CN103060559A - Microfluid extraction method for extracting and separating In, Fe and Zn - Google Patents

Abstract

The invention provides a microfluidic extraction method for extracting and separating In, Fe, and Zn. The sulfuric acid system solution containing indium, iron, and zinc is used as the water phase, and the P204 extraction agent diluted with solvent oil is used as the organic phase. In the pump, the outlet end of the flow pump is connected to the inlet of the microreactor; at the same time, the two-phase laminar flow interface formed in the microchannel is observed through an optical microscope, and the two phases start to separate when they flow in parallel to the Y-shaped fork at the outlet of the microchannel, from Each outlet flows out of the microreactor, and the two phases are collected separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase, realizing the separation of indium from iron and zinc. The extraction rate of In can reach more than 90%, while Fe and Zn ions are not extracted at all, and there is no emulsification phenomenon, the reaction time is greatly shortened, the amount and consumption of extraction agent can be reduced, and the conditions are controllable and safe. High resistance, to avoid the extraction of organic solvents exposed to the air.

Description

A microfluidic extraction method for extracting and separating In, Fe, and Zn

technical field

The invention relates to a method for extracting valuable metals by using a microreactor system, which belongs to the field of microfluid technology.

Background technique

The extraction and separation process of hydrometallurgy can directly separate and purify a variety of metal ions from the solution, avoiding the waste residue generated during the separation process such as precipitation, crystallization or reduction, and the numerous processes from solution to slag and then to solution. key means of purification. However, there are still some key problems that need to be solved in the traditional extraction process:

a. Large consumption of extractant

Due to the relatively long extraction and stripping time, multi-stage or even more than ten stages of extraction are often required. In order to meet the requirements of extraction and mass transfer, a large amount of extractant is used. In addition, the extractant has a large contact area with the air, is greatly affected by the ambient temperature, and volatilizes severely. The shear force during the high-energy stirring process may destroy the molecular structure of the extractant and cause problems such as temperature rise.

b. Serious co-extraction and low extraction efficiency

Under strong mixing conditions, the co-extraction of main metal ions and impurity metal ions is severe, and the selectivity of extraction is poor, resulting in the need for multi-stage washing and stripping after extraction. For example, in the process of extracting and separating Ni and Co with P204, due to the co-extraction of Fe, Zn, Mn and Cu during the extraction of Co, the entire extraction stage can reach more than 18 levels. The co-extraction problem of Zn, Sb, Bi and Cl, etc. makes the whole extraction stages reach more than 14 stages. This greatly increases the investment cost and reduces the extraction efficiency.

c, prone to emulsification

Regarding the mechanism of emulsification during the extraction of indium, in-depth research has been carried out at home and abroad, and many preventive measures have been proposed. But so far, the emulsification phenomenon cannot be well avoided. The reason is that for complex solution systems with particles, certain metal ions, or surfactants, the high-energy mixing of conventional extraction makes the extraction process very sufficient and rapid, but in the phase separation process, due to Stable particles (such as particle colloids) are adsorbed on the liquid-liquid interface of emulsion particles to become a stable protective layer, making the coalescence rate of two-phase droplets very slow or even completely stopped, and removing a particle from the interface The energy required is great. This is the root cause of difficulty in demulsification and the need to input a large amount of energy.

d. Big fire hazard

Since the extraction process takes a long time, it is necessary to build a large volume of stirring tank and clarification tank, and the entire extraction process will occupy a large area. Moreover, a large area of the organic phase is exposed to the air, so that the fire hazard is relatively large. In recent years, there have been many fire accidents in the extraction workshops of large-scale smelters in my country, and frequent fire accidents in the extraction process of some small smelters.

Therefore, these limitations of conventional extraction need to be solved urgently, and the development of airtight and efficient extraction equipment is the key to solve this problem.

Using the characteristics of high efficiency, low consumption and safety of the microreactor system to transform the low-efficiency and high-consumption unit processes of the traditional metallurgical industry such as extraction, heat exchange and mixing, it is possible to develop new energy-saving processes, thereby promoting the development of the metallurgical industry Industrial upgrading.

