JP2006232662A - Transportation method and transportation container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inexpensively, stably and safely transporting a solution containing an iodine component and to provide a container to be used in the method for efficiently recovering the iodine component as a precious resource. <P>SOLUTION: The transportation method includes steps of: adding an alkali compound to a liquid having less than 10 mass% concentration of at least one kind selected from a group consisting of simple iodine, compounds containing iodine, iodine ion and ions containing an iodine element, so as to control the pH; concentrating the liquid obtained by the above step of controlling the pH so as to obtain a concentrated liquid having 10 to 40 mass% of at least one kind selected from a group consisting of simple iodine, compounds containing iodine, iodine ion and ions containing an iodine element; and transporting the concentrated liquid. The transportation container is used in the above method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transport method and a transport container, and in particular, a stable and safe liquid containing at least one selected from the group consisting of simple iodine, a compound containing iodine element, iodine ion, and an ion containing iodine element. The present invention relates to a method for transporting to a container and a transport container used therefor.

  Iodine, which is a halogen element, often exists in the form of a compound with other elements in nature, and is a resource that is rarely contained in the crust, seawater, and the like. Examples of use for humans include use as essential minerals that support biological reactions, and examples of use as industrial resources include pharmaceutical, industrial, and agricultural uses of the antibacterial, oxidizing, and reactive properties of iodine. There are uses as raw materials and intermediates for various products such as for use. The usage scene and usage amount tend to increase. With regard to the supply of iodine that is useful and has many needs, iodine is often present as a water-soluble salt in nature, and its distribution is sparse, so mining requires large-scale facilities, This can lead to high costs. Therefore, iodine is positioned as a rare resource with limited output.

  Thus, the reuse of iodine, which is a valuable resource, has become an important issue in terms of meeting increasing demand and further reducing the environmental burden by preventing discharge at high concentrations.

  Iodine is a substance that cannot be easily used because it is expensive and highly reactive. Therefore, when using iodine, the amount of iodine used at a time is small. Furthermore, since the public's awareness of reducing the environmental burden was not necessarily high, except for rare cases, the iodine component after use was either drained as it was or treated as industrial waste. The iodine component recovery technology known so far is burning the liquid containing the iodine component and purifying the resulting incinerated ash, etc. Regarding the liquid containing iodide that should be a useful resource, However, there was only a specification for sending it to a treatment facility as wastewater generated (see Patent Documents 1 and 2).

Regarding the handling of liquids containing iodine components on the premise of resource recovery, it must be kept in mind that iodine is a deleterious substance having the property of easily sublimating and corrosive. For solutions containing iodine components, consideration must be given to the stability and safety during storage and transportation in consideration of the impact on living organisms and the environment, but there must be a means for stable and safe storage and transportation. For example, there is a method of preparing a container with high hermeticity so that iodine is not generated by air oxidation, and filling the container with nitrogen. Ensuring the sealing of the container is not only disadvantageous for the sustainability of the collection business itself, but also increases the cost, and also changes in pressure in the container due to temperature differences. There are many disadvantages in handling because it is limited to certain things and becomes heavy (see Patent Document 3). Furthermore, if the waste liquid is acidic, the material of the container is not limited to simply using a metal, but processing such as a special alloy such as Hastelloy or Teflon (registered trademark) coating is complicated and expensive.
Japanese Patent Laid-Open No. 51-34896 JP 2004-35302 A JP 2004-331155 A

  Accordingly, an object of the present invention is to provide a method for transporting a solution containing an iodine component in an inexpensive, stable and safe manner, and a container used therefor, in order to efficiently recover a iodine component, which is a valuable resource. It is to provide.

  Said subject is solved by following (1)-(7).

(1) An alkaline compound is added to a solution having a concentration of at least one selected from the group consisting of simple iodine, a compound containing iodine element, iodine ion, and an ion containing iodine element of less than 10% by mass, and pH Adjusting the process,
In order to obtain a concentrated solution having a concentration of 10 to 40% by mass selected from the group consisting of simple iodine, a compound containing iodine element, iodine ion, and ion containing iodine element, the pH is adjusted. A step of concentrating the liquid obtained in the step;
Carrying the concentrated liquid;
A method for transporting a liquid, comprising:

  (2) The method according to (1) above, wherein the pH of the liquid obtained in the step of adjusting the pH is 7 to 13.

