JP2015000376A - Requirement determination apparatus for heavy-metal processing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a requirement of a heavy-metal processing agent simply, rapidly, inexpensively, and accurately when a heavy metal in a heavy-metal containing material such as fly ash is to be insolubilized.SOLUTION: For a requirement determination apparatus for a heavy-metal processing agent having a detector that can detect a turbidity change of a solution where heavy metals have been eluted out of a heavy-metal containing material and the function of calculating a requirement of the heavy-metal containing material from an addition amount of the heavy-metal processing agent at an end point where the turbidity change turns constant or at an inflection point of the turbidity change, an apparatus is used which has a transparence measurement container for supplying a heavy-metal solution, a mixer having the function of mixing the heavy-metal solution, a chemical agent injection part for supplying a heavy-metal processing agent for turbidity measurement from above the mixer, and a laser light source and light receiving part on a lateral part of the transparence measurement container.

Description

  The present invention relates to an apparatus used for determining a necessary amount of a heavy metal treatment agent when a heavy metal treatment agent is added to a heavy metal-containing substance to insolubilize the heavy metal.

  Fly ash discharged from municipal waste incineration plants and the like has a high heavy metal content and needs to be treated to suppress elution of heavy metals. As one of such treatment methods, there is a drug treatment method, and a method of insolubilizing heavy metals by adding a heavy metal treatment agent such as a chelate-based drug is used. In such a chemical treatment method, it is important to grasp the necessary amount of the heavy metal treatment agent in order to reliably perform the insolubilization treatment of the heavy metal.

  Until now, as a method of determining the required amount of heavy metal treatment agent, a heavy metal treatment agent is added to fly ash in a desktop test, pretreatment such as addition of humidified water and kneading is performed, and February 17, 1973 A method has been used in which a heavy metal elution test is performed by the method stipulated by the Environmental Agency Notification No. 13 and the concentration of heavy metal in the eluate is measured. However, the method of determining the required amount of heavy metal treatment agent by the Environmental Agency Notification No. 13 (hereinafter referred to as “No. 13 Test”) takes time and responds quickly to the changing fly ash. Was difficult.

  Under such circumstances, a method has been proposed in which the heavy metal concentration in heavy metal fly ash is measured by ICP, atomic absorption, fluorescent X-ray, etc., and the necessary amount of heavy metal treating agent is determined (see, for example, Patent Document 1). . However, in these methods, since the apparatus for measuring the heavy metal concentration is large and expensive, it is difficult to measure on-site at a low cost.

  In addition, a method for measuring the absorbance at a specific absorption wavelength of the chelating agent used has been proposed (see, for example, Patent Document 2). However, in order to measure the absorption wavelength peculiar to the chelating agent, an optical device that can be controlled to a peculiar and specific absorption wavelength that the chelating agent has is necessary, so that the apparatus becomes expensive. In addition, these methods are methods for measuring a released chelating agent, and are not methods for directly detecting the amount of heavy metals, and thus are not necessarily sufficient methods.

  Further, a method of measuring a redox potential (ORP) by adding a heavy metal treatment agent to a slurry of fly ash and water (for example, see Patent Document 3) or a method of measuring by a metal ion electrode that detects a potential different from the ORP (See, for example, Patent Document 4). However, these potential measurements are strongly influenced by interfering ions, and are not necessarily sufficient methods.

  For these problems, a method of measuring turbidity (for example, see Patent Document 5) has been proposed. However, the conventional method for measuring turbidity is not always sufficient when the heavy metal concentration is low.

Japanese Patent Application Laid-Open No. 11-70374 JP-A-10-337550 JP-A-8-309912 JP 2003-334513 A Japanese Patent No. 4599913

  The present invention provides an apparatus for simply, quickly, inexpensively and accurately determining the required amount of a heavy metal treating agent when insolubilizing heavy metals in a heavy metal-containing substance such as fly ash.

As a result of intensive studies on a method for determining the amount of heavy metal treatment agent necessary for insolubilizing heavy metals in heavy metal-containing materials such as fly ash,
(1) Detector capable of detecting turbidity change of a solution eluting heavy metal from a heavy metal-containing substance (hereinafter referred to as “heavy metal solution”) and end point at which the turbidity change becomes constant or inflection point of turbidity change In a heavy metal treatment agent necessary amount determination device having a function of calculating a required amount of a heavy metal treatment agent from the amount of addition of the heavy metal treatment agent, a transparent measuring container for supplying a heavy metal solution, a stirrer having a function of mixing the heavy metal solution, An apparatus for determining a necessary amount of a heavy metal treatment agent, comprising: a drug injection part for supplying a heavy metal treatment agent solution for turbidity measurement from above; and a laser light source part and a light receiving part at a side part of the transparent measurement container.

  (2) The required amount determination device for a heavy metal treatment agent as described in (1) above, wherein the injection port of the drug injection part is above the liquid surface of the heavy metal solution.

  (3) The required amount determination device for heavy metal treatment agent according to (1) or (2) above, wherein the upper part of the transparent measurement container is sealed or semi-sealed.

(4) Using the apparatus described in (1) to (3) above, stir the heavy metal solution in the transparent measurement container and supply the heavy metal treating agent solution continuously or intermittently to the transparent measurement container side. A method of measuring the transmitted light intensity by irradiating laser light from the side, and determining the necessary amount of the heavy metal treating agent from the degree of decrease in light transmittance (increase in turbidity).
As a result, it was found that the required amount of the heavy metal treating agent can be determined on-site in a short time and simply, and even when the heavy metal content is low, and the present invention has been completed. .

  Hereinafter, the apparatus of the present invention will be described in detail.

