Device for reducing metal loss during evaporation of gold electrolyte

Abstract

The utility model discloses a device for reducing evaporation metal loss of gold electrolyte, which comprises at least two stages of surface air coolers, a condensation recovery pipe is longitudinally arranged in a shell of each surface air cooler as a pipe pass flow channel, and a space on the side part of the condensation recovery pipe in the shell is used as a shell pass flow channel. And a demister communicated with the upper end of the condensation recovery pipe in the surface air cooler shell is mounted in the surface air cooler shell. And the demister in the front-stage surface air cooler shell is communicated with the lower end of the condensation recovery pipe in the adjacent rear-stage surface air cooler shell. The lower end of the condensation recovery pipe in the shell of the first-stage surface air cooler is communicated with the liquid collection box, and the upper end of the demister in the shell of the last-stage surface air cooler is communicated with the acid gas discharge pipe. The cold water inlet pipe is communicated with the water inlet of the shell pass flow channel; the cold water return pipe is communicated with the water outlet of the shell pass flow channel. The gold-containing acid gas moves upwards along the inner cavity of the condensation recovery pipe, the condensed and liquefied gold-containing electrolyte flows back to the liquid collection box downwards along the inner wall of the condensation recovery pipe under the action of gravity, precious metal recovery is achieved through liquid-phase self-flowing, and continuous production is achieved.

Description

Technical Field

[0001] The utility model relates to a device for reducing the evaporation metal loss of gold electrolyte. Background Art

[0002] Gold electrolytic refining is one of the most widely used production processes in the field of gold purification. At present, in order to increase the electrolysis speed and shorten the refining cycle, gold electrolytic refining mostly uses high current density, so it is required to control the temperature of the gold refining electrolyte at a high level, generally ranging from 50 to 80°C. The increase in temperature accelerates the evaporation of the gold electrolyte. Since the acid gas condensate evaporated from the gold electrolyte contains several grams, dozens of grams or even tens of grams of gold per liter, it is sucked into the alkaline liquid circulation absorption tower through the exhaust duct, causing the gold content of the circulating liquid in the absorption tower to continue to increase. Although it is replaced regularly, the mist droplets formed by the spraying of the gold-containing circulating liquid are discharged into the atmosphere of the outer chamber with the air flow, causing a certain loss of gold, thereby reducing the gold recovery rate and causing economic losses to the company.

[0003] For example, a domestic precious metal company uses a hydrochloric acid system for gold electrolytic refining and purification. Since the temperature needs to be controlled at 70-80°C, the amount of electrolyte evaporation is large, and the gold content in the evaporated liquid is generally 1.5-2.0g / L. It enters the absorption tower with the acid gas, and is absorbed by the three-stage alkali solution circulation spray and then blown by the fan.

[0004] Drained to the outside. Usually the first-level absorption tower contains about 100-120g / m³ of gold; the second-level absorption tower contains about 50-70g / m³ of gold; the third-level absorption tower contains about 20-50g / m³ of gold. In normal electrolysis, each absorption tower needs to replenish 220-300 liters of water for 8 hours / shift. Based on the above process characteristics, the evaporated electrolyte causes a certain amount of metal loss, which is not conducive to metal balance work. In addition, if the circulating liquid of the absorption tower is frequently replaced, the amount of waste liquid will increase and the production cost will increase.

[0005] The Chinese utility model with the authorization announcement number CN209854222U discloses a "precious metal dissolution waste gas gold liquid recovery device and precious metal dissolution system", which achieves the purpose of recovering precious metals through condensation, and is beneficial to solving the problem of gold loss caused by the discharge of gold-containing circulating liquid with waste gas. However, it still has the problem that the structure of the condensation tank is not reasonable enough, and it is difficult to achieve continuity and the condensation recovery effect is poor. Specifically, according to the description in paragraph

[0030] , when all the waste gas generated is processed, the nozzle in the condensation tank is opened, and the flushing liquid sprayed from the nozzle flushes the metal on the surface of the condensation pipeline into the precious metal dissolution reactor through the exhaust port. In other words, the precious metal to be recovered is deposited on the outer surface of the condensation pipeline. After completing a waste gas treatment process (that is, when all the waste gas generated is processed), the gas-liquid separation operation is stopped, and the precious metal is flushed and recovered. Therefore, the recovery device disclosed in the patent technology is actually intermittent work, and there is a defect of low recovery efficiency.