Since the physical size of the effective channel or chamber of the microreactor is reduced to the micron or even nanometer level, the gradient of fluid physical quantities such as temperature, pressure, concentration and density increases sharply, resulting in a great increase in the driving force of heat and mass transfer, which can make The heat transfer coefficient increases by an order of magnitude while the mass transfer reaction time decreases by an order of magnitude. The resulting advantages are also manifested in: due to the increase of reaction speed, the reaction equipment and reaction system can be greatly reduced, which greatly improves the safety of the reaction process, greatly saves land investment, and greatly reduces material consumption; for raw materials, reaction processes or Toxic reactions in the product can avoid the risk of transportation of toxic and harmful raw materials by adopting small-scale distributed production methods in different regions; its processing capacity can be improved by increasing the number of functional units (Numbering-up) instead of step by step Level amplification reaction equipment. At present, the advanced micro-manufacturing technology is promoting the rapid development of micro-reactors. The focus in this field is largely on the study of diffusion and mass transfer of immiscible liquid-liquid two-phase extraction separation.

In the field of microfluidics, solvent extraction is very efficient because of its high specific surface area and short diffusion distance. It is beneficial to reduce the diffusion path length and increase the mass transfer rate of the two-phase interface, thereby increasing the chemical reaction rate. In addition, phase mass transfer under laminar flow control can avoid emulsification. Through the "number superposition" Numbering-up (such as parallel processing) technology provides a new possibility for the increase of the output of the microfluidic process. This also enables batch operations (mixing/reaction/separation) to be performed continuously. Therefore, under the microchemical system, the goals of simplifying the process flow, preventing emulsification and shortening the reaction time can be achieved at the same time.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of traditional solvent extraction of indium, such as low extraction efficiency, easy emulsification of the solution, difficulty in separating indium from impurities such as iron and zinc, serious environmental pollution, and high risk, and provides a method for extracting and separating In and Fe , The microfluidic extraction method of Zn is a new method with high efficiency, safety, no pollution and high separation rate.

The present invention is realized through the following technical solutions: a microfluidic extraction method for extracting and separating In, Fe, and Zn, through the following steps:

(1) The sulfuric acid system solution containing indium, iron, and zinc is used as the water phase, and the P204 extractant diluted with solvent oil is used as the organic phase to pass into two flow pumps respectively, and the outlet end of the flow pump is connected to the inlet of the microreactor;

(2) Turn on the flow pump of the organic phase first. After the organic phase enters the microchannel of the microreactor, set the flow rate of the organic phase at 0.65 times and turn on the flow pump of the water phase. Phase laminar flow phase interface (observation with a microscope can see that the water phase and the organic phase are moving in parallel in the microchannel, and the two-phase laminar flow phase interface is the contact surface between the water phase and the organic phase), during which the flow of the two phases is adjusted , so that the two phases flow in parallel;

(3) When the two phases flow to the Y-shaped fork at the outlet of the microchannel, they begin to separate, and flow out of the microreactor from their respective outlets, and collect the two phases separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase , realized the separation of indium, iron and zinc.

The sulfuric acid system solution containing indium, iron and zinc is the leaching solution in the zinc hydrometallurgy process.

Described solvent oil is conventional solvent oil, such as No. 260 solvent oil.

The characteristic size of the microchannel is 160-800 μm (inner diameter), and the length is 80-480 mm.

The contact time of the two phases in the microchannel is 0.01-10s.

Invention principle: Due to the ratio of the area of the two-phase interface in the microreactor to the mass transfer depth of the two phases, the concentration gradient of the target element in the two phases is very large, resulting in a greatly improved extraction driving force, and the mass transfer efficiency is often an order of magnitude higher than that of traditional operations. Therefore, the immiscible two phases can undergo rapid mass transfer in the microchannel under the condition of short-time laminar flow contact. It is characterized by strengthening the metallurgical operation unit process, improving efficiency and reducing energy consumption.

Microfluidic technology is a technology for controlling, manipulating and detecting complex fluids at a microscopic scale. It is a new interdisciplinary subject developed on the basis of microchemical engineering, micromechanics, bioengineering and nanotechnology. The rapid development of microfluidic technology in recent years has caused revolutionary impacts in the fields of chemistry, medicine and life sciences. At present, in the field of chemistry and chemical engineering, such as gas treatment, chemical synthesis and particle synthesis, microfluidic technology has been able to achieve an annual production capacity of several tons. Therefore, the application of microfluidic technology in the field of hydrometallurgy may play an important role in improving the emulsification phenomenon in the hydrometallurgical solvent extraction process, reducing the amount of extractant and improving the safety of extraction operations.

