Process for improving grade of silver concentrate in zinc leaching residues by coupling single roughing of coal dressing foaming agent

Abstract

The invention discloses a process for improving the grade of silver concentrate of zinc leaching residues by coupling single roughing of a coal dressing foaming agent, which comprises the following steps of: washing, drying and sieving the silver concentrate of the zinc leaching residues with the silver grade of more than or equal to 3000g / t, taking an ore sample, performing ultrasonic treatment, and adding deionized water to adjust the concentration of ore pulp; adding a collecting agent dibutyl amine black powder and stirring; adding a foaming agent and stirring; finally, adding an inhibitor; and performing air inflation flotation. Experiments prove that the optimal addition amount of the dibutyl amine black powder is 200g / t, the silver grade of the concentrate is 4225g / t, the recovery rate is 48.11%, and the yield is 38.60%; the optimal addition amount of APG is 20 g / t, the silver grade is 4240 g / t, the recovery rate is 36.18%, and the yield is 28.93%; the optimal addition amount of MIBC is 30 g / t, the silver grade is 4080 g / t, the recovery rate is 52.63%, and the yield is 43.73%; therefore, compared with the original concentrate grade, the grade is obviously improved.

Description

Technical Field

[0001] The invention relates to the field of silver recovery in silver concentrate of zinc leaching slag, and in particular to a process for improving the grade of silver concentrate of zinc leaching slag by single roughing with a coupled coal preparation frother. Background Art

[0002] The silver recovery technology in silver concentrate of zinc leaching residue is mainly divided into two categories: hydrometallurgy and flotation. However, the existing technology has the following defects: cyanide toxic pollution, excessive COD of pine oil, starch inhibition leading to reduced recovery rate, MIBC alkaline environment failure, and complex multi-stage magnetic separation equipment.

[0003] APG is a green frother produced from natural renewable resources, green, non-toxic, and environmentally friendly starch or its hydrolyzed sugar condensed with fatty alcohol. It has low surface tension and interfacial tension, complex performance, low toxicity, rich foam, delicate and stable. It is currently mainly used for coal preparation, but has never been used for the flotation of silver-containing minerals, especially the complex system of silver concentrate from zinc leaching slag. Compared with traditional frothers (MIBC, pine oil), APG has the characteristics of biodegradability, non-toxicity, and renewable raw materials (plant extraction), which meets the green metallurgical needs under the policy. When silver is floated from silver concentrate from zinc leaching slag, the Mn, Cd and other ions remaining in the leaching slag may interfere with the recovery of silver; when APG is used as a frother, its metal ion complexing ability can simultaneously reduce the interference of impurity metals on the flotation process, reduce the impurity content in the concentrate, and improve the silver grade. Heavy metals (such as Zn and Cd) may remain in the flotation tailings. The addition of APG can reduce their environmental toxicity, facilitate subsequent resource utilization (such as making building materials or landfill), and form an integrated "flotation-tailings detoxification" process.

[0004] Chinese patent CN108393197A discloses a beneficiation method for recovering iron, carbon and silver from zinc leaching residue. The process flow is as follows: step 1: magnetic separation to remove iron (magnetic field strength 0.8T, iron recovery rate 85%); step 2: flotation of silver (butyl xanthate 200g / t + pine oil 150g / t, pH=7.0, slurry concentration 30%); step 3: gravity separation to recover carbon (shaking table separation, carbon grade increased to 65%); the results are: silver recovery rate 65%, Zn content in concentrate 15.2%; tailings COD value 5800mg / L. It can be seen that the disadvantages of this method are: 1. The environmental toxicity of the foaming agent is high: the biodegradation rate of pine oil is only 28% (data cited from Liang Yunfan's "The Effect and Mechanism of Foaming Agent on Flotation of High-ash Tailing Slime"), and the tailings COD exceeds the standard by 58 times (compared with the "Comprehensive Sewage Discharge Standard" GB8978-1996, the first-level limit of 100 mg / L). 2. Failure to suppress zinc and iron impurities: the Zn content in the concentrate reaches 15.2% (cited from Table 1 of the patent), and additional acid leaching is required to remove zinc, increasing the processing cost by 22% (calculated based on the consumption of 180 kg of H2SO4 per ton of concentrate). 3. The process flow is lengthy: the three-stage combined operation of magnetic separation-flotation-gravity separation increases the equipment investment cost by 40%.