[0006] On the other hand, the exhaust gas condensation process only occurs in the condenser area. Under the suction of the vacuum pump, the exhaust gas is in a flowing state, the contact path length and heat exchange time with the condenser are short, the probability of gold-containing acid gas penetration is high, and the condensation recovery effect is difficult to be satisfactory. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a device for reducing the evaporation metal loss of gold electrolyte, realize rapid and efficient condensation of acid gas, and achieve the purpose of continuous and efficient recovery of gold-containing electrolyte.

[0008] The technical solution of the utility model is as follows:

[0009] A device for reducing the evaporation metal loss of gold electrolyte comprises at least two stages of coolers, the cooler comprising a cooler shell, a condensation recovery pipe is longitudinally arranged in the cooler shell as a heat exchange tube-side flow channel, and the space on the side of the condensation recovery pipe in the cooler shell serves as a shell-side flow channel for heat exchange; a demister is installed in the cooler shell and communicates with the upper end of the condensation recovery pipe in the cooler shell; the demister in the previous stage cooler shell is connected to the lower end of the condensation recovery pipe in the adjacent next stage cooler shell; the device also comprises an acid gas discharge pipe and a liquid collecting box connected to the gold electrolytic cell through a first air duct; the lower end of the condensation recovery pipe in the first stage cooler shell is connected to the liquid collecting box, and the upper end of the demister in the last stage cooler shell is connected to the acid gas discharge pipe; the device also comprises a cold water inlet pipe connected to the water inlet of the shell-side flow channel and installed with a first valve, and a cold water return pipe connected to the water outlet of the shell-side flow channel and installed with a second valve.

[0010] Preferably, the device further comprises an expansion pipe connected to the lower end of the first-stage surface cooler and communicating with the condensation recovery pipe in the shell of the first-stage surface cooler; the lower end of the expansion pipe is connected to the liquid collecting tank via a second air duct.

[0011] Preferably, the device further comprises a shrink tube connected to the upper end of the final stage surface cooler and communicating with a demister in the shell of the final stage surface cooler; the outer end of the shrink tube is connected to the acid gas discharge pipe.

[0012] Preferably, the device further comprises a first liquid discharge pipe equipped with a third valve, one end of the first liquid discharge pipe is connected to the liquid collecting tank, and the other end is connected to a liquid pump, and the liquid outlet end of the liquid pump is connected to a second liquid discharge pipe.

[0013] Preferably, the demister comprises a supporting device and a corrugated plate fixedly mounted on the supporting device.

[0014] Preferably, the outer wall of the surface cooler shell, the outer wall of the cold water inlet pipe and the outer wall of the cold water return pipe are all provided with a thermal insulation layer.

[0015] Preferably, the liquid collecting tank is provided with an observation window and a pressure balancing valve.

[0016] Compared with the prior art, the utility model has the following positive effects:

[0017] First, in the utility model, the gold-containing acid gas goes up along the inner cavity of the condensation recovery pipe, and the condensed and liquefied gold-containing electrolyte flows down along the inner wall of the condensation recovery pipe to the liquid collection tank. It is not necessary to set up a flushing pipeline, but the precious metal recovery can be achieved by relying on the liquid self-flow. The probability of the evaporated gold-containing liquid in the electrolytic cell being carried into the absorption tower with the air flow is reduced, thereby reducing the metal loss caused by the evaporation of the circulating liquid in the absorption tower. Continuous production is achieved and the efficiency of factory operation is improved.

