Method and equipment for directly synthesizing potassium aurous cyanide

Abstract

The invention belongs to the technical field of preparation of potassium aurous cyanide, and particularly relates to a method and equipment for directly synthesizing potassium aurous cyanide, when the concentration of a potassium cyanide solution is 1.5-2.5 mol / L, the concentration of a potassium hydroxide solution is 2-3 mol / L, the reaction temperature is 50-80 DEG C, and the gold potential is kept within the range of-400 mV to-800 mV, the concentration of the potassium aurous cyanide solution is relatively high, and the potassium aurous cyanide solution can be directly synthesized. The reaction speed is high, during electrolytic reaction, continuous electrolysis is carried out by controlling the temperature to be 60-65 DEG C, the voltage to be 6-7 V and the current density to be 100-200 A / m < 2 >, the concentration of a potassium aurous cyanide solution is larger, the design of reaction condition parameters is better and is closer to a saturated state, and the reaction time needs to be set to be longer than 1 h in actual processing production; and gold powder is used for replacing gold flakes for reaction, so that the reaction time can be shortened, and the working efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of potassium aurous cyanide preparation, in particular to a method and equipment for directly synthesizing potassium aurous cyanide. Background Art

[0002] Potassium cyanogen gold is commonly known as gold salt, and its chemical formula is KAu(CN)2. Potassium cyanogen gold is a very important chemical reagent in gold plating and alloying processes. It is mainly used for electroplating and chemical gold plating. The coating is fine and bright, with strong corrosion resistance, good conductivity, and easy welding. It is widely used in the electroplating of parts that require long-term stable electrical parameter performance, such as precision instruments, printed circuit boards, integrated circuits, electronic tube shells, electrical contacts, as well as the electroplating of jewelry, watch parts, artworks, decorations and other products.

[0003] In the existing method for preparing synthetic potassium cyanogen gold, the gold potential cannot be controlled within a suitable range during the reaction process to ensure that the reaction can proceed smoothly and generate the target product; the reaction time is also not accurately controlled, resulting in a low yield of the target product.

[0004] To this end, the present invention provides a method and equipment for directly synthesizing potassium aurous cyanide. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for directly synthesizing potassium cyanogen gold according to the present invention comprises:

[0007] Add gold powder and deionized water into a reaction container and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction container;

[0008] During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed, and stirring is continued during the reaction to ensure that the reactants are fully mixed and reacted.

[0009] After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated to increase the concentration of potassium aurous cyanide;

[0010] The concentrated mother liquor is cooled and crystallized to obtain crude potassium aurous cyanide crystals, which are further purified by washing and recrystallization to obtain potassium aurous cyanide to improve its purity and quality.

[0011] Preferably, a gold electrode and a saturated calomel electrode are installed in the reaction container, the gold electrode is connected to the positive input terminal of the potentiometer through a wire, and the saturated calomel electrode is connected to the negative input terminal of the potentiometer through a wire.

[0012] Preferably, during the reaction, the reaction temperature is 50° C. to 80° C., the gold potential is maintained in the range of -400 mV to -800 mV, and stirring is continued during the reaction to ensure that the reactants are fully mixed and reacted.

[0013] Preferably, the concentration of the potassium cyanide solution is 1.5 to 2.5 mol / L, and the concentration of the potassium hydroxide solution is 2 to 3 mol / L.

[0014] Preferably, the obtained mother liquor is evaporated and concentrated, specifically:

[0015] The mother liquor obtained by the reaction is transferred to an evaporator, and the heating power and heating time of the evaporator are adjusted according to the concentration of the solution;

[0016] Start the heater to heat the mother liquor in the evaporator. During the evaporation and concentration process, the heating power and heating time should be kept stable to ensure uniform evaporation of the solution. During the heating process, pay close attention to the temperature and evaporation rate of the solution to avoid excessive temperature causing violent boiling and splashing of the solution.

[0017] The steam generated by evaporation is condensed through a condenser to recover the solvent, and the condensed solvent flows back to the evaporator for reuse;

[0018] When the desired concentration is reached by evaporation, the heating is stopped and the equipment is shut down, and the concentrated solution is transferred out of the evaporator for subsequent treatment.