  (3) In the step of adjusting the pH, the solution before the alkali compound is added is composed of simple iodine, a compound containing an alkali metal and an iodine element, a compound containing an alkaline earth metal and an iodine element, and ammonium iodide. The method according to (1) or (2) above, comprising at least one substance selected from the group consisting of:

  (4) The method according to any one of (1) to (3), wherein the alkali compound is an alkali hydroxide.

  (5) A container for storing and transporting the concentrated liquid obtained in the process of concentrating liquid, which is included in the method according to any one of (1) to (4).

  (6) The container according to (5), wherein the container includes a pressure adjustment hole.

  (7) The container according to (5) or (6) above, wherein the container is in the form of a drum, a tank, or a container.

  According to the present invention, a liquid containing an iodine component to be recovered can be transported inexpensively, stably and safely.

  FIG. 1 is a flow sheet showing processing steps for stably storing a liquid containing an iodine component to be recovered (hereinafter referred to as a recovered liquid) and transporting it safely. The recovered liquid contains at least one selected from the group consisting of simple iodine, a compound containing iodine element, iodine ion, and ion containing iodine element (hereinafter referred to as iodine content). Specifically, the iodine content includes simple iodine, sodium iodide, potassium iodide, lithium iodide, sodium iodate, potassium iodate and other compounds containing an alkali metal and iodine element, calcium iodide, magnesium iodide, Compounds containing alkaline earth metals and elemental iodine such as barium iodide, calcium iodate, magnesium iodate, ammonium iodide, europium iodide, copper iodide, zinc iodide, barium iodate, or hydrates thereof Inorganic compounds containing iodine element such as iodine, organic compounds containing iodine element such as methyl iodide, ethyl iodide, etc. are preferable, simple iodine, compounds containing alkali metal and iodine element, compounds containing alkaline earth metal and iodine element And ammonium iodide is more preferred. The concentration of iodine in the recovered liquid is less than 10% by mass, preferably 2-8% by mass.

  In the pH adjusting step 2, a pH adjusting agent 3 which is an alkali compound, preferably an alkali hydroxide such as potassium hydroxide or sodium hydroxide is added to the recovered liquid to adjust the pH to 7 or more. While the recovered liquid is concentrated in the next step or due to a rise in liquid temperature or a change in liquid properties during storage and transportation of the recovered liquid, sublimable iodine is generated and scattered, reducing the amount of iodine to be recovered In order to prevent toxicity to humans and deterioration of the materials of the device and container, the pH of the liquid containing iodine can be changed from acidic conditions where sublimable iodine is easily generated to alkaline conditions. Necessary. The pH of the liquid after adding the alkali compound is preferably 7 to 13, more preferably 7.5 to 13, and still more preferably 8 to 12. Excessive alkalization is undesirable because it consumes alkali unnecessarily. It is known that ammonium iodide is easily decomposed by a change in liquid temperature or a change in physical properties of the liquid. If a strong base is allowed to act on a solution containing ammonium iodide in advance, not only the effect of the present invention but also ammonia is expelled from ammonium iodide as a gas prior to storage and transportation. It can be removed safely, and can prevent unexpected gas generation during storage and transportation. At this time, the concentration of iodine in the recovered liquid is, for example, 10% by mass or more, and when the concentration does not need to be performed, it can be handled as the concentrated recovered liquid 6 as it is.