[0018] Second, in the utility model, the gold-containing acid gas flows through the condensation recovery pipe and then flows through the demister. The main function of the demister is to have turbulence and droplet capture effects, and to extend the gas-liquid separation path. The acid gas that has condensed into small droplets in the condensation recovery pipe further condenses and refluxes after passing through the demister, thereby further enhancing the gas-liquid separation effect. Specifically, when the acid gas that has condensed into small droplets in the condensation recovery pipe flows through the demister at a certain speed, the mist collides with the corrugated plate, and the small droplets gradually gather into large droplets. When the gravity of the large droplets exceeds the combined force of the rising power of the gas and the surface tension of the liquid, they are separated from the surface of the corrugated plate and fall. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the utility model.

[0020] Figure 2 yes Figure 1AA cross-sectional view of .

[0021] In the figure, 1, liquid collecting tank, 2, first air duct, 3, cold water inlet pipe, 4, first valve, 5, insulation layer, 6, acid gas discharge pipe, 7, contraction pipe, 8, secondary surface cooler, 9, secondary demister, 10, cold water return pipe, 11, second valve, 12, first stage demister, 13, first stage surface cooler, 14, condensate recovery pipe, 15, expansion pipe, 16, second air duct, 17, first liquid discharge pipe, 18, third valve, 19, liquid pump, 20, second liquid discharge pipe. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the embodiments and drawings.

[0023] like Figure 1 and Figure 2 The device for reducing the evaporation metal loss of gold electrolyte of the utility model comprises a liquid collecting box 1 connected to the gold electrolytic cell through a first air duct 2. The embodiment also comprises a second air duct 16, an expansion tube 15, a primary surface cooler 13, a secondary surface cooler 8 and a shrink tube 7 which are fixedly connected in sequence from bottom to top, and an acid gas discharge pipe 6 is connected to the upper end of the shrink tube 7. The lower end of the second air duct 16 is connected to the liquid collecting box 1. The acid gas discharge pipe 6 is used to connect the absorption tower.

[0024] The first-stage cooler 13 and the secondary cooler 8 both include a cooler shell, in which a group of condensation recovery pipes 14 are longitudinally arranged as heat exchange tube-side flow channels, and the space on the side of the condensation recovery pipes 14 in the cooler shell serves as the shell-side flow channel for heat exchange. A first-stage defogger 12 is installed above the condensation recovery pipes 14 in the shell of the first-stage cooler 13, and a secondary defogger 9 is installed above the condensation recovery pipes 14 in the shell of the secondary cooler 8. Specifically, the upper and lower ends of the condensation recovery pipe 14 are respectively connected with end plates in the form of orifice plates. The condensation recovery pipe 14 in the shell of the first-stage cooler 13 is connected to the expansion pipe 15 through the hole on its lower end plate, and is connected to the first-stage defogger 12 through the hole on its upper end plate. The condensation recovery pipe 14 in the shell of the secondary cooler 8 is connected to the first-stage defogger 12 through the hole on its lower end plate, and is connected to the secondary defogger 9 through the hole on its upper end plate. The shell-side flow channel is located between the end plates at the upper and lower ends of the condensation recovery pipe 14 .

[0025] From bottom to top, the liquid collecting tank 1, the second air duct 16, the expansion pipe 15, the condensate recovery pipe 14 in the first-stage surface cooler 13, the first-stage demister 12, the condensate recovery pipe 14 in the secondary surface cooler 8, the secondary demister 9, the contraction pipe 7 and the acid gas discharge pipe 6 are connected in sequence.

[0026] This embodiment further comprises a cold water inlet pipe 3 connected to the water inlet of the shell-side flow channel and installed with a first valve 4, and a cold water return pipe 10 connected to the water outlet of the shell-side flow channel and installed with a second valve 11.

[0027] This embodiment further comprises a first liquid discharge pipe 17 equipped with a third valve 18 , one end of the first liquid discharge pipe 17 is connected to the liquid collecting box 1 , and the other end is connected to a liquid pump 19 , and the liquid outlet end of the liquid pump 19 is connected to a second liquid discharge pipe 20 .