[0019] Preferably, after the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities, specifically:

[0020] Secure the funnel to the stand and place the receiving container underneath it;

[0021] Place one or more layers of filter cloth in the funnel, ensure that the filter cloth fits tightly against the inner wall of the funnel, slowly pour the reaction mixture into the funnel, and the filtrate flows into the receiving container through the filter cloth and is collected for subsequent processing; after the filtration is completed, collect the filter residue in the funnel, wash, dry and recycle it to achieve the purpose of removing unreacted gold powder and impurities.

[0022] Preferably, during the electrolysis reaction, the temperature is controlled at 60-65°C, the voltage is 6-7V, and the current density is 100-200A / m2 for continuous electrolysis.

[0023] Preferably, during evaporation concentration, the temperature is 80-85° C., and the solution is concentrated to a saturated state.

[0024] Preferably, when the concentrated mother liquor is cooled and crystallized, the crystallization temperature is 60-70° C., and the crystals are stirred and washed with deionized water.

[0025] A device for directly synthesizing potassium aurous cyanide, comprising:

[0026] A reaction container, used for electrolytic reaction, in which a gold electrode and a saturated calomel electrode are installed, the gold electrode is connected to the positive input terminal of the potentiometer through a wire, and the saturated calomel electrode is connected to the negative input terminal of the potentiometer through a wire;

[0027] An evaporator is used to evaporate the obtained mother solution, and the heating power and heating time of the evaporator are adjusted according to the concentration of the solution by a heater;

[0028] Funnel, install the funnel directly on the surface, lay filter cloth inside the funnel, and set a collecting container directly below the funnel to collect the filtrate.

[0029] The beneficial effects of the present invention are as follows:

[0030] The method and equipment for directly synthesizing potassium aurous cyanide of the present invention comprises the following steps: the concentration of potassium cyanide solution is 1.5-2.5 mol / L, the concentration of potassium hydroxide solution is 2-3 mol / L, the reaction temperature is 50-80°C, and the gold potential is kept in the range of -400mV--800mV for reaction. The potassium aurous cyanide solution has a higher concentration and a faster reaction speed. During the electrolytic reaction, the temperature is controlled at 60-65°C, the voltage is 6-7V, and the current density is continuously electrolyzed at 100-200A / m2. The potassium aurous cyanide solution has a higher concentration, the reaction condition parameters are better designed, and the reaction is closer to a saturated state. In actual processing and production, the reaction time needs to be set to be greater than 1h. Moreover, gold powder should be used to replace gold sheets for reaction, so as to reduce the reaction time and improve work efficiency. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0032] Example 1

[0033] A method for directly synthesizing potassium gold cyanide according to an embodiment of the present invention comprises:

[0034] Add gold powder and deionized water into a reaction vessel and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction vessel according to the solution, the concentration of potassium cyanide solution is 1.5 mol / L, and the concentration of potassium hydroxide solution is 2 mol / L;

[0035] During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed. During the reaction, the reaction temperature is 50°C, and the gold potential is maintained in the range of -400mV for reaction. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted.

[0036] After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated at a temperature of 80° C., and the solution is concentrated to a saturated state to increase the concentration of potassium aurous cyanide;

[0037] The concentrated mother liquor is cooled and crystallized at a temperature of 60°C, and the crystals are stirred and washed with deionized water to obtain crude potassium aurous cyanide crystals. The crystals are further purified by washing and recrystallization processes to obtain potassium aurous cyanide to improve its purity and quality.

[0038] Example 2

[0039] A method for directly synthesizing potassium gold cyanide according to an embodiment of the present invention comprises:

[0040] Add gold powder and deionized water into a reaction vessel and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction vessel according to the solution, the concentration of potassium cyanide solution is 2.5 mol / L, and the concentration of potassium hydroxide solution is 3 mol / L;

[0041] During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed. During the reaction, the reaction temperature is 80°C, and the gold potential is maintained in the range of -800mV for reaction. Stirring is continued during the reaction to ensure that the reactants are fully mixed and reacted. Stirring is continued during the reaction to ensure that the reactants are fully mixed and reacted.

