CN112210674A - Production process of high-purity gold - Google Patents
Production process of high-purity gold Download PDFInfo
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Abstract
The invention discloses a production process of high-purity gold, which relates to the technical field of metal extraction and comprises the following steps: s1, aqua regia gold dissolving: dissolving crude gold in aqua regia to obtain a solution, removing nitre, and filtering to obtain a crude gold solution; s2, reduction: adding a reducing agent into the crude gold liquid obtained in the step S1, filtering to obtain primary fine gold powder, and washing with pure water to be neutral; s3, acid leaching: soaking the primary fine gold powder obtained in the step S2 in a nitric acid solution, and filtering to obtain pure fine gold powder; s4, gold smelting: and (5) cleaning the pure fine gold powder obtained in the step (S3) by using pure water, drying and then inspecting, and casting a ingot into a high-purity gold product after the inspection is qualified. The invention has the technical effects of high production safety, short process flow period and good controllability.
Description
Technical Field
The invention relates to the technical field of metal extraction, in particular to a production process of high-purity gold.
Background
High purity gold refers to a gold product with a purity of 99.999%, and is marked as Au 99999. The high-purity gold is a gold wire production raw material necessary for semiconductor connection, has good manufacturability, and is easy to process into ultrathin gold foil, micron gold wire and gold powder to be plated on the surfaces of other metals, ceramics and glass. The high-purity gold is welded and forge welded under a certain pressure, can be made into superconductor, organic gold and the like, and can be widely applied to modern high and new technology enterprises of electronic technology, communication technology, aerospace technology, chemical technology, medical technology and the like.
The current high-purity gold production process comprises an electrolytic method, a solvent extraction method, a chemical reduction method and the like. Wherein, the electrolysis method has the defects of long production period, poor operation condition, large gold accumulation and the like; the solution extraction method is to prepare high-purity gold by using extracting agents such as diethyl ether, dibutyl carbitol and the like, but the produced high-purity gold is easy to wrap an organic solvent, so that the gold purity is influenced; in addition, the extractant is extremely easy to volatilize, the production environment is poor, and potential safety hazards exist in the operation process.
Disclosure of Invention
The invention aims to provide a production process of high-purity gold, which has high production safety, short process flow period and good controllability.
The invention is realized by the following technical scheme:
a production process of high-purity gold comprises the following steps:
s1, aqua regia gold dissolving: dissolving crude gold in aqua regia to obtain a solution, removing nitre, and filtering to obtain a crude gold solution;
s2, reduction: adding a reducing agent into the crude gold liquid obtained in the step S1, filtering to obtain primary fine gold powder, and cleaning the primary fine gold powder to be neutral by using pure water;
s3, acid leaching: soaking the primary fine gold powder obtained in the step S2 in a nitric acid solution, and filtering to obtain pure fine gold powder;
s4, gold smelting: and (5) cleaning the pure fine gold powder obtained in the step (S3) by using pure water to be neutral, drying, then inspecting, and casting ingots into high-purity gold products after qualified detection.
By adopting the technical scheme, the aqua regia is a mixture of concentrated hydrochloric acid and concentrated nitric acid according to the volume ratio of 3:1, and is one of a few liquids capable of dissolving gold substances. In the step S1, gold and trace impurity metals such as copper, zinc and iron in the crude gold are converted into complex ions or ions under the action of aqua regia and enter the solution in the gold dissolving process by aqua regia, and silver and lead are precipitated into slag by silver chloride and lead chloride. Besides fast gold dissolving speed, the aqua regia shortens the gold dissolving process period and can also achieve the purpose of primarily removing silver and lead impurities.
After gold is dissolved by aqua regia, nitrate removing agent is added to react with redundant nitric acid in the solution, so that the phenomenon that subsequent gold reduction is incomplete or gold powder is re-dissolved due to the excessive nitric acid is prevented. And in the step S2, before the reducing agent is put into the crude gold liquid, filtering the crude gold liquid subjected to the saltpeter removing process in the step S1, filtering out silver chloride precipitate and other insoluble impurities, reducing the adverse effect of the impurities on the reducing agent in the step S2, and reducing the gold by the reducing agent sufficiently to generate fine gold powder with fine granularity.
