Method for recovering gold through reverse extraction

Abstract

The method for recovering gold through reverse extraction comprises the following steps: carrying out two-stage extraction on a chloridized gold leaching solution by adopting an extracting agent, and separating to obtain a gold-loaded organic phase; mixing the gold-loaded organic phase with a hydrochloric acid solution, performing ultrasonic enhanced cleaning, and standing for layering to obtain a purified gold-loaded organic phase; and after the purified gold-loaded organic phase is mixed with a stripping agent, ultrasonic reduction stripping and solid-liquid separation are conducted to obtain gold powder, the gold powder is washed, and high-purity gold powder is obtained. According to the preparation method provided by the invention, decomposition and polymerization among reactants are accelerated and the mass transfer process is enhanced by utilizing a mechanical effect, a thermal effect and a cavitation effect generated when ultrasonic waves are propagated in a medium, and multi-stage reverse extraction in a conventional process is avoided; the coarse gold powder obtained through reverse extraction is subjected to ultrasonic cleaning, the working procedures of long-time soaking with ethyl alcohol for deoiling and repeated boiling and washing with acid for impurity removal in the prior art are omitted, the method is energy-saving, efficient and environmentally friendly, the reverse extraction rate is increased by 1.67% compared with that of conventional first-stage reverse extraction, and the method is of great significance to high gold prices.

Description

Technical Field

[0001] The invention relates to the technical field of precious metal recovery from solid waste resources, and in particular to a method for recovering gold through stripping. Background Art

[0002] Gold has excellent electrical conductivity, thermal conductivity, corrosion resistance, and oxidation resistance and is widely used in high-tech fields such as aerospace, electronic communications, and optoelectronics. However, with the increasing shortage of easily selected gold ore resources and the rapid development of science and technology and the electronics industry, anode mud, alloy waste, and electronic waste such as waste circuit boards have become extremely important precious metal resources. Recovering gold and other valuable metals from these solid waste secondary resources to prepare high-purity gold can achieve resource reuse.

[0003] Solvent extraction is a traditional method for extracting precious metals. It has a good separation effect on precious metals such as gold and has become an important technology for recovering gold from gold-containing materials such as electronic waste, anode mud, and waste circuit boards to prepare high-purity gold. It is the most widely used.

[0004] Usually, electronic waste, anode mud, waste circuit boards and other gold-containing materials are pre-treated and then leached by chlorination to make liquid. After making liquid, solvent extraction, organic phase washing and impurity removal, reduction stripping, reduction gold powder boiling and washing, and drying are used to obtain high-purity gold. However, the existing reduction stripping process has problems such as large reagent consumption, long stripping time, low gold stripping rate, and the need for multi-stage stripping, which need to be improved. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides a method for recovering gold by stripping, so as to improve the efficiency and yield of reducing and stripping gold from a gold-carrying organic phase.

[0006] The specific content of the invention is as follows:

[0007] In a first aspect, the present invention provides a method for recovering gold by stripping, the method comprising the following steps:

[0008] S1, using an extractant to perform two-stage extraction on the chlorinated gold leaching solution to separate and obtain a gold-carrying organic phase;

[0009] S2, mixing the gold-loaded organic phase with a hydrochloric acid solution at a ratio of 2:1, placing the mixture in an ultrasonic instrument, performing ultrasonic enhanced cleaning at 25-50° C., and allowing the mixture to stand for stratification to obtain a purified gold-loaded organic phase;

[0010] S3, mixing the purified gold-loaded organic phase with a stripping agent, placing the mixture in an ultrasonic instrument, performing ultrasonic reduction stripping at 25-80° C., separating the solid from the liquid to obtain a crude gold powder, and washing the crude gold powder to obtain a high-purity gold powder;

[0011] The stripping agent is formed by mixing a reducing agent and an additive in a volume ratio of 4:1-8:1, wherein the reducing agent is a 5-10% oxalic acid solution and the additive is a 10-20% sodium hydroxide solution;

[0012] The extractant is any one of dibutyl carbitol, methyl isobutyl ketone and tributyl phosphate, or a plurality of them mixed in any proportion.

[0013] Optionally, in step S2, the ultrasonic enhanced cleaning is controlled at an ultrasonic frequency of 25-100 kHz, an ultrasonic power of 120-300 W, and an ultrasonic time of 5-15 min.