[0028] The first-stage demister 12 and the secondary demister 9 have the same structure. They both include a supporting device and a plurality of corrugated plates fixedly mounted on the supporting device. There is a channel between adjacent corrugated plates to allow the acid gas to flow through. The demister can be connected to the lower end plate of the condensation recovery pipe 14 through a bracket, or it can be fixed to the inner wall of the surface cooler shell. The corrugated plates are generally made of polypropylene. The utility model preferably uses a baffle demister, such as the "C-type desulfurization tower baffle ridge demister" produced and sold by Hebei Longqin Technology Development Co., Ltd.

[0029] Among them, the upper end of the second air duct 16 is connected to the lower end of the expansion tube 15 through a flange, the inner ends of the cold water inlet pipe 3 and the cold water return pipe 10 are respectively connected to the surface cooler shell through flanges, the upper end of the shrink tube 7 is connected to the acid gas discharge pipe 6 through a flange, and the lower end of the shrink tube 7 is connected to the upper end of the surface cooler shell of the secondary surface cooler 8 through a flange.

[0030] Furthermore, the outer side walls of the cooler shells of the primary cooler 13 and the secondary cooler 8 and the outer side walls of the cold water inlet pipe 3 and the cold water return pipe 10 are all provided with a heat insulation layer 5 .

[0031] Furthermore, the liquid collecting tank 1 is provided with an observation window and a pressure balancing valve (the observation window and the pressure balancing valve are omitted in the drawings).

[0032] The following examples illustrate the working process of the present utility model.

[0033] The acid gas in the liquid collecting tank 1 goes up along the inner cavity of the condensation recovery pipe 14, and the condensed and liquefied gold-containing electrolyte flows downward along the inner wall of the condensation recovery pipe 14 back to the liquid collecting tank 1. When the liquid accumulation in the liquid collecting tank 1 reaches a certain level, the third valve 18 and the liquid pump 19 are opened to discharge the system.

[0034] The cold water produced by the refrigeration machine installed in the equipment room (the equipment room and the electrolysis site belong to different rooms to achieve mutual isolation) is sent to the shell-side flow channel through the cold water inlet pipe 3 to refrigerate the high-temperature steam of the gold-containing electrolyte, and returns to the refrigeration machine through the cold water return pipe 10 after completing a heat exchange.

[0035] The beneficial effects of the present invention are further described below in combination with the economic benefits brought by the present invention.

[0036] Since the above-mentioned precious metals company put the utility model into trial use, the effect has been remarkable, and the gold loss and wastewater volume have been reduced to varying degrees.

[0037] Before the condensation recovery device was used, the gold content of the circulating liquid in the first-stage electrolysis absorption tower was stable at about 100-120g / m³; the gold content of the circulating liquid in the second-stage absorption tower was stable at about 50-70g / m³; and the gold content of the circulating liquid in the third-stage absorption tower was stable at about 30-50g / m³.

[0038] After the installation of the utility model and after one year of trial operation, the gold content of the circulating liquid in the first-stage absorption tower has dropped to about 50-60g / m³; the gold content of the circulating liquid in the second-stage absorption tower has dropped to about 20-30g / m³; the gold content of the circulating liquid in the third-stage absorption tower has dropped to about 5-10g / m³. The waste gas is directly discharged to the outside after being absorbed by the circulating liquid in the third-stage absorption tower. Before the condensation recovery device is used, the gold content of the circulating liquid in the third-stage absorption tower is temporarily 40g / m³; after the installation of the utility model, the gold content of the circulating liquid in the third-stage absorption tower is temporarily 8g / m³; the spraying of the circulating liquid in the third-stage absorption tower is calculated by reducing 260 liters every eight hours; the workshop has two shifts every day, and the absorption tower runs for 16 hours every day; the annual operation time of gold electrolytic refining is calculated as 200 days, which can reduce the loss of gold: (40-8)×0.26×2×200=3328 (g). If the gold price is 470 yuan / g, the benefit of reducing gold loss is: 470×3328=1.5642 million yuan.