In the step S3, the fine gold powder filtered in the step S2 is soaked in a nitric acid solution, the nitric acid has strong oxidizing property, and can oxidize and dissolve part of metal powder impurities reduced by the reducing agent in the step S2, but cannot dissolve the gold powder, so that secondary impurity removal can be performed on the gold powder, and the purity of the gold powder is improved.
And in the step S4, cleaning the pure fine gold powder obtained in the step S3 by pure water, removing nitric acid solution attached to the surface of the pure fine gold powder and impurity compounds in the nitric acid solution, removing impurities for the last time, drying, inspecting, and casting ingots into high-purity gold products after inspection is qualified, wherein the high-purity gold products have higher purity and more stable quality.
In the steps of S1, S2, S3 and S4, a chemical method is adopted for gold dissolving and refining, and impurities are removed for many times in the refining process, so that the process flow period is shortened while the high-purity gold meets the requirement of 99.999 percent of purity, the safety and the controllability in the production process are high, and the high-purity gold is beneficial to high-efficiency and high-quality production of enterprises.
Further setting the following steps: in step S1, the volume of aqua regia used per 1kg of crude gold dissolved is 4L.
Further setting the following steps: in the step S1, urea is used as a nitrate removing agent in the nitrate removing process, and the dosage of the nitrate removing agent is 0.6-0.8 time of the gold dissolving amount.
By adopting the technical scheme, because the aqua regia is formed by mixing concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1, the gold dissolving amount of 1kg is oxidized by corresponding 1L of concentrated nitric acid, and the dosage of the concentrated nitric acid can completely dissolve the crude gold without causing large waste of the concentrated nitric acid. The urea reacts with the excess nitric acid after gold dissolution in step S1 as a nitrate-removing agent to produce nitrogen and carbon dioxide, and the nitric acid is reduced to nitrogen oxide. The urea raw material is easy to obtain and low in price, the self reaction product of the urea raw material and the nitric acid is nitrogen and carbon dioxide, the nitrogen is removed, new impurities are prevented from being introduced into the crude gold liquid, and the product is more environment-friendly. The dosage of the nitrate removing agent is 0.6 to 0.8 time of the gold dissolving amount, so that the nitric acid in the crude gold liquid can be fully removed, the excessive introduction of new impurity elements into the urea is avoided, the urea dosage is saved, and the production cost is reduced.
Further setting the following steps: in the step S1, when the oxidation-reduction potential of the solution reaches 700-900mV, the nitrate removing process is stopped.
By adopting the technical scheme, because urea and nitric acid have redox reaction in the nitrate removing process, the nitric acid serving as an oxidant is continuously reduced, so that the redox potential in the crude gold liquid can be gradually reduced, the redox potential can reflect the proceeding degree of the nitrate removing reaction, and the proceeding degree of the nitrate removing reaction in the crude gold liquid can be monitored by monitoring the redox potential in the crude gold liquid. When the oxidation-reduction potential of the crude gold liquid in the step S1 reaches 700-900mV, the removal of redundant nitric acid in the crude gold liquid tends to be complete, the control of the nitrate removing reaction is more accurate and flexible, the reaction precision is improved, the purification precision is improved, and the production cost is reduced.
Further setting the following steps: in the step of S2, the reducing agent is sodium sulfite, and the using amount of the sodium sulfite is 0.6-0.8 time of the gold dissolving amount.
By adopting the technical scheme, the sodium sulfite has stronger reducibility, and can oxidize gold ions or complex gold ions in the crude gold liquid into simple substances of gold powder. The dosage of the sodium sulfite is 0.6 to 0.8 time of the gold dissolving amount, and the dosage is matched with the gold content in the crude gold liquid, so that not only can the gold ions and the complex gold ions in the crude gold liquid be basically reduced, but also the minimum dosage for achieving the expected effect is achieved, and the production cost is reduced.