[0014] Optionally, in step S2, the concentration of the hydrochloric acid solution is 1.0-2.0 mol / L.

[0015] Optionally, the ultrasonic reduction stripping control has an ultrasonic frequency of 45-100 kHz, an ultrasonic power of 120-300 W, and an ultrasonic reduction stripping time of 10-30 min.

[0016] Optionally, in step S3, the amount of stripping agent added to the purified gold-loaded organic phase is 1.5-3 times the gold content of the solution.

[0017] Optionally, in step S3, the washing includes: ultrasonically washing the coarse gold powder with deionized water until the solution is neutral, separating the solid from the liquid, and drying to obtain high-purity gold powder.

[0018] Optionally, the ultrasonic washing is controlled at an ultrasonic temperature of 25-50° C., an ultrasonic frequency of 25-100 kHz, an ultrasonic power of 120-300 W, and an ultrasonic cleaning time of 5-10 min.

[0019] Optionally, in step S1, the two-stage extraction comprises:

[0020] S101, mixing the extractant and the chlorinated gold leaching solution in a ratio of O / A=1:2 in a separatory funnel, placing the mixture on a separatory funnel oscillator to mix thoroughly, standing for 30 minutes, and separating the organic phase and the primary raffinate;

[0021] S102, continue to add the extractant to the primary raffinate, and repeat step S101 to perform secondary extraction; after the organic phases obtained from the two-stage extraction are combined, the gold-loaded organic phase is obtained.

[0022] Optionally, in step S1, the acid concentration of the chlorinated gold leaching solution is 1-2 mol / L.

[0023] Optionally, in step S3, the ultrasonic instrument is a single-frequency ultrasonic instrument or a variable-frequency ultrasonic instrument.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention provides a method for recovering gold by stripping, which comprises the following steps: S1, using an extractant to perform two-stage extraction on a chlorinated gold leaching solution to separate and obtain a gold-carrying organic phase; S2, mixing the gold-carrying organic phase with a hydrochloric acid solution, performing ultrasonic enhanced cleaning at 25-50°C, and obtaining a purified gold-carrying organic phase after standing and stratification; S3, mixing the purified gold-carrying organic phase with a stripping agent, placing the mixture in an ultrasonic instrument, performing ultrasonic reduction stripping at 25-80°C, obtaining gold powder by solid-liquid separation, and washing the gold powder to obtain high-purity gold powder.

[0026] In the preparation method provided by the present invention, the mechanical effect, thermal effect and cavitation effect generated when ultrasonic waves propagate in the medium are utilized, and by adjusting the parameters of ultrasonic waves, whether it is the cleaning and impurity removal of the gold-carrying organic phase or the reduction and stripping of the gold-carrying organic phase in the stripping system, the decomposition and polymerization between the reactants are accelerated, the mass transfer process is strengthened, the reaction time is shortened, and the stripping rate is improved; in addition, the gold powder is subjected to ultrasonic cleaning by reduction and stripping, and the degreasing process is strengthened under the action of ultrasonic waves, and the organic phase on the surface of the gold powder is emulsified, thereby quickly separating from the gold powder, eliminating the steps of repeated boiling and washing with ethanol to remove oil and acid washing to remove impurities in the previous process, and the degreasing and degreasing are completed in one step. On the whole, the optimized preparation method is more energy-saving, efficient, and green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A flow chart of a method for recovering gold by stripping provided in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the embodiments of the present invention, any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts falls within the scope of protection of the present invention. In addition, all other embodiments obtained by ordinary technicians in this field without carrying out creative work belong to the scope of protection of the present invention.

[0030] In the embodiment, no specific experimental steps or conditions are indicated, and the operation or conditions of the conventional experimental steps described in the prior art in this field can be carried out. The reagents used and other instruments that do not indicate the manufacturer are conventional reagent products that can be obtained commercially. In addition, the accompanying drawings are only schematic diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the description of the present invention.