[0005] Chinese patent CN111719050B discloses a method for comprehensive recovery of water-soluble zinc and silver in zinc leaching residue, the process flow is: step 1: sulfuric acid zinc leaching (H2SO4 concentration 1.5mol / L, zinc leaching rate 90%); step 2: cyanide silver leaching (NaCN3.5kg / t, leaching time 48 hours); step 3: zinc powder replacement (zinc powder dosage 2kg / t, silver recovery rate 75%). The result is: cyanide tail liquid CN- concentration 50mg / L (original text: "the residual concentration of cyanide ions in the leaching tail liquid is 50mg / L"); the replacement slag zinc content 25%. It can be seen that the disadvantages of this method are: 1. Environmental risk of highly toxic agents: the tail liquid CN- concentration exceeds the standard by 10 times (compared with the "Hazardous Waste Identification Standard" GB5085.3-2007 limit of 5mg / L), and additional detoxification facilities need to be built, increasing the cost by 30% (the economic analysis of the patent embodiment 4). 2. Low silver-zinc separation efficiency: 18% silver loss during zinc powder replacement (calculated based on the data in Table 2 of the patent: 100 kg silver input → 82 kg recovered). 3. Harsh reaction conditions: pH>10.5 must be maintained to prevent HCN volatilization (cited from paragraph

[0025] of the patent), resulting in an increase in lime consumption of 15 kg / t slag.

[0006] Therefore, the existing technology urgently needs breakthroughs in the construction of green pharmaceutical systems and the synergistic effects of inhibitors. Summary of the invention

[0007] In view of this, the present invention provides a process for improving the grade of zinc leaching slag silver concentrate by coupling a coal preparation frother with a single roughing process.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother, comprising the following steps:

[0010] Step 1: Wash and dry the silver concentrate slurry of zinc leaching slag with a silver grade of ≥3000g / t, sieve, then take a sample for ultrasonic treatment, and add deionized water to adjust the slurry concentration;

[0011] Step 2: first add the collector butylamine black medicine and stir; then add the foaming agent and stir; finally add the inhibitor;

[0012] Step 3: Perform aeration flotation.

[0013] Preferably, in step 1, an electric constant temperature blast drying oven is used for drying, the drying temperature is 70° C., and the drying time is 2 hours.

[0014] Preferably, in step 1, a standard vibrating screen is used for screening, and the product is passed through a 200-mesh screen with a pore size of 75 μm.

[0015] Preferably, in step 1, the ultrasonic power is 150 W, the ultrasonic frequency is 40 kHz, and the ultrasonic time is 2 minutes.

[0016] Preferably, in step 1, 15 g of ore sample is taken and the slurry concentration is adjusted to a mass fraction of 15%-16%.

[0017] Preferably, in step 2, the amount of butylamine black medicine added is 50-1000 g / t, and stirring is carried out for 3 minutes.

[0018] More preferably, the optimal addition amount of butylamine black medicine is 200g / t.

[0019] Preferably, in step 2, the foaming agent is APG alkyl glycoside or MIBC methyl isobutyl carbinol, wherein the amount of APG added is 10-80 g / t or the amount of MIBC added is 10-50 g / t, the stirring time is 1 minute, and the stirring speed is 800 rpm.

[0020] More preferably, the optimal addition amount of APG alkyl polyglycoside is 20 g / t; the optimal addition amount of MIBC methyl isobutyl carbinol is 30 g / t.

[0021] Preferably, when the foaming agent is APG, the pH is adjusted to 6.5-8.5, and when the foaming agent is MIBC, the pH is adjusted to 7.0-9.0.

[0022] Preferably, in step 2, the inhibitor is sodium sulfide, and the addition amount is 100g / t-500g / t.

[0023] Preferably, in step 3, the inflation volume is 0.2m 3 / h, the inflation pressure is 0.05MPa and the flotation time is 3 minutes.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] (1) The present invention adopts coal preparation foaming agent APG to replace the traditional foaming agent pine oil to realize a green agent system;

[0026] (2) The present invention specifically inhibits ZnCO3 by controlling the amount of sodium sulfide added, but does not affect Ag2S;

[0027] (3) The present invention has been verified by experiments. The optimal addition amount of butylamine black medicine is 200g / t, the silver grade of the concentrate is 4225g / t, the recovery rate is 48.11%, and the yield is 38.60%; the optimal addition amount of APG is 20g / t, the silver grade is 4240g / t, the recovery rate is 36.18%, and the yield is 28.93%; the optimal addition amount of MIBC is 30g / t, the silver grade is 4080g / t, the recovery rate is 52.63%, and the yield is 43.73%; it can be seen that compared with the original concentrate grade, there is a significant improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 APG dosage-silver recovery rate-silver grade curve of a process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to the present invention;

[0029] Figure 2 A graph showing the MIBC dosage-silver recovery rate-silver grade of a process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to the present invention;

[0030] Figure 3 The figure shows the dosage of MIBC sodium sulfide and the recovery rate-silver grade curve of a process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother in the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] A process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother, comprising the following steps:

