JP2001192750A - Continuous distillation device for obtaining high-purity mercury - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous mercury distillation device which is capable of stably obtaining high-purity mercury containing the impurity metals included in the mercury at a lesser amount. SOLUTION: The continuous mercury distillation device is installed with a rectification column (4) in mid-way of a mercury distillation tank (3) and cooler (5), is contained with fillers (31) performing the purpose of fractionation in the rectification column (4) and is provided with a filter pass mechanism for vaporized mercury. A stainless steel filter (33) is mounted or suitably one or six sets of plural heat resistant filter sets (41) are diagonally and gastightly mounted in the form of shutting off the mercury vaporization passage as the filter mechanism. The heat resistant filter sets (41) are used by combining arbitrary one to three sheets selected from glass fiber filter paper (38) and filter paper (39) made of ethylene tetrafluoride resins, packings (40) maintaining gastightness and stainless steel wire nets (37) for mechanical reinforcement at need to constitute one set. The distillation is executed by adding a filter pass function for the vaporized mercury to the respective filter mechanisms by providing the same with pinholes for reflux of the vaporized mercury according to the respective filter mechanisms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous mercury distillation apparatus capable of stably obtaining high-purity mercury containing a small amount of impurity metals contained in mercury.

[0002]

2. Description of the Related Art At present, in Japan, mercury recovered from mercury-based waste is mainly recycled to the market, and crude mercury recovered from waste is different from conventional mercury obtained from ore. The quality and quantity of impurities are different, and the types of impurities are also diverse and complicated. In order to purify such crude mercury, it must be said that it is not sufficient to follow the conventional method.

FIG. 2 is a system diagram of a conventional mercury continuous distillation apparatus. The part of the device that comes into contact with mercury is mainly made of stainless steel and partly made of glass. The raw material mercury before purification in the mercury distillation tank (3) includes iron, zinc, lead,
Copper, nickel, cadmium, chromium, silver, calcium,
Contains impurity metals such as sodium. When the distillation starts, in the space of the mercury distillation tank (3), in addition to the impurities present as a gas together with the mercury vapor, some of them are suspended in fine solid particles. When mercury to which impurities are added is vacuum-distilled using an all-glass evaporator, the floating of powdery impurities in the space of the distillation flask can be clearly observed with the naked eye. Is considered to be universal, albeit to varying degrees. Further, some impurities present in the space of the mercury distillation tank (3) behave together with mercury with the progress of distillation, are cooled by the cooler (5) through piping, and are mixed with liquefied mercury. Therefore, there are impurities in the form of fine solid particles in addition to impurity metals which enter into the azeotropic phenomenon with mercury, and impurities contained in mercury in the purified mercury tank (7) obtained by distillation should be eliminated to a very small extent. Will be extremely difficult.

[0004]

If the mercury obtained by distillation is left undisturbed, impurities and metal oxides float on the surface of the mercury, or a dark black streak appears on the wall of the glass container. Thereafter, it is usual to remove the impurity particles by physical filtration. In other words, distillation and filtration are considered as a set in the final purification step. As an example of a specific filtration method, first, a relatively large impurity particle is removed by vacuum filtration using a glass filter, and then a pinhole is opened at a tip which becomes a bottom of the four-fold cellulose filter paper. To remove the suspended foreign substances on the mercury surface. However, although different depending on the type of filter medium, when a filter medium having a retained particle size of several μm to several tens of μm or less is used, mercury does not pass even by vacuum filtration, and a filtration method of opening a pinhole in the filter paper and passing mercury at the bottom is performed. Since the mixed microparticles cannot be completely removed and the impurity metals that make up mercury and amalgam cannot be excluded by filtration, impurities can be removed to a very small extent by the conventional purification operations by distillation and filtration of mercury. This was difficult and the purification effect was limited. SUMMARY OF THE INVENTION An object of the present invention is to provide a continuous distillation apparatus capable of stably obtaining purified mercury containing a smaller amount of impurity metals than conventional methods, and a method for implementing the same.