[0032] In the description of the present invention, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0033] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Usually, gold-containing materials such as electronic waste and anode mud are pretreated and then chlorinated and leached to make liquid. After making liquid, solvent extraction, organic phase washing and impurity removal, reduction stripping, reduction gold powder boiling and washing, and drying are used to obtain high-purity gold. Among them, the extraction and organic phase washing processes are relatively mature, but for the reduction stripping of the gold-carrying organic phase, the commonly used reducing agents are oxalic acid and sodium sulfite. When oxalic acid is used as a reducing agent, the reduction temperature needs to be above 70°C, the stirring reduction stripping time is 2-3 hours or even longer, and multiple stripping is required; when sodium sulfite is used as a reducing agent, although it can be carried out at room temperature, it requires a long reaction time, a large amount of reagent consumption, and trace gold is easy to appear at the interface between the two phases, and the gold precipitation efficiency is not high. These conventional reduction stripping generally need to be repeated many times to increase the gold yield, and the process produces acidic gas, which has a great impact on the environment.

[0035] The present invention aims to solve the problems of large reagent consumption, long stripping time and low gold yield in the reduction stripping process of gold-loaded organic phase, and provides a method for recovering gold by stripping. The specific implementation contents are as follows:

[0036] In a first aspect, the present invention provides a method for recovering gold through stripping. Figure 1 The flowchart of the method for recovering gold by stripping provided by an embodiment of the present invention is shown as follows: Figure 1 As shown, the method comprises the following steps:

[0037] S1, using an extractant to perform two-stage extraction on the chlorinated gold leaching solution to separate and obtain a gold-carrying organic phase;

[0038] S2, mixing the gold-loaded organic phase with a hydrochloric acid solution at a ratio of 2:1, placing the mixture in an ultrasonic instrument, performing ultrasonic enhanced cleaning at 25-50° C., and allowing the mixture to stand for stratification to obtain a purified gold-loaded organic phase;

[0039] S3. After mixing the purified gold-loaded organic phase with a stripping agent, the mixture is placed in an ultrasonic instrument, and ultrasonic reduction stripping is performed at 25-80° C. to obtain a coarse gold powder by solid-liquid separation, and the coarse gold powder is washed to obtain a high-purity gold powder.

[0040] In specific implementation, the present invention adopts two-stage extraction separation to obtain the gold-carrying organic phase, and the specific operation steps include:

[0041] S101, mixing the extractant and the chlorinated gold leaching solution in a ratio of O / A=1:2 in a separatory funnel, placing the mixture on a separatory funnel oscillator to mix thoroughly, standing for 30 minutes, and separating the organic phase and the primary raffinate;

[0042] S102, continue to add the extractant to the primary raffinate, repeat step S101 to perform secondary extraction; after the organic phases obtained by the two-stage extraction are combined, the gold-loaded organic phase is obtained. The extractant is selected from any one of dibutyl carbitol (DBC), methyl isobutyl ketone (MIBK) and tributyl phosphate (TBP), or a mixture of multiple agents in any proportion.

[0043] Furthermore, in the embodiment of the present invention, ultrasonic waves are used to purify the gold-loaded organic phase. The ultrasonic enhanced cleaning is controlled by an ultrasonic frequency of 25-100 kHz, an ultrasonic power of 120-300 W, and an ultrasonic time of 5-15 min, thereby shortening the pickling time and enhancing the cleaning effect.

[0044] Furthermore, the embodiment of the present invention combines the reduction stripping process with the ultrasonic effect, performs ultrasonic reduction stripping at 25-80°C, and utilizes the mechanical effect, thermal effect and cavitation effect generated when ultrasonic waves propagate in the medium to accelerate the decomposition and polymerization between reactants, strengthen the mass transfer process, and shorten the reaction time. The stripping agent selected in this process is formed by mixing a reducing agent and an additive in a volume ratio of (4-8):1, wherein the reducing agent is an oxalic acid solution and the additive is a sodium hydroxide solution; the ultrasonic reduction stripping controls the ultrasonic frequency of 45-100kHz, the ultrasonic power of 120-300W, and the ultrasonic reduction stripping time of 10-30min.

[0045] In some embodiments, the amount of stripping agent added to the purified gold-loaded organic phase is 1.5-3 times the gold content in the solution.