Further setting the following steps: in the step S2, the oxidation-reduction potential of the crude gold liquid is controlled at 400-500 mV.
By adopting the technical scheme, after the reducing agent sodium sulfite is put into the crude gold liquid, the oxidation-reduction potential of the crude gold liquid is lower than that in the nitrate removing process because the positively charged metal ions in the crude gold liquid are reduced. In the reduction process, the control of the oxidation-reduction potential is directly related to the reaction sequence of the reducing agent and the metal ions in the crude gold liquid, and the oxidation-reduction potential in the crude gold liquid is controlled to be 400-500mV, so that the sodium sulfite can preferentially reduce the gold ions or complex gold ions, further the metal simple substance impurities generated by the reduction of other metal ions by the reducing agent are reduced, and the reduction efficiency and the quality of the gold powder are improved.
Further setting the following steps: in the step S3, the mass fraction of the nitric acid solution is 40-65%, and the temperature is 70-80 ℃.
By adopting the technical scheme, in the step S3, the hot nitric acid with the mass fraction of 40-65% and the temperature of 70-80 ℃ can oxidize and dissolve a small amount of metal impurities reduced from the sodium sulfite in the step S2, and the hot nitric acid has higher reaction activity compared with cold nitric acid, so that the metal impurities in the gold powder are efficiently removed, and the purity of the gold powder is improved.
Further setting the following steps: in the step S3, the soaking times are 2-4 times, the soaking time is 0.5-1h each time, and the nitric acid solution is replaced by the soaking time each time.
By adopting the technical scheme, when the fine gold powder is soaked by the nitric acid, the concentration of the nitric acid is reduced along with the reaction of the nitric acid and metal impurities in the fine gold powder, and the impurity removal effect in the later soaking period is not as good as that in the earlier stage. Therefore, the fine gold powder is soaked in the new nitric acid solution for many times, so that the impurities in the fine gold powder can react more completely and the impurities can be removed more thoroughly.
Further setting the following steps: in the step S4, the temperature of the clean water is 60-80 ℃.
By adopting the above technical scheme, in step S2, Cl can be adsorbed due to incomplete surface lattice of the fine gold powder generated by reduction-Resulting in fine gold powder surface Cl-The concentration is higher than that of the solution, so that other metal cations in the solution are easily complexed or adsorbed, and impurities in the fine gold powder exceed the standard. The fine gold powder can be washed by hot water to adsorb Cl on the surface of the fine gold powder-Completely washing the gold, and improving the quality of the final high-purity gold.
In conclusion, the beneficial technical effects of the invention are as follows:
(1) gold is dissolved by aqua regia, gold in crude gold and trace impurity metals such as copper, zinc, iron and the like are converted into complex ions or ions under the action of the aqua regia to enter a solution, and silver and lead are precipitated into slag by silver chloride and lead chloride, so that the aqua regia not only accelerates the gold dissolving speed and shortens the gold dissolving process period, but also can realize the preliminary removal of silver impurities;
(2) the urea is utilized to carry out nitrate removal on the aqua regia after gold dissolution, the urea is oxidized into nitrogen and carbon dioxide, the nitric acid is reduced into nitrogen oxide, the urea raw material is easy to obtain and low in price, the self reaction product after the urea reacts with the nitric acid is the nitrogen and the carbon dioxide, the nitrogen is removed, the introduction of new impurities into the crude gold liquid is avoided, and the product is more environment-friendly;
(3) the reaction heavy end point of the nitrate removing process is judged by monitoring the oxidation-reduction potential of the crude gold liquid in the nitrate removing process, the control of the nitrate removing reaction is more accurate and flexible, the reaction precision is improved, the purification precision is improved, and the production cost is reduced; meanwhile, in the reduction process, the oxidation-reduction potential in the crude gold liquid is controlled to be 400-500mV, so that the sodium sulfite can preferentially reduce the gold ions or complex gold ions, further the metal simple substance impurities generated by reducing other metal ions by the reducing agent are reduced, and the reduction efficiency and the quality of the fine gold powder are improved.
