3) feeding the completely crystallized silver nitrate solid-liquid mixture into a solid-liquid separation tank, combining a pneumatic diaphragm pump with vacuum filtration of 80-90 Kpa to realize high-efficiency solid-liquid separation of the silver nitrate, and directly feeding the separated product into an oven for drying.
The high-efficiency solid-liquid separation technology of the invention combines vacuum filtration and pneumatic diaphragm pump filtration processes, and can realize high-efficiency solid-liquid separation. The existing mode is centrifugal drying of a centrifugal machine, needs a small amount of centrifugal drying for multiple times, and has the disadvantages of large labor capacity, low production efficiency and certain potential safety hazard.
The invention is further illustrated by the following examples, without limiting the scope of protection to these examples.
Example 1
Taking 800kg of national standard No. 1 silver ingots, and carrying out ultrasonic cleaning and air drying on the silver ingots by using a high-purity water washing process, a 3-5% acid washing process, a 3-5% alkali liquor washing process and the like to wash off stains on the surfaces of the silver ingots. Putting the silver into a silver dissolution reaction kettle, adding high-purity water and 65-68% of analytically pure nitric acid, heating, and reacting to obtain a silver nitrate solution. Hydrogen peroxide with a certain concentration range is added into a pretreatment part of a waste gas system to absorb nitrogen oxides, the absorption liquid is recycled, and the concentration of NOx in the exhaust stack is always less than 125ppm, so that the exhaust stack meets the emission standard. Transferring the silver nitrate solution obtained by the reaction into an impurity removal kettle in vacuum, heating to 80-85 ℃, adding an impurity removal agent, standing for 1h, performing suction filtration under negative pressure until the silicon carbide with the diameter of 1 mu m is filtered, and transferring the solution to a neutralization tank. And adjusting the pH value of the silver nitrate solution in the neutralization tank to 1.0-2.0, performing suction filtration (filter element less than or equal to 0.45 mu m) through a pneumatic diaphragm pump until the silver nitrate solution is evaporated in the evaporation tank under reduced pressure, and performing evaporation concentration on the silver nitrate solution by adopting negative pressure of-70 to-90 KPa and setting the temperature of 70-90 ℃ in the whole process for 2.5 hours. Transferring the material into a crystallizing tank, and introducing chilled water into the crystallizing tank to crystallize the silver nitrate for 2 hours. The materials enter a solid-liquid separation tank, and are subjected to negative pressure suction filtration of-80 to-90 KPa and positive pressure suction filtration of a pneumatic diaphragm pump, so that solid-liquid separation is realized within 2 hours. And (3) drying the silver nitrate solid in an oven, crushing the silver nitrate solid in a crusher, packaging the silver nitrate solid for 22 hours to obtain 1150kg of finished silver nitrate, wherein a detection result shows that the finished silver nitrate meets the high-grade pure standard in GB/T670-2007 chemical reagent silver nitrate.
Compared with the prior art: hydrogen peroxide is added into a waste gas pretreatment system, so that nitrogen oxide waste gas generated in the silver dissolving process is converted into nitric acid for recycling, and the environment-friendly and low-cost production process is realized; the silver nitrate solution is subjected to a special purification process, so that the high purity requirement and high efficiency of a silver nitrate product are ensured; the evaporation process selects proper temperature and pressure, thereby ensuring high evaporation efficiency; the solid-liquid separation process utilizes a stainless steel filter screen, and adopts a mode of combining a pneumatic diaphragm pump and vacuum negative pressure, so that the high efficiency of the solid-liquid separation is ensured.
Example 2
850kg of national standard No. 1 silver ingot is taken to be subjected to an ultrasonic cleaning and airing system, and stains on the surface of the silver ingot are washed away through the processes of high-purity water washing, 3-5% acid washing, 3-5% alkali liquor and the like. Putting the silver into a silver dissolution reaction kettle, adding high-purity water and 65-68% of analytically pure nitric acid, heating, and reacting to obtain a silver nitrate solution. Hydrogen peroxide with a certain concentration range is added into a pretreatment part of the waste gas system to absorb nitrogen oxides, the absorption liquid is recycled, and the concentration of NOx in the exhaust stack is always less than 133ppm, so that the exhaust stack meets the emission standard. Transferring the silver nitrate solution obtained by the reaction into an impurity removal kettle in vacuum, heating to 80-85 ℃, adding an impurity removal agent, standing for 0.5h, performing suction filtration under negative pressure until the silicon carbide solution with the diameter of 1 mu m is filtered, and transferring the filtered solution into a neutralization tank. And adjusting the pH value of the silver nitrate solution in the neutralization tank to 1.0-2.0, performing suction filtration (filter element less than or equal to 0.45 mu m) through a pneumatic diaphragm pump until the silver nitrate solution is evaporated in the evaporation tank under reduced pressure, and performing evaporation concentration on the silver nitrate solution by adopting negative pressure of-70 to-90 KPa and setting the temperature of 80-90 ℃ in the whole process for 2.2 h. Transferring the material into a crystallizing tank, and introducing chilled water into the crystallizing tank to crystallize the silver nitrate for 2 hours. The materials enter a solid-liquid separation tank, and are subjected to negative pressure suction filtration of-80 to-90 KPa and suction filtration of a pneumatic diaphragm pump, so that solid-liquid separation is realized within 2.2 hours. And (3) drying the silver nitrate solid in an oven, crushing the silver nitrate solid in a crusher, packaging the silver nitrate solid, and obtaining 1210kg of finished silver nitrate after 22.5h, wherein a detection result shows that the finished silver nitrate meets the high-grade pure standard in GB/T670-2007 chemical reagent silver nitrate.
The above-described embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments may be applied, and it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the inventive concept of the present invention, and these embodiments are within the scope of the present invention.