[0046] In some embodiments, the operation of washing the crude gold powder can also be performed under ultrasonic action, including: ultrasonically washing the crude gold powder with deionized water until the solution is neutral, solid-liquid separation, and drying to obtain high-purity gold powder. The ultrasonic temperature controlled by ultrasonic washing is 25-50°C, the ultrasonic frequency is 25-100KHz, the ultrasonic power is 120-300W, and the ultrasonic cleaning time is 5-10min. The crude gold powder obtained by reduction stripping is ultrasonically cleaned, and the degreasing process is enhanced under the action of ultrasound. The organic phase on the surface of the gold powder is emulsified, thereby quickly separating from the gold powder, eliminating the process of long-term ethanol immersion for degreasing and repeated acid boiling and washing for impurities in the previous process, and degreasing and de-impurity are completed in one step.

[0047] In order to enable those skilled in the art to more clearly understand the present invention, the method for recovering gold by stripping according to the present invention is now described in detail through the following examples.

[0048] In the following examples, the gold-loaded organic phase for reduction stripping was prepared by extraction using the following method:

[0049] Take 500ml of extractant (volume ratio: DBC:TBP=4:1) and 1000ml of chlorinated gold leaching solution with an acid concentration of 1.0mol / L, mix them thoroughly on a separatory funnel oscillator for 5 minutes, let them stand for 30 minutes, and separate the organic phase and the first-stage raffinate; add the extractant again (phase ratio is 1:2) to the first-stage raffinate and repeat the above steps for the second-stage extraction. The organic phases of the two-stage extraction are combined to obtain the gold-carrying organic phase, and the raffinate is recovered.

[0050] Example 1

[0051] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 mol / L hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 2 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 45 kHz, and the ultrasonic power is 240 W, and the phase is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0052] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0053] Step 3: The crude gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 240W, and the high-purity gold powder is obtained by drying, and the reduction stripping rate is 98.72%.

[0054] Example 2

[0055] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 5 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 240 W, and the mixture is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0056] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic reduction stripping for 10 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 80kHz, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0057] Step 3: The crude gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 80kHz, the ultrasonic power is 240W, and the high-purity gold powder is obtained by drying, and the reduction stripping rate is 98.67%.

[0058] Example 3

[0059] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 5 min; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 300 W, and the mixture is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0060] Step 2: Add the purified gold-carrying organic phase to 45 ml of oxalic acid solution containing 5% of the reducing agent, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic reduction stripping for 15 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 100kHz, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0061] Step 3: The coarse gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 300W, and the gold powder is dried to obtain a reduction stripping rate of 99.42%.

[0062] Example 4

[0063] Step 1: Take 200 ml of the gold-loaded organic phase and dissolve it in 100 ml of 1.0 N hydrochloric acid, and perform ultrasonic washing in an ultrasonic cleaner for 5 minutes; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 300 W, and the mixture is allowed to stand for 10 minutes to separate the purified gold-loaded organic phase;

[0064] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 15 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 5min-80kHz / 5min- / 100kHz / 5min, the frequency conversion reduction stripping, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0065] Step 3: The crude gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 300W, and the gold powder is dried to obtain a reduction stripping rate of 99.694%.

[0066] Example 5

[0067] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 6 min; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz / 2 min--80 kHz / 2 min-100 kHz / 2 min, the frequency conversion cleaning, the ultrasonic power is 240 W, and the mixture is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0068] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase and dropwise add 5.2 ml of 20% sodium hydroxide solution for ultrasonic stripping for 15 min; wherein, the ultrasonic temperature is 70°C, the ultrasonic frequency is 45kHz / 5min-80kHz / 5min- / 100kHz5min, the frequency conversion reduction stripping, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0069] Step 3: The coarse gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 6 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 2min-80kHz / 2min- / 100kHz / 2min, variable frequency cleaning, ultrasonic power is 240W, and the gold powder is dried, and the reduction stripping rate is 99.53%.

[0070] Example 6

[0071] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 6 minutes; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz / 3 min-80 kHz / 3 min, the frequency conversion ultrasonic cleaning is performed, the ultrasonic power is 300 W, and the mixture is allowed to stand for 10 minutes to separate the purified gold-loaded organic phase;

[0072] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 min; wherein, the ultrasonic temperature is 70°C, the ultrasonic frequency is 45kHz / 5min- / 100kHz / 5min, the frequency conversion stripping, and the ultrasonic power is 300W; filter to obtain coarse gold powder;

[0073] Step 3: After filtering the coarse gold powder, ultrasonic cleaning is performed with deionized water until the solution is neutral, each time for 6 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 3min-80kHz / 3min, the ultrasonic power is 300W, and the gold powder is dried to obtain a reduction stripping rate of 99.72%.