Detailed Description
A production process of high-purity gold comprises the following steps:
s1, aqua regia gold dissolving: dissolving crude gold in aqua regia to obtain a solution, removing nitre, and filtering to obtain a crude gold solution;
s2, reduction: adding a reducing agent into the crude gold liquid obtained in the step S1, filtering to obtain primary fine gold powder, and cleaning the primary fine gold powder to be neutral by using pure water;
s3, acid leaching: soaking the primary fine gold powder obtained in the step S2 in a nitric acid solution, and filtering to obtain pure fine gold powder;
s4, gold smelting: and (5) cleaning the pure fine gold powder obtained in the step (S3) to be neutral by using pure water, drying, then inspecting, and casting a ingot into a high-purity gold product after the inspection is qualified.
The present invention will be described in further detail with reference to specific examples.
Example 1, a production process of high-purity gold, comprising the following specific production steps:
s1, aqua regia gold dissolving: 1kg of crude gold (containing 99.000 percent of gold) is placed in a reactor, 4L of aqua regia is added into the reactor, and the aqua regia is prepared by concentrated hydrochloric acid (mass fraction of 37 percent) and concentrated nitric acid (mass fraction of 68 percent) in a volume ratio of 3: 1. After the gold dissolving reaction is basically finished and the temperature of the solution is reduced to room temperature, adding urea as a nitrate removing agent into the reactor at a constant speed of 100g/min for removing nitrate, simultaneously monitoring the oxidation-reduction potential in the solution in real time, stopping adding urea when the oxidation-reduction potential E1 in the solution reaches 700mV, stopping adding nitrate, and controlling the total amount of added urea to be 0.60kg in the nitrate removing process. And after the nitrate removing process is stopped, filtering the solution by using a high-precision filter to obtain a crude gold liquid.
S2, reduction: and (4) placing the crude gold liquid obtained in the step S1 into a new reactor, and adding a reducing agent sodium sulfite into the reactor at a constant speed of 100g/min while stirring, wherein the adding total amount of the sodium sulfite is 0.60 kg. In order to better control the preferential occurrence of the oxidation-reduction reaction on the gold ions and the complex gold ions in the solution, the oxidation-reduction potential E2 in the solution is always controlled at 400mV by adjusting the pH value of the solution, the reaction temperature is controlled at 50-60 ℃, and the reduction reaction time t is 50 min. And after the reduction reaction is finished, filtering the solution by using a high-precision filter to obtain primary fine gold powder, and cleaning the primary fine gold powder by using pure water until the primary fine gold powder is neutral.
S3, acid leaching: and (2) placing the primary fine gold powder obtained in the step S2 into a new reactor, adding an excessive nitric acid solution with the mass fraction of 40-65% and the temperature of 70-80 ℃ into the reactor, standing and soaking for 2 times, replacing the fresh nitric acid solution with the mass fraction of 40-65% and the temperature of 70-80 ℃ each time, and filtering to obtain pure fine gold powder, wherein the soaking time is 0.5 h.
S4, washing the pure fine gold powder obtained in the step S3 for 3 times by using hot pure water at the temperature of 60-80 ℃ until the pure fine gold powder is neutral, drying the pure fine gold powder, then checking the purity, and casting the pure fine gold powder into a high-purity gold product after the detection is qualified, wherein the detection result is shown in Table 1.
Example 2: the difference between the embodiment and the embodiment 1 is that in the step S1, when the oxidation-reduction potential E1 in the solution reaches 750mV, the feeding of urea is stopped, the nitrate removal is stopped, and the total amount of urea added in the nitrate removal process is 0.65 kg. In step S2, the oxidation-reduction potential E2 was constantly controlled at 425mV, the amount of sodium sulfite added as a reducing agent was 0.65kg, and the reduction time t was 55 min. In step S3, the number of times n of immersing the fine gold powder in the nitric acid solution is 3, and the time of immersing in nitric acid is 0.65 hour each time.