[0039] According to the calculation of the trial operation, after the installation of the utility model, about 4 to 5 m³ of liquid evaporated from the electrolyte can be cooled and recovered each year. This liquid contains about 8 to 10% hydrochloric acid and can be reused as replenishment water for the evaporation of the electrolyte. At the same time, the replacement of the circulating liquid of the three electrolytic absorption towers is reduced twice a year, and about 6 m³ of waste water generated by the absorption tower is saved each time, and the output of waste water is reduced by about 12 m³ throughout the year. The cost of waste water transportation and treatment is 5,000 yuan / t, and each cubic meter of waste water is calculated as 1 t. The annual saving in waste water treatment costs is: 5,000×12=60,000 yuan.

[0040] The investment in the refrigeration system is about 75,000 yuan, and the investment in this utility model is about 36,000 yuan (two in total, 18,000 yuan / unit). The total is about 111,000 yuan, and the depreciation is calculated based on six years, with an annual depreciation of about 18,500 yuan. The electrolytic evaporation condensation system consumes about 10kw / h of electricity, 1.36 yuan / kw.h, and runs two shifts for fifteen hours a day. The annual operating cost of the electrolytic evaporation condensation system is about: 10×15×1.36×200=40,800 yuan. The economic benefits increased by the use of this utility model are: 156.42+6-1.85-4.08=156.49 million yuan.

Claims

1. A device for reducing the evaporation metal loss of gold electrolyte, comprising at least two stages of surface coolers, the surface coolers comprising a surface cooler housing, characterized in that: A condensate recovery pipe (14) is longitudinally arranged in the cooler shell as a heat exchange pipe-side flow channel, and the space on the side of the condensate recovery pipe (14) in the cooler shell serves as a shell-side flow channel for heat exchange; a demister is installed in the cooler shell and communicates with the upper end of the condensate recovery pipe (14) in the cooler shell; the demister in the previous cooler shell is connected to the lower end of the condensate recovery pipe (14) in the adjacent next cooler shell; the device also includes an acid gas discharge pipe (6) and a liquid collecting tank (1) connected to the gold electrolytic cell through a first air duct (2); the lower end of the condensate recovery pipe (14) in the first cooler shell is connected to the liquid collecting tank (1), and the upper end of the demister in the last cooler shell is connected to the acid gas discharge pipe (6); the device also includes a cold water inlet pipe (3) connected to the water inlet of the shell-side flow channel and installed with a first valve (4) and a cold water return pipe (10) connected to the water outlet of the shell-side flow channel and installed with a second valve (11).

2. The device for reducing the evaporation metal loss of gold electrolyte according to claim 1, characterized in that: The device also includes an expansion pipe (15) connected to the lower end of the first-stage surface cooler and communicating with a condensation recovery pipe (14) in the shell of the first-stage surface cooler; the lower end of the expansion pipe (15) is connected to the liquid collecting tank (1) via a second air duct (16).

3. The device for reducing the evaporation metal loss of gold electrolyte according to claim 1, characterized in that: The device further comprises a shrink tube (7) connected to the upper end of the final stage surface cooler and communicating with a demister in the shell of the final stage surface cooler; the outer end of the shrink tube (7) is connected to the acid gas discharge pipe (6).

4. The device for reducing the evaporation metal loss of gold electrolyte according to claim 1, characterized in that: The device further comprises a first liquid discharge pipe (17) equipped with a third valve (18); one end of the first liquid discharge pipe (17) is connected to the liquid collecting tank (1), and the other end is connected to a liquid pump (19); the liquid outlet end of the liquid pump (19) is connected to a second liquid discharge pipe (20).

5. The device for reducing the evaporation metal loss of gold electrolyte according to any one of claims 1 to 4, characterized in that: The demister comprises a supporting device and a corrugated plate fixedly mounted on the supporting device.

6. The device for reducing the evaporation metal loss of gold electrolyte according to any one of claims 1 to 4, characterized in that: The outer wall of the surface cooler shell, the outer wall of the cold water inlet pipe (3) and the outer wall of the cold water return pipe (10) are all provided with a thermal insulation layer (5).

7. The device for reducing the evaporation metal loss of gold electrolyte according to any one of claims 1 to 4, characterized in that: The liquid collecting tank (1) is provided with an observation window and a pressure balancing valve.

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