[0074] Example 7

[0075] Similar to Example 1, the specific steps refer to Example 1, except that the ultrasonic frequency of step 1 is different, and the method includes the following steps:

[0076] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 mol / L hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 2 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 80 kHz, the ultrasonic power is 240 W, and the phases are allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0077] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0078] Step 3: After filtering the coarse gold powder, ultrasonic cleaning is performed with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction stripping rate of 98.52%.

[0079] Example 8

[0080] Similar to Example 1, the specific steps refer to Example 1, except that the ultrasonic frequency in step 3 is different, and the steps include:

[0081] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 mol / L hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 2 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 240 W, and the phases are allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0082] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-loaded organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 min; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45 kHz, and the ultrasonic power is 240 W;

[0083] Step 3: After the gold powder is filtered, it is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 80kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction and stripping rate of 98.22%.

[0084] Example 9

[0085] Similar to Example 1, the difference is that the ultrasonic frequency in step 2 is different, and specifically includes the following steps:

[0086] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 mol / L hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 2 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 80%, and the separation is performed after standing for 10 min to separate the purified gold-loaded organic phase;

[0087] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-loaded organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 min; wherein, the ultrasonic temperature is 50° C., the ultrasonic frequency is 100 kHz, and the ultrasonic power is 240 W;

[0088] Step 3: After the gold powder is filtered, it is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction and stripping rate of 99.08%.

[0089] Example 10

[0090] Similar to Example 1, refer to Example 1, the difference is that the reduction stripping temperature in step 2 is different, and specifically includes the following steps:

[0091] Step 1: Take 100 ml of the gold-loaded organic phase and 50 ml of a 1.0 mol / L hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 2 min; wherein the ultrasonic temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 80%, and the phase is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0092] Step 2: Add 22.5 ml of oxalic acid solution with 5% reducing agent and drop 2.6 ml of 20% sodium hydroxide solution to the purified gold-loaded organic phase for ultrasonic stripping for 10 min; wherein, the ultrasonic temperature is 70°C, the ultrasonic frequency is 45 kHz, and the ultrasonic power is 240 W;

[0093] Step 3: After the gold powder is filtered, it is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction and stripping rate of 99.31%.

[0094] Embodiment 11

[0095] Similar to Example 2, the difference is that the reduction stripping temperature in step 2 is different, and specifically includes the following steps:

[0096] Step 1: Take 100 ml of the gold-loaded organic phase and 50 ml of 1.0 N hydrochloric acid solution and ultrasonically wash them in an ultrasonic cleaner for 5 minutes; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 240 W, and the mixture is allowed to stand for 10 minutes to separate the purified gold-loaded organic phase;

[0097] Step 2: Add 22.5 ml of 5% oxalic acid solution as a reducing agent to the purified gold-loaded organic phase and dropwise add 2.6 ml of 20% sodium hydroxide solution for ultrasonic reduction stripping for 10 min; wherein the ultrasonic temperature is 70°C, the ultrasonic frequency is 80 kHz, and the ultrasonic power is 240 W;

[0098] Step 3: After the gold powder is filtered, it is ultrasonically cleaned with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 80kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction and stripping rate of 99.01%.

[0099] Example 12

[0100] Similar to Example 3, the difference is that the reduction stripping time in step 2 is different, and specifically includes the following steps:

[0101] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution and perform ultrasonic washing in an ultrasonic cleaner for 5 min; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 300 W, and the mixture is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0102] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution for ultrasonic stripping for 20 min; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 100 kHz, and the ultrasonic power is 300 W; filter to obtain coarse gold powder;

[0103] Step 3: ultrasonically clean the coarse gold powder with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50° C., the ultrasonic frequency is 45 kHz, the ultrasonic power is 300 W, and the gold powder is dried to obtain a reduction stripping rate of 99.42%.