  In the concentration step 4, the recovered liquid having a relatively low iodine content is concentrated to improve the convenience of storage and transportation. The concentration method may be a conventional method for concentrating liquids, but in order to prevent generation of sublimable iodine alone, the method of the present invention includes a step of adding an alkali compound before concentration. Including. In the method of the present invention, an evaporation concentration method under normal pressure or reduced pressure is preferable. By adding an alkali compound, the corrosiveness to the material of the apparatus and the container, particularly the metal is reduced, and there is an advantage that a metal material having excellent thermal conductivity can be used for the apparatus. Further, the condensed water 5 by-produced during the concentration has an advantage that it can be reused immediately as distilled water. The degree of concentration of the collected liquid is 10 to 40% by mass as the iodine content. Excessive concentration is likely to cause disadvantages in handling due to an increase in the viscosity and specific gravity of the concentrate, and bumping of the concentrate due to precipitation of crystal components, so the concentration of iodine in the concentrated liquid is preferably 20 to 30% by mass. If the recovered liquid contains an organic solvent, it can be removed in the concentration step. If it does not contain the organic solvent, the condensed water 5 obtained in the concentration step can be reused as high-quality industrial water. is there. The concentrated recovery liquid 6 is managed so as to be used for storage 7 or transportation 8 as a subsequent process.

FIG. 2 shows a container for safely storing and transporting the concentrated and recovered liquid 6 obtained as described above. What is shown in the figure is a container 10 having a capacity of about 1 m ³ . From the upper lid 11 adjusted to the same height as the main body, the concentrated recovery liquid 6 is pumped or the like (not shown) so that the liquid level does not exceed the pressure adjustment hole 12 provided in the upper side of the container 10. Fill. An upper lid 11, a pressure adjusting hole 12, and a lower valve 13 having a structure in which protrusions are reduced as much as possible so that the containers 10 can be loaded or arranged without gaps when being stored and transported are provided on the container body. On the other hand, it is provided in a recessed position. Thereafter, when the liquid recovery process is performed, the liquid is sent to the recovery processing apparatus via the upper lid 11 or the lower valve 13. FIG. 3 is a schematic diagram of the in-vehicle tank 20. The concentrated recovery liquid 6 is filled into the in-vehicle tank 20 with a pump or the like (not shown) from the manhole 21 or the liquid inlet valve 22. The pressure adjustment hole 24 is provided in the upper portion of the tank so that the nozzle faces downward so that rainwater or the like does not enter directly. In performing the liquid recovery process after storage and transportation, the liquid is sent via the manhole 21 or the liquid outlet valve 23. As a material of the container, a metal such as stainless steel, a resin such as polyethylene can be used, but there is no particular limitation. When a resin such as polyethylene is used as the material of the container, it is preferable to cover the outer periphery with a metal frame or the like in order to maintain strength.

  FIG. 4 is a schematic view showing an example of a usage pattern of the container described in FIG. What is shown in the figure is the arrangement of the container 30 having the same structure as the container 10 shown in FIG. The concentrated recovery liquid 6 is sent to a container 30 installed indoors or outdoors via a pipe 31 with a pump or the like (not shown). FIG. 5 shows an embodiment of transporting the concentrated recovery liquid by the container 40 having the same structure as that described with reference to FIG. FIG. 6 is an embodiment showing the transport of the concentrated recovery liquid in the tank lorry shown in FIG. 3, and the concentrated recovery liquid is sent to the in-vehicle tank 50 via the pipe 51.

  The concentrated recovery solution thus obtained is transferred to an iodine recovery step as necessary. For example, chlorine gas is blown into the concentrated recovery liquid, and simple iodine can be precipitated by its oxidizing action, and can be recovered by a conventional method.

  Next, the present invention will be described in more detail with reference to examples. The measurement of iodine ion concentration is based on the measurement method described in “6. Test method (1) Purity (after drying)” in JIS standard K8913 “Potassium iodide (reagent)”. It measured by the acid potassium titration method.

Example 1
Sodium hydroxide was added to an aqueous sodium iodide solution having an iodine ion concentration of 8% by mass to adjust the pH to 9. Next, the obtained liquid was concentrated using an evaporator to obtain a concentrated liquid having an iodine ion concentration of 24% by mass. The concentrated solution thus obtained was transported to an iodine recovery device by a tank lorry similar to that shown in FIG.

  This concentrated liquid was transferred into an iodine recovery apparatus, and chlorine gas was supplied at a rate of 70 g with respect to 1 kg of the concentrated liquid. Thereafter, the generated precipitate was transferred to a melter kettle, and iodine was collected from the lower part of the melter kettle. The iodine recovery rate was 95% with respect to iodine ions contained in the sodium iodide aqueous solution before being evaporated and concentrated.