[0033] Step 1: Wash the zinc leaching slag silver concentrate with a silver grade of ≥3000g / t and dry it in an electric constant temperature blast drying oven at a drying temperature of 70°C for a drying time of 2 hours, sieve it with a standard vibrating screen, pass it through a 200-mesh sieve with a pore size of 75μm, then take 15g of the ore sample for ultrasonic treatment at an ultrasonic power of 150W, an ultrasonic frequency of 40kHz, and an ultrasonic time of 2 minutes, and add deionized water to adjust the slurry concentration to a mass fraction of 15%-16%;

[0034] Step 2: first add 50-1000g / t of collector butylamine black medicine and stir for 3 minutes; then add a foaming agent, which is APG alkyl glycoside or MIBC methyl isobutyl carbinol, wherein the amount of APG added is 10-80g / t, the pH is adjusted to 6.5-8.5 or the amount of MIBC added is 10-50g / t, the pH is adjusted to 7.0-9.0, the stirring time is 1 minute, and the stirring speed is 800rpm; finally, sodium sulfide, an inhibitor, is added in an amount of 100g / t-500g / t;

[0035] Step 3: Use XFGII5-35 hanging tank flotation machine (specification 80ml, impeller speed 2350rpm) for aeration flotation, the aeration volume is 0.2m 3 / h, the inflation pressure is 0.05MPa and the flotation time is 3 minutes.

[0036] The operation steps are as follows: after the slurry is injected into the flotation tank, collectors, inhibitors and frothers are added in sequence; then the scraping frequency is 10 times / minute, and the concentrate and tailings are collected, dried, weighed and measured respectively.

[0037] Silver grade was determined using a Thermo Scientific Niton XL3t960 handheld X-ray fluorescence analyzer (XRF) with a detection limit of 5 ppm and a repeatability error of ±1%.

[0038] The specific operations are as follows:

[0039] 1. Grind the flotation concentrate and tailings samples to less than 200 mesh and press them into discs with a diameter of 30 mm;

[0040] 2. Turn on the device, select 'precious metal mode', and set the X-ray tube voltage to 50kV and current to 200μA;

[0041] 3. The probe is vertically aligned with the sample surface, the distance is ≤5mm, and the detection time is 10 seconds;

[0042] 4. The instrument automatically outputs the silver content (g / t). Each group of samples is tested three times and the average value is taken.

[0043] Then perform data verification:

[0044] To ensure the detection accuracy, 10% of the samples were randomly selected for comparative verification using inductively coupled plasma optical emission spectroscopy (ICP-OES, model PerkinElmer Optima 8300). The results showed that the silver content deviation between XRF and ICP-OES was ≤2.5% (relative error), which met the experimental accuracy requirements.

[0045] Only single roughing: no need for sweeping or fine selection, simplifying the process.

[0046] Embodiment 1:

[0047] Experiment on optimizing dosage of butyl ammonium black medicine

[0048] Experimental conditions: fixed ore sample dosage of 15g, ultrasonic cleaning machine, ultrasonic power of 300W, ultrasonic frequency of 40kHz, ultrasonic time of 2 minutes, adjusted slurry concentration mass fraction of 15%, flotation time of 3 minutes. The experimental research data on the effect of the dosage of butylamine black medicine on the flotation index of silver concentrate are shown in Table 1;

[0049] Table 1 Effect of the dosage of butylamine black medicine on the flotation index of silver concentrate

[0050]

[0051] As shown in Table 1, when the dosage of butylamine is 200g / t, the silver recovery rate is the highest, which can reach 48.11%, the concentrate grade is 4225g / t, and the yield is 38.60%.

[0052] Embodiment 2:

[0053] Comparative experiment between APG and MIBC

[0054] Experimental conditions: fixed ore sample dosage of 15g, ultrasonic cleaning machine, ultrasonic power of 300W, ultrasonic frequency of 40kHz, ultrasonic time of 2 minutes, slurry concentration adjusted to 15% by mass, butyl ammonium black medicine addition amount of 200g / t, stirring time of 3 minutes, frother reaction time of 1 minute, scraping time of 3 minutes.

[0055] The results are shown in Table 2;

[0056] Table 2 Comparative experiment of APG and MIBC on silver concentrate

[0057]

[0058] As can be seen from Table 2, APG significantly improves the silver grade by +25% at a low dosage of 20 g / t, but the recovery rate is lower than that of MIBC; MIBC requires a higher dosage of 30 g / t to achieve a high recovery rate.

[0059] Table 3 Experimental study on the effect of MIBC dosage on silver concentrate flotation index

[0060]

[0061] As can be seen from Table 3, when the dosage of MIBC is 30 g / t, the silver grade is the highest, which can reach 4080 g / t, the recovery rate can reach 52.63%, and the yield can reach 43.73%.