Example 3: the difference between the embodiment and the embodiment 1 is that in the step S1, when the oxidation-reduction potential E1 in the solution reaches 800mV, the feeding of urea is stopped, the nitrate removal is stopped, and the total amount of urea added in the nitrate removal process is 0.70 kg. In step S2, the oxidation-reduction potential E2 is always controlled at 450mV, the total amount of sodium sulfite added as a reducing agent is 0.70kg, and the reduction time t is 60 min. In step S3, the number of times n of immersing the fine gold powder in the nitric acid solution is 4, and the time of immersing in nitric acid is 0.75 hour each time.
Example 4: the difference between the embodiment and the embodiment 1 is that in the step S1, when the oxidation-reduction potential E1 in the solution reaches 850mV, the feeding of urea is stopped, the nitrate removal is stopped, and the total amount of urea added in the nitrate removal process is 0.75 kg. In step S2, the oxidation-reduction potential E2 is always controlled at 475mV, the total amount of sodium sulfite added as a reducing agent is 0.75kg, and the reduction time t is 65 min. In step S3, the number of times n of immersing the fine gold powder in the nitric acid solution is 3, and the time of immersing in nitric acid is 0.85 hour each time.
Example 5: the difference between the embodiment and the embodiment 1 is that in the step S1, when the oxidation-reduction potential E1 in the solution reaches 900mV, the feeding of urea is stopped, the nitrate removal is stopped, and the total amount of urea added in the nitrate removal process is 0.80 kg. In step S2, the oxidation-reduction potential E2 is always controlled at 500mV, the total amount of sodium sulfite added as a reducing agent is 0.80kg, and the reduction time t is 70 min. In step S3, the number of times n of immersing the fine gold powder in the nitric acid solution is 4, and the time of immersing in nitric acid is 1.0 hour each time.
Comparative example 1: the comparative example differs from example 1 in that in step S1, when the oxidation-reduction potential E1 in the solution reaches 300-500mV, the addition of urea is stopped and the nitrate removal is stopped.
Comparative example 2: the comparative example differs from example 1 in that in step S1, when the oxidation-reduction potential E1 in the solution reaches 1000-1200mV, the addition of urea is stopped and the nitrate removal is stopped.
Comparative example 3: the present comparative example is different from example 2 in that the oxidation-reduction potential E2 of the crude gold liquid was always controlled to be between 200mV and 300mV in step S2.
Comparative example 4: the present comparative example is different from example 2 in that the oxidation-reduction potential E2 of the crude gold liquid was always controlled to be between 600 and 700mV in step S2.
Comparative example 5: this comparative example differs from example 3 in that the reduction time t in step S2 was 30 min.
Comparative example 6: this comparative example differs from example 3 in that the reduction time t in step S2 was 90 min.
Comparative example 7: the present comparative example is different from example 4 in that the number of times n of immersion of the fine gold powder in the nitric acid solution in step S3 is 1.
Comparative example 8: the present comparative example is different from example 4 in that the number of times n of immersion of the fine gold powder in the nitric acid solution in step S3 is 5.
And (3) impurity determination:
the high purity gold products obtained in examples 1 to 5 and comparative examples 1 to 8 were subjected to impurity element analysis using the method and standard shown in "chemical analysis of high purity gold ICP-MS method (manuscript of opinion)", and the analysis results are shown in tables 1 and 2, respectively. (in the table "-" indicates that the element is not present).
Table 1 examples 1-5 table of analysis data of impurity elements
TABLE 2 table of analysis data of comparative examples 1 to 8 for impurity elements
Data analysis
As can be seen from the analysis of Table 1, the main impurities of the crude gold (gold content of 99% or more) used in examples 1 to 5 and comparative examples 1 to 8 were Ag, Al, Mg, As, Se, Zn and Na, and the high purity gold products of examples 1 to 5 all reached the purity specified in the chemical analysis of high purity gold method ICP-MS (research and review), and the recovery rate of gold was maintained at 99.95% or more, indicating that the high purity gold of high quality and high yield could be obtained by purification using the production process of the present invention.