(Example 2)
After preparing 100 g of a potassium iodide solution having an iodine ion concentration of about 2% by mass, a 5% by mass aqueous potassium hydroxide solution was added to adjust the pH of the potassium iodide solution to about 12. Thereafter, the potassium iodide solution was evaporated and concentrated in the same manner as in Example 1, and the iodine ion concentration of the potassium iodide solution was measured. The results are shown in Table 1 below.

(Comparative example)
After preparing 100 g of a potassium iodide solution having an iodine ion concentration of about 2% by mass, a 5% by mass sulfuric acid aqueous solution was added to adjust the pH of the potassium iodide solution to about 2. Thereafter, the potassium iodide solution was evaporated and concentrated in the same manner as in Example 1, and the iodine ion concentration of the potassium iodide solution was measured. The results are shown in Table 1 below.

  As can be seen from Table 1, when the potassium iodide solution was acidified, the liquid was colored by free iodine from the time of pH adjustment. The theoretical value of the potassium iodide solution after evaporation and concentration is 20.12% by mass. Compared to this, the comparative example has a low iodine ion concentration, so that iodine was released into the air during evaporation and concentration. it is conceivable that.

  On the other hand, in Example 2 in which the potassium iodide solution was made alkaline, there is no change in the color of the solution during pH adjustment, so it is considered that iodine is not liberated. Further, since the concentration value of the potassium iodide solution after evaporation and concentration is almost the same as the theoretical value, it is considered that there is almost no release of iodine into the air during evaporation and concentration.

  The present invention can be suitably used in the field related to a technique for recovering iodine after using iodine.

It is a flow sheet which shows one embodiment of the transportation method of the present invention. It is the schematic which shows one Embodiment of the conveyance container of this invention. It is the schematic which shows other embodiment of the conveyance container of this invention. It is the schematic which shows one Embodiment of arrangement | positioning of the conveyance container of this invention shown in FIG. It is the schematic which shows other embodiment of the conveyance container of this invention. It is the schematic which shows other embodiment of the conveyance container of this invention.

Explanation of symbols

1 ... recovered liquid,
2 ... pH adjustment step,
3 ... pH adjuster,
4 ... Concentration process,
5 ... condensed water,
6 ... concentrated recovery liquid,
7 ... Storage,
8 ... transport,
10, 40 ... container,
20, 50 ... Car tank,
30 ... container,
11 ... Upper lid,
12, 24 ... Pressure adjusting hole,
13 ... Lower valve,
21 ... Manhole,
22 ... Liquid inlet valve,
23 ... Liquid outlet valve,
31, 51 ... piping,
42 ... Track.

Claims (7)

The pH is adjusted by adding an alkali compound to a liquid having a concentration of at least one selected from the group consisting of simple iodine, a compound containing iodine element, iodine ions, and ions containing iodine element being less than 10% by mass. Process,
In order to obtain a concentrated solution having a concentration of 10 to 40% by mass selected from the group consisting of simple iodine, a compound containing iodine element, iodine ion, and ion containing iodine element, the pH is adjusted. A step of concentrating the liquid obtained in the step;
Carrying the concentrated liquid;
A method for transporting a liquid, comprising:   The method according to claim 1, wherein the pH of the liquid obtained in the step of adjusting the pH is 7 to 13.   In the step of adjusting the pH, the liquid before the alkali compound is added is selected from the group consisting of simple iodine, a compound containing an alkali metal and an iodine element, a compound containing an alkaline earth metal and an iodine element, and ammonium iodide. 3. The method according to claim 1 or 2, characterized in that it comprises at least one selected material.   The method according to claim 1, wherein the alkali compound is an alkali hydroxide.   A container for storing, transporting, and storing the concentrated liquid obtained in the process of concentrating the liquid, which is included in the method according to claim 1.   The container according to claim 5, wherein the container includes a pressure adjusting hole.   The container according to claim 5 or 6, wherein the container is in the form of a drum, a tank, or a container.

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