[0005]

According to the present invention, a mercury distillation tank 3 and a cooler 5 are provided to solve the above-mentioned problems and achieve the object.
The rectification tower 4 is installed in the middle of the process, the inside of the rectification tower 4 is filled with the fractionating filler 31, and a stainless steel cartridge filter 33 is attached. Alternatively, instead of providing a cartridge filter, a plurality of heat-resistant filter sets 41, one to six of which are suitable, are attached obliquely and airtightly in such a manner as to block the mercury vapor passage. The gist of the present invention is that, in order to add a function of passing all the mercury vaporized during distillation through a heat-resistant filter material, it is essential to install a heat-resistant filter set 41 using a stainless steel cartridge filter 33 or filter paper in the constituent elements. It is to be.

The stainless cartridge filter (33) installed inside the rectification column (4) has a nominal pore size of 3 to 40.
A 1 to 3 mm pinhole (3 mm) was used for a stainless steel tube (34), which was sealed at the lower end with a cartridge filter attached, for refluxing liquefied mercury.
5) is provided. In the case where a plurality of heat resistant filter sets (41) each having 1 to 6 sets are appropriately mounted, one filter set (41) has a retention particle diameter of 0.3 to 1.0 μm.
m glass fiber filter paper (38) and retention particle size 2-10
1 to 3 sheets selected from filter paper (39) made of polytetrafluoroethylene resin having a thickness of μm, and arbitrarily combined with each other. A pinhole of 1 to 3 mm is provided at the lowest position.

[0007] As the filler for fractionation 31, Rahis ring,
It is selected from McMahon Packing, Helipak, Dickson Packing, etc., and a ribbon heater and a heat insulating material are wound around the rectification column while heating and keeping the temperature.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a system diagram of a continuous mercury distillation apparatus according to the present invention. In the apparatus, a portion to which mercury touches is mainly made of stainless steel and a part is made of glass. A rectification column 4 is installed at a rising point of a pipe leading from the mercury distillation tank 1 to the cooler 5. As shown in FIG. 3, the inside of the rectification column is filled with a fractionating filler 31 and a stainless steel cartridge filter 33 is installed. The stainless steel cartridge filter 33 is made of all stainless steel having a nominal hole diameter of 3 to 40 μm from the viewpoint of heat resistance, and a cylindrical or pleated type media can be used. Further, a pinhole 35 of 1 to 3 mm is provided for mercury reflux in a stainless steel tube 34 that seals the lower end of the lower part of the cartridge filter.

Instead of providing the stainless steel cartridge filter 33, a plurality of heat-resistant filter sets 41, one to six sets of which are suitable, may be obliquely and airtightly mounted so as to block the mercury vapor passage. One set of heat-resistant filter sets 41 is composed of one to three sheets selected from glass fiber filter paper 38 having a retention particle diameter of 0.3 to 1.0 μm and filter paper 39 made of tetrafluoroethylene resin having a retention particle diameter of 2 to 10 μm. And any combination thereof. Glass fiber filter paper 38 is 0.2-0.8mm thick, heat resistant temperature 500 ℃
And the filter paper 39 made of tetrafluoroethylene resin has a thickness of 0.3.
Those having a temperature of up to 1.0 mm and a heat resistance temperature of 260 ° C. are used.
The total number of heat-resistant filter papers used in a plurality of heat-resistant filter sets 41, one to six of which is appropriate, is determined in accordance with the degree of distillation purification and the requirements of the distillation speed. However, when filter paper having a large retaining particle diameter is used, more than 16 sheets are possible, and the gist of the present invention is to specifically specify the number of sets of the heat resistant filter set 41 and the total number of filter papers to be used. It is not limited.

For example, four heat resistant filter sets 41
4 is installed obliquely and airtightly in a manner to shut off the mercury vapor passage when it is installed inside the rectification column 4.
(A), (b), and (c). However, any method is possible, and the present invention does not limit the method. Further, in the filter paper constituting each heat resistant filter set 41, mercury vapor is liquefied and accumulated at the lowest position on the surface through which vaporized mercury passes, so that the mercury is released to the mercury distillation tank 3. It is important to make pinholes of appropriate size.
In this case, an appropriate size pinhole is 1 to 3 m in diameter.
m, preferably 1.5 to 2.0 mm in diameter. The height at which liquid mercury accumulates at the bottom of the filter paper is determined by the pinhole diameter. With an optimum pinhole diameter, a suitable small amount of mercury will accumulate at the bottom of the filter paper, the holes will always be closed by liquid mercury, and more mercury will escape under the filter paper and reflux. However, if the pinhole is smaller than 1 mm, it becomes difficult for liquid mercury to pass through the pinhole and fall down, and a large amount of liquid mercury is accumulated on the filter paper. If a large amount of mercury accumulates, there is a disadvantage that the area of the filter paper through which the vaporized mercury passes decreases and the distillation rate is reduced, or that the filter paper cannot withstand the weight of the accumulated mercury and is damaged.