As can be seen from the analysis of table 2, in comparative example 1, the purity and the recovery yield of the high-purity gold are both similar to those of example 1, and the purity reaches the standard, which indicates that when the oxidation-reduction potential E1 of the solution is lower than 700mV in step S1, the nitrate removal is thorough, and there is no influence on the subsequent oxidation-reduction reaction, so that the purity and the yield of the high-purity gold product are not influenced, but more nitrate removal agent is consumed, and the industrial production is not cost-effective. In contrast, in comparative example 2, when the oxidation-reduction potential E1 of the solution was higher than 900mV, the purity of the high purity gold product was similar to that of example 1, but the recovery yield was much lower than that of example 1, which indicates that nitrate removal did not proceed completely in step S1, nitrate ions remained in the crude gold solution, and nitrate ions consumed the reducing agent sodium sulfite in step S2, resulting in a decrease in the yield of gold reduced by sodium sulfite, and finally a decrease in the recovery yield of gold from the high purity gold product.
Analysis table 2 shows that in comparative example 3, when the redox potential in the crude gold solution is lower than 400mV, the recovery amount of the high-purity gold product is at a higher level, but the contents of Se, As and Zn impurities in the high-purity gold product are all greatly increased, which indicates that when the redox potential in the crude gold solution is too low, the order of redox reaction between the reducing agent sodium sulfite and the metal ions in the crude gold solution is changed, and the ions of Se, As and Zn with stronger oxidizability are separated first instead of gold, so that the content of the impurities in the high-purity gold product is increased. In comparative example 4, the purity of the high purity gold is similar to that of example 2, and the purity reaches the standard, but the recovery yield of the high purity gold product is greatly reduced compared with that of example 2, which indicates that in step S2, when the oxidation-reduction potential in the crude gold solution is higher than 500mV, the gold oxidation-reduction in the crude gold solution is incomplete, and part of the gold ions or complex gold ions are not reduced into simple substances, resulting in a large reduction in the recovery yield of the high purity gold.
Analyzing table 2, when the reduction time (30min) in step S2 in comparative example 5 is too short, the purity of the high-purity gold product in comparative example 5 is similar to that in example 3, and the purity reaches the standard, but the recovery yield of the high-purity gold is greatly reduced compared with example 3, which indicates that the reduction time is too short, the reducing agent does not sufficiently react with the gold ions or complex gold ions in the crude gold solution, and a part of gold is not reduced, resulting in a reduction in the recovery yield of the high-purity gold product. In comparative example 6 corresponding to comparative example 5, when the reduction time (90min) is too long, the purity and the recovery yield of the high-purity gold product are not greatly affected, but the whole production cycle is prolonged, which is not favorable for the high-efficiency production and income of enterprises.
Analysis table 2 shows that the recovery amount of the high purity gold product in comparative example 7 is at a high level, but the contents of Se, As and Zn in the high purity gold product are all greatly increased, which indicates that in the case of soaking with hot nitric acid only once, the reduced impurities of Se, As and Zn in the fine gold powder are not completely dissolved by the reaction of the nitric acid solution, resulting in more impurity residues than in example 4. In comparative example 8 corresponding to comparative example 7, the number of soaking times of the fine gold powder in the nitric acid solution is 5, the recovery amount and the purity of the high-purity gold product both reach the standard, but the acid leaching times are increased, namely the treatment procedures are increased, the treatment period is prolonged, and the method is not beneficial to high-efficiency production of enterprises.