The present invention uses microfluidic technology to keep the two-phase liquid in the microchannel to maintain laminar flow, and quickly separates through the Y-shaped outlet. The extraction rate of In can reach more than 90%, while Fe and Zn ions are not extracted at all, and there is no Emulsification phenomenon, thereby avoiding a series of problems in the traditional extraction of solutions containing In, Fe and Zn. It has the following effects and advantages:

1. The present invention adopts microfluidic solvent extraction technology to recover In metal in the zinc hydrometallurgy leaching solution, the recovery efficiency is high, and the time required for the reaction is greatly shortened.

2. Since the extraction process of the present invention is short in time, the amount and consumption of the extractant can be greatly reduced by increasing the number of cycles.

3. The present invention uses microfluidic laminar flow conditions for selective extraction, which can avoid emulsification during the extraction process.

4. The present invention enables efficient separation of In from impurity metals such as Fe and Zn, and the extraction selectivity is very superior.

5. The present invention ensures that the reaction is carried out in a closed system, the conditions are highly controllable, and the safety is high, avoiding the risk of volatilization and fire caused by the extraction of organic solvents exposed to the air.

Description of drawings

Fig. 1 is the device schematic diagram of microreactor of the present invention;

Figure 2 is a schematic cross-sectional view of the microchannel of Example 1.

Detailed ways

The present invention will be further described below by embodiment.

Example 1

(1) The sulfuric acid system solution containing 4.52g/L indium, iron, and zinc (leaching solution in the process of hydrometallurgy of zinc) is used as the water phase, and the P204 extraction agent diluted with No. 260 solvent oil (30% volume fraction P204+70 %volume fraction solvent oil) as the organic phase respectively into the two flow pumps, the outlet end of the flow pump is connected to the inlet of the microreactor;

(2) Turn on the organic phase flow pump first, and after the organic phase enters the microchannel of the microreactor (with a characteristic size of 160 μm and a length of 380 mm), set and turn on the water phase flow pump at 0.65 times the flow rate of the organic phase, and at the same time The two-phase laminar flow interface formed in the microchannel is observed through an optical microscope (observation with a microscope can see that the water phase and the organic phase are moving in parallel from left to right in the microchannel, and the two-phase laminar flow interface is the water phase and the organic phase. contact surface), during which the flow of the two phases is adjusted so that the two phases flow in parallel, and the contact time of the two phases in the microchannel is 1.49s;

(3) When the two phases flow to the Y-shaped fork at the outlet of the microchannel, they begin to separate, and flow out of the microreactor from their respective outlets, and collect the two phases separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase , realized the separation of indium, iron and zinc. The In extraction rate of 92.50% was detected, and the system had no emulsification phenomenon.

Example 2

(1) The sulfuric acid system solution containing 3.17g/L of indium, 3.42g/L of iron, and 52.82g/L of zinc (leaching solution in the process of hydrometallurgy of zinc) is used as the water phase, P204 extractant diluted with conventional solvent oil ( 30% volume fraction P204+70% volume fraction solvent oil) as the organic phase respectively passed into two flow pumps, and the outlet end of the flow pump was connected to the inlet of the microreactor;

(2) Turn on the flow pump of the organic phase first, and after the organic phase enters the microchannel of the microreactor (with a characteristic size of 200 μm and a length of 80 mm), set the flow rate of the organic phase to 0.65 times and turn on the flow pump of the water phase, and at the same time The two-phase laminar flow interface formed in the microchannel is observed through an optical microscope (observation with a microscope can see that the water phase and the organic phase are moving in parallel from left to right in the microchannel, and the two-phase laminar flow interface is the water phase and the organic phase. contact surface), during which the flow of the two phases is adjusted so that the two phases flow in parallel, and the contact time of the two phases in the microchannel is 0.69s;

(3) When the two phases flow to the Y-shaped fork at the outlet of the microchannel, they begin to separate, and flow out of the microreactor from their respective outlets, and collect the two phases separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase , realized the separation of indium, iron and zinc. It was detected that the extraction rate of In was 90.80%, while the extraction rates of Fe and Zn were both 0, and the system had no emulsification phenomenon.