FIG. 5 shows the shapes of the glass fiber filter paper 38 and the filter paper 39 made of ethylene tetrafluoride resin, and the shapes of the stainless steel wire netting 37 and the packing 40, which are attachment aids. In each case, the outermost side has the same ellipse in order to be set obliquely in the cylindrical rectification column, and the major axis of the ellipse is determined based on the inclination gradient of the filter to be installed. The gradient of the filter is 5 ° to 30 ° with respect to the horizontal.
Is suitable.

FIG. 6 shows a state in which the glass fiber filter paper 38 and the filter paper 39 made of ethylene tetrafluoride resin are attached to the rectification column 4. The stainless steel round frame 36 is a cylinder which just fits inside the rectification column, and is cut obliquely to the horizontal according to the gradient of the filter to be installed. The figure shows a state in which a heat-resistant filter set 41 is placed on a stainless steel round frame 36 that is cut diagonally, and a stainless steel round frame 36 is placed over the stainless steel round frame 36 to set one set of filters. As a detailed configuration example of the heat resistant filter set 41, a packing 4
0, a filter paper 39 made of polytetrafluoroethylene resin, a glass fiber filter paper 38, a filter paper 39 made of polytetrafluoroethylene resin, and a stainless steel wire mesh 37 are laminated in order. It is integrated with the agent. One to three to three filter papers can be used, and if a large number of sets are used, an arbitrary plural number of filter papers can be set. Glass fiber filter paper 3
No. 8 is advantageous in that the retained particle size is small, but has a disadvantage in that it has low mechanical strength and sometimes cannot withstand the weight of mercury. Therefore, ethylene tetrafluoride having a large retained particle size but strong mechanical tension. It is good to use in combination with the resin filter paper 39. The stainless steel round wire mesh 37 is used for reinforcement of the uppermost and lowermost stages where pressure is particularly applied before and after use.

The bottom of the rectification column is filled with a packing material for fractionation 32, and a stainless steel cartridge filter 33 made of all stainless steel shown in FIG. 3 or a filter cartridge 1 shown in FIG.
A plurality of heat-resistant filter sets 41 each having a suitable number of sets are set. The filler 31 for fractionation is selected from Lahiscilling, McMahon packing, Helipak, Dickson packing and the like. If the inside of the rectification column 4 can be set, the mercury distillation tank 3 and the cooler 5
The main heater 14 is attached to the mercury distillation tank 3 and a heat insulating material is wound. The outside of the rectification column 4 is wound with a ribbon heater and a heat insulating material so that necessary heating and heat keeping can be performed.

In FIG. 1, switching cocks 13, 20,
When the vacuum pump 27 is operated after opening the valve 22 and turning on the solenoid valve 10, the pressure inside the apparatus is reduced, and the mercury in the mercury receiver 6 rises in the pipe leading to the cooler 5.
The mercury in the mercury supply tank 1 is supplied into the mercury distillation tank 3 via the mercury charging container 2. Main heater 14
When the ribbon heater wound around the rectification tower 4 is turned on, the mercury is heated and turned into steam. The vaporized mercury ascends to the rectification tower 4, passes between the fractionation packing materials 31, and passes through the gaps between the heat-resistant filter medium fibers. During this time, the fine particulate matter is removed from the impurities by the physical action that cannot pass through the filter medium and the fractionation effect, and the purified mercury vapor advances to the cooler 5 and is liquefied.

When the amount of mercury in the mercury distillation tank 3 is reduced by distillation, the amount of mercury in the mercury charging container 2 is increased and supplied because it is necessary to maintain a vacuum balance. The mercury charging container 2 is provided with a level sensor 11, and the solenoid valve 10 is operated as the mercury level decreases, so that mercury in the mercury supply tank 1 is supplied. On the other hand, the mercury cooled by the cooler 5 is temporarily stored in the mercury receiver 6 and then flows into the purified mercury tank 7. Thus, the mercury is continuously distilled, but the mercury in the mercury distillation tank 3 continues to be distilled, and the amount of impurities gradually increases. Therefore, the distillation is stopped when the impurity concentration becomes high. To remove mercury.