Claims (4)
1. An environment-friendly and efficient production method of high-purity silver nitrate is characterized by comprising the following steps: comprises the steps of
a) Preparation of silver nitrate solution
a1) Taking 800-850 kg of silver ingots, ultrasonically cleaning and airing, and then sequentially washing with high-purity water, cleaning with acid liquor with the concentration of 3-5% and cleaning with alkali liquor with the concentration of 3-5%, so as to remove stains on the surfaces of the silver ingots;
a2) putting the dried silver ingot into a silver dissolution reaction kettle, adding 60-80L of high-purity water, adding 565-610L of analytically pure nitric acid with the concentration of 65-68%, and heating at the temperature of 85-110 ℃ to obtain a silver nitrate solution;
a3) adding hydrogen peroxide to absorb nitrogen oxides generated in the reaction process of silver ingots and analytically pure nitric acid, and then adding sodium hydroxide and urea as absorbents to ensure that waste gas is fully absorbed and discharged after reaching the standard;
b) purifying silver nitrate solution
b1) Transferring the silver nitrate solution into an impurity removal kettle in vacuum, heating to 80-85 ℃, adding an impurity removal agent, stirring for 1-1.5 h, standing for 0.5-1 h, performing suction filtration to a silicon carbide filter, performing negative pressure filtration, and transferring the filtrate to a neutralization tank;
b2) adding pure nitric acid, and adjusting the pH value of a silver nitrate solution in the tank to 1.0-2.0;
b3) filtering the silver nitrate solution to a polytetrafluoroethylene filter by a pneumatic diaphragm pump;
c) reduced pressure high efficiency evaporation
The silver nitrate solution enters an evaporation tank to finish reduced pressure evaporation within 2.2-2.5 h;
d) high efficiency crystallization
Transferring the silver nitrate solid-liquid mixture into a crystallizing tank filled with chilled water, and completing the crystallization of the silver nitrate within 2 hours;
e) solid-liquid separation
Feeding the completely crystallized silver nitrate solid-liquid mixture into a solid-liquid separation tank, and performing positive pressure suction filtration and negative pressure suction filtration by using a pneumatic diaphragm pump to realize solid-liquid separation within 2-2.2 h;
f) drying
Putting the silver nitrate solid into an oven, and drying at 94-98 ℃ for 8-9 h;
g) broken package
And crushing the silver nitrate solid by a crusher, and then packaging the silver nitrate solid in automatic packaging equipment to obtain 1150-1210 kg of high-purity silver nitrate finished product.
2. The method for environment-friendly and high-efficiency production of high-purity silver nitrate according to claim 1, characterized in that the diameter of the filtration pore of the silicon carbide filter in the step b 1) is less than or equal to 1 μm; the diameter of the filtration pore of the polytetrafluoroethylene filter in the step b 3) is less than or equal to 0.45 μm.
3. The method for environment-friendly and high-efficiency production of high-purity silver nitrate according to claim 1, wherein the evaporation concentration in the step c) is performed at a negative pressure of-70 to-90 KPa and a temperature of 70 to 90 ℃.
4. The method for environment-friendly and high-efficiency production of high-purity silver nitrate according to claim 1, characterized in that the solid-liquid separation tank in the step e) consists of a stainless steel filter screen, a pneumatic diaphragm pump and a vacuum system of-80 to-90 KPa.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113443746A (en) * | 2021-07-15 | 2021-09-28 | 北京津工海水科技有限公司 | Waste liquid treatment reaction tower for preparing silver paste of circuit board and preparation treatment process |
| CN115072764A (en) * | 2022-07-04 | 2022-09-20 | 广东先导稀材股份有限公司 | Preparation method of metal nitrate |
| CN115108577A (en) * | 2022-06-28 | 2022-09-27 | 桐柏泓鑫新材料有限公司 | High-purity silver nitrate low-energy-consumption preparation method and system |
| CN116216767A (en) * | 2023-03-29 | 2023-06-06 | 湖南海利高新技术产业集团有限公司 | Silver nitrate preparation method and device |
| CN116462221A (en) * | 2023-03-24 | 2023-07-21 | 达高工业技术研究院(广州)有限公司 | Production process of high-purity silver nitrate, high-purity silver nitrate and application thereof |
| CN116462221B (en) * | 2023-03-24 | 2024-11-08 | 达高工业技术研究院(广州)有限公司 | Production process of high-purity silver nitrate, high-purity silver nitrate and application thereof |
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| CN113443746A (en) * | 2021-07-15 | 2021-09-28 | 北京津工海水科技有限公司 | Waste liquid treatment reaction tower for preparing silver paste of circuit board and preparation treatment process |
| CN115108577A (en) * | 2022-06-28 | 2022-09-27 | 桐柏泓鑫新材料有限公司 | High-purity silver nitrate low-energy-consumption preparation method and system |
| CN115108577B (en) * | 2022-06-28 | 2024-04-19 | 桐柏泓鑫新材料有限公司 | Low-energy-consumption preparation method and system for high-purity silver nitrate |
| CN115072764A (en) * | 2022-07-04 | 2022-09-20 | 广东先导稀材股份有限公司 | Preparation method of metal nitrate |
| CN116462221A (en) * | 2023-03-24 | 2023-07-21 | 达高工业技术研究院(广州)有限公司 | Production process of high-purity silver nitrate, high-purity silver nitrate and application thereof |
| CN116462221B (en) * | 2023-03-24 | 2024-11-08 | 达高工业技术研究院(广州)有限公司 | Production process of high-purity silver nitrate, high-purity silver nitrate and application thereof |
| CN116216767A (en) * | 2023-03-29 | 2023-06-06 | 湖南海利高新技术产业集团有限公司 | Silver nitrate preparation method and device |
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