Example 3

(1) The sulfuric acid system solution containing 4.12g/L indium, iron and zinc (leaching solution in the process of hydrometallurgy of zinc) is used as the water phase, and the P204 extractant diluted with conventional solvent oil is used as the organic phase to pass into two flow In the pump, the outlet end of the flow pump is connected to the inlet of the microreactor;

(2) Turn on the flow pump of the organic phase first, and after the organic phase enters the microchannel of the microreactor (the characteristic size is 800 μm, the length is 90 mm), then set and turn on the flow pump of the water phase at 0.65 times the flow rate of the organic phase, and at the same time The two-phase laminar flow interface formed in the microchannel is observed through an optical microscope (observation with a microscope can see that the water phase and the organic phase are moving in parallel from left to right in the microchannel, and the two-phase laminar flow interface is the water phase and the organic phase. contact surface), during which the flow of the two phases is adjusted so that the two phases flow in parallel, and the contact time of the two phases in the microchannel is 0.01s;

(3) When the two phases flow to the Y-shaped fork at the outlet of the microchannel, they begin to separate, and flow out of the microreactor from their respective outlets, and collect the two phases separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase , realized the separation of indium, iron and zinc. The In extraction rate of 92.10% was detected, and the system had no emulsification phenomenon.

Example 4

(1) The sulfuric acid system solution containing 3.92g/L indium, iron and zinc (leaching solution in the process of hydrometallurgy of zinc) is used as the water phase, and the P204 extractant diluted with No. 260 solvent oil is used as the organic phase to pass into two sets In the flow pump, the outlet of the flow pump is connected to the inlet of the microreactor;

(2) Turn on the organic phase flow pump first, wait for the organic phase to enter the microchannel of the microreactor (with a characteristic size of 700 μm and a length of 480 mm, then set and turn on the water phase flow pump at 0.65 times the flow rate of the organic phase, and simultaneously pass The two-phase laminar flow interface formed in the microchannel is observed by an optical microscope (the water phase and the organic phase can be seen to move in parallel in the microchannel when viewed from the top of the microscope, and the two-phase laminar flow interface is the contact between the water phase and the organic phase surface), during which the flow rate of the two phases is adjusted so that the two phases flow in parallel, and the contact time of the two phases in the microchannel is 10s;

(3) When the two phases flow to the Y-shaped fork at the outlet of the microchannel, they begin to separate, and flow out of the microreactor from their respective outlets, and collect the two phases separately. Indium is extracted into the organic phase, while iron and zinc remain in the water phase , realized the separation of indium, iron and zinc. The In extraction rate of 91.86% was detected, and the system had no emulsification phenomenon.

Claims (5)

1. the microfluid extracting process of an extracting and separating In and Fe, Zn is characterized in that through following each step:

The sulfuric acid system solution that (1) will contain indium, iron, zinc is as water, pass into respectively as organic phase in two flow pumps through the P204 extraction agent of solvent oil dilution, and the exit end of flow pump connects the microreactor entrance;

(2) open first organic phase flow pump, enter the microchannel of microreactor until organic phase after, pressing 0.65 times of the organic phase flow sets and open water phase flow rate pump again, pass through simultaneously the two-phase laminar flow phase interface of formation in the observation by light microscope microchannel, regulate during this time the flow of two-phase, make the two-phase split flow;

Begin to separate when (3) two phase flow is to the place, Y type fork of microchannel outlet, flow out microreactor from outlet separately, and two-phase is collected respectively, indium is extracted and enters organic phase, and iron and zinc are kept aqueous phase, has realized separating of indium and iron, zinc.

2. the microfluid extracting process of extracting and separating In according to claim 1 and Fe, Zn, it is characterized in that: the described sulfuric acid system solution that contains indium, iron, zinc is the leach liquor in the hydrometallurgy zinc process.

3. the microfluid extracting process of extracting and separating In according to claim 1 and Fe, Zn, it is characterized in that: described solvent oil is conventional solvent oil.

4. the microfluid extracting process of extracting and separating In according to claim 1 and Fe, Zn, it is characterized in that: the characteristic dimension of described microchannel is 160～800 μ m, and length is 80～480mm.

5. the microfluid extracting process of extracting and separating In according to claim 1 and Fe, Zn is characterized in that: the duration of contact of described two-phase in the microchannel is 0.01～10s.

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