[0016]

EXAMPLE Mercury obtained by distilling raw material mercury having the same composition using the continuous mercury distillation apparatus of the present invention shown in FIG. 1 and mercury distilled using the conventional continuous mercury distillation apparatus shown in FIG. Analyzes were made with mercury that was filtered twice using a filter paper with a pinhole at the tip.

The conditions for continuous distillation of mercury are as follows: in the distillation using the continuous mercury distillation apparatus of the present invention shown in FIG.
146-149 ° C, the mercury distillation tank temperature was 195-198 ° C, the degree of vacuum was 3 mmHg, and the distillation rate was 1.4-1.6 kg-Hg / hour. In the rectification column, McMahon packing was used as a packing material for fractionation.
In the manner described above, a glass fiber filter paper having a retained particle diameter of 0.3 μm is sandwiched between two filter papers made of tetrafluoroethylene resin having a retained particle diameter of 10 μm in the uppermost and second stages. Is a filter made of tetrafluoroethylene resin having a retention particle diameter of 10 μm.
The stacked sheets were used. The distilled mercury was taken out of the purified mercury tank and filtered using a four-folded cellulose filter paper with a pinhole formed at the tip of a cone, and this filtration was repeated once more.

In the distillation using the conventional continuous mercury distillation apparatus shown in FIG. 2, the mercury distillation tank was continuously operated day and night at a temperature of 143 to 146 ° C., a degree of vacuum of 3 mmHg, and a distillation rate of 2.1 to 2.3 kg-Hg / hour. . The distilled mercury was filtered twice using a four-folded cellulose filter paper having a pinhole at the tip of the cone.

In the analysis method, 500 g of each filtered mercury is taken and shaken for 1 hour in a separating funnel with 100 ml of a 50-fold diluted nitric acid to obtain an aqueous layer. Mercury layer again 5
Shake with 100 ml of 0-fold diluted nitric acid for 1 hour to remove the aqueous layer. The mercury layer is finally washed twice with 100 ml of water, and the diluted dilute nitric acid extract and the two washings are combined and concentrated by heating. The concentrated solution is placed in a volumetric flask, and after quantification, the contained metal is measured by an atomic absorption method.

When the mercury distilled using the continuous mercury distillation apparatus of the present invention was filtered twice through a pinhole filter paper, the measured values of the impurity metals in the mercury were 0.02 ppm or less for Fe;
02 ppm, Pb: 0.02 ppm or less, Cu: 0.0
2 ppm or less, Ni: 0.02 ppm or less, Cd: 0,
02 ppm or less, Cr; 0.02 ppm or less, Ag;
0.02 ppm or less, Ca; 0.07 ppm, Na;
It was 0.05 ppm.

On the other hand, the measured values of impurity metals in mercury obtained by filtering mercury distilled by the conventional continuous mercury distillation apparatus shown in FIG. 2 twice through a pinhole filter paper are Fe: 0.56 ppm,
Zn; 0.36 ppm, Pb; 0.14 ppm, Cu;
0.05 ppm, Ni: 0.02 ppm, Cd: 0.0
2 ppm, Cr: 0.02 ppm or less, Ag: 0.03
ppm, Ca; 3.8 ppm, and Na; 1.7 ppm.

Further, 500 g of mercury distilled using the mercury continuous distillation apparatus of the present invention filtered twice with a pinhole filter paper is put into a glass bottle for mercury, and the contents of the bottle are allowed to stand at room temperature for one week. Did not change at all. In contrast,
When mercury distilled by a conventional continuous mercury distillation apparatus was filtered and allowed to stand by the same method, light gray streaks were adhered to the inside of the glass where the mercury surface was in contact with the container.

[0023]

According to the mercury distillation apparatus of the present invention provided with a rectification tower provided with a function of passing all vaporized mercury through a filter, the mixing of fine particle impurities is reduced,
As the fractionation effect increases, the ability to purify mercury increases. Also, the mercury supply section and the mercury distilling section of the distillation apparatus are sealed with mercury to shut off from the outside air.Mercury is supplied from the mercury supply tank to the mercury distillation tank as needed, so that the Distillation can be performed, and high-purity mercury containing few impurity metals can be stably obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of a continuous mercury distillation apparatus according to an embodiment of the present invention. The case where a stainless steel cartridge filter was attached inside the rectification column and the case where four sets of heat resistant filters were attached were shown.