[0042] After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated at a temperature of 85° C., and the solution is concentrated to a saturated state to increase the concentration of potassium aurous cyanide;

[0043] The concentrated mother liquor is cooled and crystallized at a temperature of 70°C, and the crystals are stirred and washed with deionized water to obtain crude potassium aurous cyanide crystals. The crystals are further purified by washing and recrystallization processes to obtain potassium aurous cyanide to improve its purity and quality.

[0044] Example 3

[0045] A method for directly synthesizing potassium gold cyanide according to an embodiment of the present invention comprises:

[0046] Add gold powder and deionized water into a reaction vessel and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction vessel according to the solution, the concentration of potassium cyanide solution is 2 mol / L, and the concentration of potassium hydroxide solution is 2.5 mol / L;

[0047] During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed. During the reaction, the reaction temperature is 65°C, and the gold potential is kept in the range of -600mV for reaction. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted.

[0048] After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated at a temperature of 82° C., and the solution is concentrated to a saturated state to increase the concentration of potassium aurous cyanide;

[0049] The concentrated mother liquor is cooled and crystallized at a temperature of 65°C, and the crystals are stirred and washed with deionized water to obtain crude potassium aurous cyanide crystals. The crystals are further purified by washing and recrystallization processes to obtain potassium aurous cyanide to improve its purity and quality.

[0050] Example 4

[0051] A method for directly synthesizing potassium gold cyanide according to an embodiment of the present invention comprises:

[0052] Add gold powder and deionized water into a reaction vessel and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction vessel according to the solution, the concentration of potassium cyanide solution is 3 mol / L, and the concentration of potassium hydroxide solution is 4 mol / L;

[0053] During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed. During the reaction, the reaction temperature is 90°C, and the gold potential is kept in the range of -1000mV for reaction. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted. The reaction is continuously stirred during the reaction to ensure that the reactants are fully mixed and reacted.

[0054] After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated at a temperature of 90° C., and the solution is concentrated to a saturated state to increase the concentration of potassium aurous cyanide;

[0055] The concentrated mother liquor is cooled and crystallized at a temperature of 80°C, and the crystals are stirred and washed with deionized water to obtain crude potassium aurous cyanide crystals. The crystals are further purified by washing and recrystallization processes to obtain potassium aurous cyanide to improve its purity and quality.

[0056] Example 5

[0057] The difference between this embodiment and embodiment 1 is that during the electrolysis reaction, the temperature is controlled at 60°C, the voltage is 6V, and the current density is continuously electrolyzed at 100A / m2.

[0058] Example 6

[0059] The difference between this embodiment and embodiment 1 is that during the electrolysis reaction, the temperature is controlled at 65°C, the voltage is 7V, and the current density is continuously electrolyzed at 200A / m2.

[0060] Comparative Example 1

[0061] The difference between this embodiment and embodiments 1-3 is that gold flakes are used instead of gold powder for the reaction.

[0062] Potassium cyanogen gold was synthesized by the method of Examples 1-5 and Comparative Example 1. During the electrolysis reaction, the concentration of the potassium cyanogen gold solution was measured by an electrochemical sensor. The measured values ​​when the reaction time was 0.5 h and 1 h were recorded respectively. The test results are shown in the following table:

[0063]

[0064] Comparative Examples 1, 2, 3 and 4 show that when the concentration of potassium cyanide solution is 1.5 to 2.5 mol / L, the concentration of potassium hydroxide solution is 2 to 3 mol / L, the reaction temperature is 50° C. to 80° C., and the gold potential is kept in the range of -400 mV to -800 mV for reaction, the solution concentration of potassium cyanogen gold is large and the reaction speed is fast.

[0065] By comparing Examples 1-3 and 4-5, it can be seen that during the electrolysis reaction, the temperature is controlled at 60-65°C, the voltage is 6-7V, the current density is continuously electrolyzed at 100-200A / m2, the solution concentration of potassium gold cyanide is higher, the design of the reaction condition parameters is better, and it is closer to a saturated state. In actual processing and production, the reaction time needs to be set to be greater than 1h.

[0066] By comparing Examples 1-3 with Comparative Example 1, it can be seen that when the gold powder is replaced with gold flakes for reaction, the reaction rate is significantly lowered, which shows that gold powder is more suitable for the process of directly synthesizing potassium aurous cyanide.