[0104] Embodiment 13

[0105] Similar to Example 4, the difference is that the reduction stripping temperature in step 2 is different, and specifically includes the following steps:

[0106] Step 1: Take 200 ml of the gold-loaded organic phase and dissolve it in 100 ml of 1.0 N hydrochloric acid, and perform ultrasonic washing in an ultrasonic cleaner for 5 minutes; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz, the ultrasonic power is 240 W, and the mixture is allowed to stand for 10 minutes to separate the purified gold-loaded organic phase;

[0107] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and dropwise add 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 15 minutes; wherein, the ultrasonic temperature is 70°C, the ultrasonic frequency is 45kHz / 5min-80kHz / 5min- / 100kHz / 5min, the frequency conversion stripping, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0108] Step 3: After filtering the coarse gold powder, ultrasonic cleaning is performed with deionized water until the solution is neutral, each time for 5 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction stripping rate of 99.71%.

[0109] Embodiment 15

[0110] Similar to Example 5, the difference is that the ultrasonic time of step 1 and step 2 and the ultrasonic frequency of step 3 are different, and specifically includes the following steps:

[0111] Step 1: Take 200 ml of the gold-carrying organic phase and 100 ml of a 1.0N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 6 minutes; wherein the temperature is room temperature, the ultrasonic frequency is 45kHz / 3min-80kHz / 3min, the triple-frequency variable frequency ultrasonic stripping, the ultrasonic power is 80%, and the mixture is allowed to stand for 10 minutes to separate the purified gold-carrying organic phase;

[0112] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase and dropwise add 5.2 ml of 20% sodium hydroxide solution for ultrasonic stripping for 15 min; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 3min-80kHz / 6min- / 100kHz6min, the three-frequency variable frequency stripping, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0113] Step 3: The crude gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 6 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 3min-80kHz / 3min, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction stripping rate of 99.90%.

[0114] Example 16

[0115] Similar to Example 6, the difference is that the ultrasonic powers of step 1, step 2 and step 3 are different, and specifically include the following steps:

[0116] Step 1: Take 200 ml of the gold-loaded organic phase and 100 ml of a 1.0 N hydrochloric acid solution, and perform ultrasonic washing in an ultrasonic cleaner for 6 min; wherein the temperature is room temperature, the ultrasonic frequency is 45 kHz / 3 min-80 kHz / 3 min, the frequency conversion ultrasonic cleaning is performed, the ultrasonic power is 240 W, and the mixture is allowed to stand for 10 min to separate the purified gold-loaded organic phase;

[0117] Step 2: Add 45 ml of 5% oxalic acid solution as a reducing agent to the purified gold-carrying organic phase, and drop 5.2 ml of 20% sodium hydroxide solution, and perform ultrasonic stripping for 10 min; wherein, the ultrasonic temperature is 70°C, the ultrasonic frequency is 45kHz / 5min- / 100kHz / 5min, the double-frequency variable frequency stripping, and the ultrasonic power is 240W; filter to obtain coarse gold powder;

[0118] Step 3: The crude gold powder is ultrasonically cleaned with deionized water until the solution is neutral, each time for 6 minutes; wherein, the ultrasonic temperature is 50°C, the ultrasonic frequency is 45kHz / 3min-80kHz / 3min, the ultrasonic power is 240W, and the gold powder is dried to obtain a reduction stripping rate of 99.69%.

[0119] Comparative Example 1

[0120] It is a traditional reduction stripping process, which specifically includes the following steps:

[0121] Step 1: Take 100 ml of the gold-loaded organic phase and 50 ml of 1.0 N hydrochloric acid solution, mix them thoroughly in a separatory funnel oscillator for 5 min, let stand to separate the layers, and separate the organic phase;

[0122] Step 2: Place the organic phase after acid washing and purification in a beaker, add 22.5 ml of 5% oxalic acid solution and 2.6 ml of 20% sodium hydroxide solution, stir and reduce at a temperature of 80-85°C for 90 minutes; filter to obtain coarse gold powder;

[0123] Step 3: Use 1-3 mol / L hydrochloric acid to boil and wash the coarse gold powder, separate the washing liquid, and then repeatedly wash it with deionized water. Finally, soak it in 99.5% ethanol solution for no less than 24 hours to wash the oil. After washing, dry it. The primary reduction stripping rate of the gold powder is 98.23%.

[0124] The comparative test between traditional reduction stripping and ultrasonic enhanced reduction stripping is shown in Table 1.