FIG. 2 is a system diagram of a conventional mercury continuous distillation apparatus.

FIG. 3 is a view showing a situation in which a fractionating filler and a stainless steel cartridge filter are installed in a rectification column.

FIG. 4 is a diagram showing a third example of a method of attaching four heat-resistant filter sets to the rectification column.

FIG. 5 is a view exemplifying shapes of filter paper and attachment accessories constituting a heat resistant filter set.

FIG. 6 is a diagram exemplifying a configuration and a mounting state of a heat resistant filter set mounted inside a rectification tower.

[Explanation of symbols]

1 Mercury supply tank 2 Mercury charging container 3 Mercury distillation tank 4 Rectification tower 5 Cooler 6 Mercury receiver 7 ‥‥ Purified mercury tank 8 ‥‥‥‥ Mercury 9 ‥‥‥‥ Cooling water 10 ‥‥‥‥ Solenoid valve 11 ‥‥‥‥ Level sensor 12 ‥‥‥‥ Glass tube 13 ‥‥‥‥ Switching cock 14 ‥‥‥ ‥ Main heater 15 ‥‥‥‥ Temperature sensor 16 ‥‥‥‥ Flange 17 ‥‥‥‥ Flange 18 ‥‥‥‥ Temperature sensor 19 ‥‥‥‥ Flange 20 ‥‥‥‥ Switching cock 21 ‥‥‥‥ Glass tube 22コ ッ ク Switching cock 23 ‥‥‥‥ Thick rubber tube 24 ‥‥‥‥ Vacuum bottle 25 ‥‥‥‥ Silicon rubber stopper 26 ‥‥‥‥ Water absorbent cotton 27 ‥‥‥‥ Vacuum pump 28 ‥‥‥‥ Switching cock 29 ‥‥‥‥ Packing 30 ‥‥‥‥ Vol Nut 31 ‥‥‥‥ Filler for fractionation 32 ‥‥‥‥ Wire mesh (stainless steel) 33 ‥‥‥‥ Stainless steel cartridge filter 34 ‥‥‥‥ Stainless steel tube 35 ‥‥‥‥ Pin hole position 36 製 Stainless steel Round frame 37 ‥‥‥‥ Stainless steel wire gauze 38 ‥‥‥‥ Glass fiber filter paper (oval) 39 濾 Ethylene tetrafluoride resin filter paper (oval) 40 ‥‥‥‥ Packing (oval) 41 ‥‥‥‥ Heat resistant filter set (37, 38, 39
And 40 are combined and integrated as required)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D076 AA05 AA16 AA22 BB04 BC03 CA19 CD22 DA22 EA03X EA12X EA14X FA03 FA18 FA33 FA37 HA03 JA03 4K001 AA14 BA23 EA01 EA06 GA15

Claims (3)

[Claims] In a continuous mercury distillation apparatus, a rectification tower (4) is installed at a rising point of a pipe leading from a mercury distillation tank (3) to a cooler (5), and a rectification tower is provided inside the rectification tower (4). A function to fill the filler material (31) and attach a stainless steel cartridge filter (33) or a plurality of heat-resistant filter sets (41), one to six of which are appropriate, so that all vaporized mercury passes through the filter. A continuous distillation apparatus for mercury, wherein distillation is performed with addition of water. 2. A fractionating filler (3) is provided inside the rectification column (4).
1) and an all-stainless stainless steel cartridge filter (3
3) Install a stainless steel tube (34) that seals the lower end of the lower part of the cartridge filter for reflux of liquefied mercury.
The apparatus for continuously distilling mercury according to claim 1, characterized in that the apparatus is provided with a pinhole (35) of 1 to 3 mm. 3. A fractionating filler (3) is provided inside the rectification column (4).
A plurality of heat-resistant filter sets (41) each of which is filled with 1) and one to six sets are installed diagonally and airtightly so as to block the mercury vapor passage. One filter set (41) was selected from glass fiber filter paper (38) having a retention particle diameter of 0.3 to 1.0 μm and filter paper (39) made of tetrafluoroethylene resin having a retention particle diameter of 2 to 10 μm. Claims 1 to 3 are characterized in that a combination of 3 to 3 sheets is provided, and a pinhole of 1 to 3 mm is provided at the lowest point on the surface of each filter paper through which vaporized mercury passes for reflux of liquefied mercury. Item 2. A continuous distillation apparatus for mercury according to Item 1.