The implementation principle and the beneficial effects of the embodiment are as follows: gold is dissolved by aqua regia, gold in crude gold and trace impurity metals such as copper, lead, zinc, iron and the like are converted into complex ions or ions under the action of the aqua regia and enter a solution, and silver is precipitated into slag by silver chloride, so that the aqua regia can accelerate the gold dissolving speed, shorten the gold dissolving process period and also realize the preliminary removal of silver impurities. The reaction end point of the nitrate removing process is judged by monitoring the oxidation-reduction potential of the crude gold liquid in the nitrate removing process, the control of the nitrate removing reaction is more accurate and flexible, the reaction precision is improved, the purification precision is improved, and the production cost is reduced; meanwhile, in the reduction process, the oxidation-reduction potential in the crude gold liquid is controlled to be 400-500mV, so that the sodium sulfite can preferentially reduce the gold ions or complex gold ions, further the metal simple substance impurities generated by reducing other metal ions by the reducing agent are reduced, and the reduction efficiency and the quality of the fine gold powder are improved.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.
Claims (9)
1. The production process of high-purity gold is characterized by comprising the following steps of:
s1, aqua regia gold dissolving: dissolving crude gold in aqua regia to obtain a solution, removing nitre, and filtering to obtain a crude gold solution;
s2, reduction: adding a reducing agent into the crude gold liquid obtained in the step S1, filtering to obtain primary fine gold powder, and cleaning the primary fine gold powder to be neutral by using pure water;
s3, acid leaching: soaking the primary fine gold powder obtained in the step S2 in a nitric acid solution, and filtering to obtain pure fine gold powder;
s4, gold smelting: and (5) cleaning the pure fine gold powder obtained in the step (S3) to be neutral by using pure water, drying, then inspecting, and casting a ingot into a high-purity gold product after the inspection is qualified.
2. The process for producing high purity gold according to claim 1, characterized in that: in step S1, the volume of aqua regia used per 1kg of crude gold dissolved is 4L.
3. The process for producing high purity gold according to claim 1 or 2, characterized in that: in the step S1, urea is used as a nitrate removing agent in the nitrate removing process, and the dosage of the nitrate removing agent is 0.6-0.8 time of the gold dissolving amount.
4. The process for producing high purity gold according to claim 1, characterized in that: in the step S1, when the oxidation-reduction potential of the solution reaches 700-900mV, the nitrate removing process is stopped.
5. The production process of high-purity gold according to claim 1 or 4, characterized in that: in the step of S2, the reducing agent is sodium sulfite, and the using amount of the sodium sulfite is 0.6-0.8 time of the gold dissolving amount.
6. The process for producing high-purity gold according to claim 5, wherein: in the step S2, the oxidation-reduction potential of the crude gold liquid is controlled at 400-500 mV.
7. The process for producing high purity gold according to claim 1, characterized in that: in the step S3, the mass fraction of the nitric acid solution is 40-65%, and the temperature is 70-80 ℃.
8. The process for producing high-purity gold according to claim 7, wherein: in the step S3, the soaking times are 2-4 times, the soaking time is 0.5-1h each time, and the nitric acid solution is replaced by the soaking time each time.
9. The process for producing high purity gold according to claim 1, characterized in that: in the step S4, the temperature of the pure water is 60-80 ℃.
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| CN113046568A (en) * | 2021-02-04 | 2021-06-29 | 深圳市金正龙科技有限公司 | Method for refining gold by controlling potential |
| CN114669754A (en) * | 2022-03-04 | 2022-06-28 | 金川集团股份有限公司 | Method for efficiently purifying gold from alloyed gold |
| CN115094243A (en) * | 2022-07-08 | 2022-09-23 | 山东招金金银精炼有限公司 | Method for removing impurity silver in preparation process of high-purity gold |
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| CN113046568A (en) * | 2021-02-04 | 2021-06-29 | 深圳市金正龙科技有限公司 | Method for refining gold by controlling potential |
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| CN115094243A (en) * | 2022-07-08 | 2022-09-23 | 山东招金金银精炼有限公司 | Method for removing impurity silver in preparation process of high-purity gold |
| CN115094243B (en) * | 2022-07-08 | 2023-09-12 | 山东招金金银精炼有限公司 | Method for removing impurity silver in high-purity gold preparation process |
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