[0067] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for directly synthesizing potassium aurous cyanide, characterized in that: include Add gold powder and deionized water into a reaction container and stir to ensure that the gold powder is evenly dispersed in the deionized water; gradually add potassium cyanide and hydrogen peroxide solution into the reaction container; During the electrolytic reaction, the gold potential in the reaction system is measured by a potentiometer, and the addition rate of potassium cyanide and hydrogen peroxide is adjusted as needed, and stirring is continued during the reaction; After the reaction is completed, the reaction mixture is filtered to remove unreacted gold powder and impurities; then, the obtained mother liquor is evaporated and concentrated; The concentrated mother liquor is cooled and crystallized to obtain crude potassium aurous cyanide crystals, and the crystals are further purified by washing and recrystallization to obtain potassium aurous cyanide.

2. A method for directly synthesizing potassium cyanogen gold according to claim 1, characterized in that: A gold electrode and a saturated calomel electrode are installed in a reaction container. The gold electrode is connected to the positive input terminal of the potentiometer through a wire, and the saturated calomel electrode is connected to the negative input terminal of the potentiometer through a wire.

3. A method for directly synthesizing potassium cyanogenide according to claim 2, characterized in that: During the reaction, the reaction temperature is 50° C. to 80° C., the gold potential is maintained in the range of -400 mV to -800 mV, and stirring is continued during the reaction.

4. A method for directly synthesizing potassium cyanogenide according to claim 3, characterized in that: The concentration of the potassium cyanide solution is 1.5-2.5 mol / L, and the concentration of the potassium hydroxide solution is 2-3 mol / L.

5. A method for directly synthesizing potassium cyanogenide according to claim 1, characterized in that: The obtained mother liquor is evaporated and concentrated, specifically: The mother liquor obtained by the reaction is transferred to an evaporator, and the heating power and heating time of the evaporator are adjusted according to the concentration of the solution; Start the heater to heat the mother liquid in the evaporator; The steam generated by evaporation is condensed through a condenser to recover the solvent, and the condensed solvent flows back to the evaporator for reuse; When the desired concentration is reached by evaporation, the heating is stopped and the equipment is shut down, and the concentrated solution is transferred out of the evaporator for subsequent treatment.

6. A method for directly synthesizing potassium cyanogenide according to claim 1, characterized in that: When the reaction is complete, the reaction mixture is filtered to remove unreacted gold powder and impurities, specifically: Secure the funnel to the stand and place the receiving container underneath it; Place one or more layers of filter cloth in the funnel, ensure that the filter cloth fits tightly against the inner wall of the funnel, slowly pour the reaction mixture into the funnel, and the filtrate flows into the receiving container through the filter cloth and is collected for subsequent processing; after the filtration is completed, collect the filter residue in the funnel, wash, dry and recycle it to achieve the purpose of removing unreacted gold powder and impurities.

7. A method for directly synthesizing potassium cyanogenide according to claim 1, characterized in that: During the electrolysis reaction, the temperature is controlled at 60-65°C, the voltage is 6-7V, and the current density is 100-200A / m2 for continuous electrolysis.

8. A method for directly synthesizing potassium gold cyanide according to claim 1, characterized in that: During evaporation concentration, the temperature is 80-85°C and the solution is concentrated to saturation.

9. A method for directly synthesizing potassium gold cyanide according to claim 1, characterized in that: When the concentrated mother liquor is cooled and crystallized, the crystallization temperature is 60-70°C, and the crystals are stirred and washed with deionized water.

10. A device for directly synthesizing potassium aurous cyanide, using the method for directly synthesizing potassium aurous cyanide according to claim 1, characterized in that: include: A reaction container, used for electrolytic reaction, in which a gold electrode and a saturated calomel electrode are installed, the gold electrode is connected to the positive input terminal of the potentiometer through a wire, and the saturated calomel electrode is connected to the negative input terminal of the potentiometer through a wire; An evaporator is used to evaporate the obtained mother solution, and the heating power and heating time of the evaporator are adjusted according to the concentration of the solution by a heater; Funnel, install the funnel directly on the surface, lay filter cloth inside the funnel, and set a collecting container directly below the funnel to collect the filtrate.

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