[0062] Table 4 Experimental study on the effect of APG dosage on the flotation index of silver concentrate

[0063]

[0064] It can be seen from Table 4 that when the dosage of APG is 20 g / t, the silver grade is the highest, which can reach 4240 g / t, the recovery rate can reach 36.18%, and the yield can reach 28.93%.

[0065] Embodiment 3:

[0066] Sodium sulfide inhibition test

[0067] Experimental conditions: the addition amount of butyl ammonium black medicine is 200g / t, the addition amount of MIBC is 30g / t, and the flotation time is 3 minutes. The experimental research data on the effect of the dosage of Na2S on the flotation index of silver concentrate are shown in Table 5;

[0068] Table 5 Experimental study on the effect of Na2S dosage on the flotation index of silver concentrate

[0069]

[0070]

[0071] As shown in Table 5, excessive Na2S, when the addition amount of Na2S is ≥200g / t, will cause a sharp drop in the silver recovery rate. When the dosage of Na2S is 200g / t, the silver recovery rate drops sharply to 32.88%. The optimal dosage of Na2S is 100-200g / t.

[0072] The experimental best drug control results are shown in Table 6;

[0073] Table 6 Experimental best drug control results

[0074]

[0075] It can be seen from Table 6 that when 200g / t of black powder + 20g / t of APG are added, the silver grade is the highest, which can reach 4240g / t; when 200g / t of black powder + 30g / t of MIBC are added, the silver recovery rate is the highest, which can reach 52.63%, and the silver yield is also the highest, which can reach 43.73%; when 200g / t of black powder + 30g / t of MIBC + 200g / t of Na2S are added, the silver grade, silver recovery rate and silver yield all drop sharply.

[0076] in, Figure 1 This is the APG dosage-silver recovery rate-silver grade curve. Figure 2 is the MIBC dosage-silver recovery-silver grade curve, Figure 1 and Figure 2 It can be seen that when APG is 20g / t, it selectively adsorbs silver minerals (compared with the traditional foaming agent MIBC which requires 30g / t). When APG is 20g / t, the silver grade reaches 4240g / t (peak value) and the recovery rate is 36.18%. Excessive APG (>50g / t) causes foam overload and tailings are entrained in the concentrate.

[0077] Figure 3 is the sodium sulfide dosage-silver recovery rate-silver grade curve, Figure 3 It can be seen that when 100g / t≤Na2S≤200g / t, the recovery rate is stable ≥40%; when Na2S>200g / t, due to excessive inhibition of silver sulfide minerals, the recovery rate plummets to 32.88%. The sudden drop in the recovery rate when Na2S is 200g / t limits the safe dosage range to 100-200g / t.

[0078] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for improving the grade of zinc leaching slag silver concentrate by coupling coal preparation frother with single roughing, characterized in that: The following steps are involved: Step 1: Wash and dry the silver concentrate slurry of zinc leaching slag with a silver grade of ≥3000g / t, sieve, then take a sample for ultrasonic treatment, and add deionized water to adjust the slurry concentration; Step 2: first add the collector butylamine black medicine and stir; then add the foaming agent and stir; finally add the inhibitor; Step 3: Perform aeration flotation.

2. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In the step 1, an electric constant temperature blast drying oven is used for drying, the drying temperature is 70° C., and the drying time is 2 hours.

3. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In the step 1, a standard vibrating screen is used for screening, and the product is passed through a 200-mesh screen with a pore size of 75 μm.

4. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In the step 1, the ultrasonic power is 150 W, the ultrasonic frequency is 40 kHz, and the ultrasonic time is 2 minutes.

5. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In the step 1, 15 g of ore sample is taken and the slurry concentration is adjusted to a mass fraction of 15%-16%.

6. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In the step 2, the amount of butylamine black medicine added is 50-1000g / t, and stirring is carried out for 3 minutes.

7. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In step 2, the foaming agent is coal preparation foaming agent APG alkyl glycoside or MIBC methyl isobutyl carbinol, wherein the addition amount of APG is 10-80 g / t or the addition amount of MIBC is 10-50 g / t, the stirring time is 1 minute, and the stirring speed is 800 rpm.

8. A process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 7, characterized in that: When the foaming agent is APG, the pH is adjusted to 6.5-8.5, and when the foaming agent is MIBC, the pH is adjusted to 7.0-9.

0.

9. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In step 2, the inhibitor is sodium sulfide, and the addition amount is 100g / t-500g / t.

10. The process for improving the grade of zinc leaching slag silver concentrate by single roughing with a coupled coal preparation frother according to claim 1, characterized in that: In step 3, the inflation volume is 0.2m 3 / h, the inflation pressure is 0.05MPa and the flotation time is 3 minutes.

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