[0125] Table 1 Comparative test of long gauge stripping and ultrasonic variable frequency stripping

[0126]

[0127] It can be seen that under the same process conditions, the ultrasonic enhanced stripping effect is better than the traditional stripping, and only one reduction is required; low-frequency ultrasound is more conducive to cleaning and deoiling (as can be seen from the comparison between Example 1 and Example 8), whether it is the acid elution of the organic phase or the water elution of the gold powder, the variable frequency ultrasound effect is better (as can be seen from the comparison between Example 2 and Example 6). Variable frequency ultrasound is more efficient and rapid for enhanced reduction stripping (as can be seen from the comparison between Example 3 and Example 4). Ultrasonic enhanced reduction stripping increases the stripping rate by 1.67% compared with conventional primary stripping (as can be seen from the comparison between Example 15 and Comparative Example 1), which is of great significance for the more effective recovery of gold and the high gold price.

[0128] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0129] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the order of the actions described, because according to the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and components involved are not necessarily required by the present invention.

[0130] The above is a detailed introduction to a method for recovering gold by stripping provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for recovering gold by stripping, characterized in that: The method comprises the following steps: S1, using an extractant to perform two-stage extraction on the chlorinated gold leaching solution to separate and obtain a gold-carrying organic phase; S2, mixing the gold-loaded organic phase with a hydrochloric acid solution at a ratio of 2:1, placing the mixture in an ultrasonic instrument, performing ultrasonic enhanced cleaning at 25-50° C., and allowing the mixture to stand for stratification to obtain a purified gold-loaded organic phase; S3, mixing the purified gold-loaded organic phase with a stripping agent, placing the mixture in an ultrasonic instrument, performing ultrasonic reduction stripping at 25-80° C., separating the solid from the liquid to obtain a crude gold powder, and washing the crude gold powder to obtain a high-purity gold powder; The stripping agent is formed by mixing a reducing agent and an additive in a volume ratio of (4-8):1, wherein the reducing agent is an oxalic acid solution and the additive is a sodium hydroxide solution; The extractant is any one of dibutyl carbitol, methyl isobutyl ketone and tributyl phosphate, or a plurality of them mixed in any proportion.

2. The method for recovering gold by stripping according to claim 1, characterized in that: In step S2, the ultrasonic enhanced cleaning is controlled at an ultrasonic frequency of 25-100 kHz, an ultrasonic power of 120-300w, and an ultrasonic time of 5-15min.

3. The method for recovering gold by stripping according to claim 1, characterized in that: In step S2, the concentration of the hydrochloric acid solution is 1.0-2.0 mol / L.

4. The method for recovering gold by stripping according to claim 1, characterized in that: In step S3, the ultrasonic reduction stripping is controlled at an ultrasonic frequency of 45-100 kHz, an ultrasonic power of 120-300 W, and a ultrasonic reduction stripping time of 10-30 min.

5. The method for recovering gold by stripping according to claim 1, characterized in that: In step S3, the amount of the stripping agent used is 1.5-3 times the gold content of the solution.

6. The method for recovering gold by stripping according to claim 1, characterized in that: In step S3, the washing includes: ultrasonically washing the coarse gold powder with deionized water until the solution is neutral, separating the solid and the liquid, and drying to obtain high-purity gold powder.

7. The method for recovering gold by stripping according to claim 6, characterized in that: The ultrasonic washing is controlled to have an ultrasonic temperature of 25-50° C., an ultrasonic frequency of 25-100 KHz, an ultrasonic power of 120-300 W, and an ultrasonic cleaning time of 5-10 min.

8. The method for recovering gold by stripping according to claim 1, characterized in that: In step S1, the two-stage extraction comprises: S101, mixing the extractant and the chlorinated gold leaching solution in a ratio of O / A=1:2 in a separatory funnel, placing the mixture on a separatory funnel oscillator to mix thoroughly, standing for 30 minutes, and separating the organic phase and the primary raffinate; S102, continue to add the extractant to the primary raffinate, and repeat step S101 to perform secondary extraction; after the organic phases obtained from the two-stage extraction are combined, the gold-loaded organic phase is obtained.

9. The method for recovering gold by stripping according to claim 1, characterized in that: In step S1, the acid concentration of the chlorinated gold leaching solution is 1-2 mol / L.

10. The method for recovering gold by stripping according to claim 1, characterized in that: In step S3, the ultrasonic instrument is a single-frequency ultrasonic instrument or a variable-frequency ultrasonic instrument.

Images