  The present invention calculates a necessary amount of a heavy metal treatment agent from a detector capable of detecting a turbidity change of a heavy metal solution and an addition amount of the heavy metal treatment agent at an end point at which the turbidity change is constant or an inflection point of the turbidity change. In the apparatus for determining the necessary amount of heavy metal treatment agent having a function, a transparent measurement container for supplying a heavy metal solution, a stirrer having a function of mixing the heavy metal solution, a drug injection unit for supplying a heavy metal treatment agent solution for turbidity measurement from the top thereof, Further, the present invention relates to an apparatus for determining the necessary amount of heavy metal processing agent having a laser light source part and a light receiving part at the side part of the transparent measuring container.

  In the present invention, an infrared laser or a visible laser is used as a detector capable of detecting a change in turbidity. In particular, by using a visible light laser, it is possible to detect turbidity caused by the reaction of a heavy metal eluted from a heavy metal-containing substance and a heavy metal treatment agent with high sensitivity, and it is possible to detect a lower concentration of heavy metal. Therefore, it is possible to determine the required amount of the heavy metal treating agent on-site in a short time, easily and with high accuracy even for a heavy metal-containing substance having a low concentration of heavy metal, which has been difficult in the past. .

  The wavelength of light used in the present invention is not particularly limited as long as a change in turbidity can be detected, but is preferably in the range of 600 to 760 nm. When a wavelength of less than 600 nm is used, the transmittance may be affected depending on the heavy metal treatment agent to be added.

  Further, in the present invention, having the laser light source part and the light receiving part at the side part of the transparent measuring container means that the light source part (irradiating part) and the light receiving part of the laser light are located beside the transparent measuring container. The laser light is emitted from the light source part, passes through the transparent measurement container, passes through the measurement medium (heavy metal solution), and passes through the opposite transparent measurement container to reach the light receiving part.

  In the present invention, a heavy metal treating agent is added to the heavy metal solution, and the turbidity of the solution is measured to determine the necessary amount of the heavy metal treating agent necessary for insolubilizing the heavy metal-containing substance.

  The turbidity in the present invention is a general index representing the amount of suspension present in a solution per unit volume or unit weight of the solution.

  The turbidity is measured by adding a heavy metal treating agent to a solution from which heavy metals are eluted, but the addition may be continuous or intermittent. In particular, it is preferable to measure in a stepwise manner after the suspension is stabilized by the added heavy metal treatment agent. The addition time interval is preferably several minutes, particularly 1 to 10 minutes, and the mixture is stirred.

  In the method of the present invention, it is not always necessary to measure the absolute value of turbidity, as long as the change in turbidity in a solution can be measured.

  The transparent measuring container used in the present invention is not particularly limited as long as it is a transparent container that can stir the content heavy metal solution, but examples of the stirring means include an electromagnetic stirrer, a mechanical stirring blade, and the like. Examples of the transparent container include a transparent glass container and a transparent plastic container. A transparent plastic container is preferred because it is less likely to break. Furthermore, it is preferable that the upper part of the transparent measurement container is sealed or semi-sealed for the purpose of preventing evaporation or scattering of the heavy metal solution. Here, semi-sealed means that a part of the upper open part of the transparent measuring container is covered with a lid or the like.

  In the present invention, the drug injection part for supplying the heavy metal treatment agent solution is installed at the upper part of the transparent measurement container, and the heavy metal treatment agent is supplied from the drug tank via a tube or the like by injection means such as a pump. And it is preferable that the injection port of a chemical | medical agent injection | pouring part exists above the liquid level of a heavy metal solution. The method for adding the heavy metal treating agent is preferably the automatic dropping method in terms of improving accuracy. In the case of automatic dripping, a syringe pump, a bellows pump, a piston pump, a gear pump, a hydraulic pump, and the like can be exemplified as a pump for injecting the heavy metal treatment agent. In particular, a pump that can adjust and add a single dose in the range of 0.005 to 0.200 mg and has a high standard accuracy with a standard deviation of 0.001 g or less is preferable. For example, a feed screw drive type syringe pump using a pulse motor is exemplified. can do.

  According to the apparatus of the present invention, a heavy metal treatment agent is added stepwise to a heavy metal solution, a heavy metal suspension is gradually formed, and the transmitted light intensity is measured with a laser beam. The required amount can be determined from the added amount of the heavy metal treating agent at the time when the amount of turbidity does not increase, that is, when the decrease in light transmittance (the increase in turbidity) disappears. That is, the addition amount of the heavy metal treatment agent at the end point at which the turbidity change becomes constant or at the inflection point of the turbidity change can be made the required amount as it is.

  In the present invention, the solution for eluting heavy metals from the heavy metal-containing substance is not particularly limited. For example, a mineral acid aqueous solution such as nitric acid and hydrochloric acid, an organic acid aqueous solution such as malic acid and phthalic acid, or a base such as ammonia and caustic is used. It can be illustrated. In order to elute the heavy metal present in the heavy metal-containing substance, it is preferable to use a carboxylic acid and / or hydroxycarboxylic acid having one or more carboxyl groups and having an asymmetric structure. The carboxylic acid and / or hydroxycarboxylic acid having at least one carboxyl group and having an asymmetric structure includes at least one carboxyl group dissolved in water and having an asymmetric structure and / or hydroxycarboxylic acid. There is no particular limitation as long as it is formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, oxaloacetic acid, pyruvic acid, benzoic acid, etc. anhydride, hydrate, aqueous solution; glycolic acid, Examples include anhydrides, hydrates, and aqueous solutions of hydroxycarboxylic acids such as lactic acid, glyceric acid, hydroxybutyric acid, malic acid, gluconic acid, and mandelic acid. Hydroxycarboxylic acids are preferred in terms of handling, and particularly in solid form. Certain glycolic acids, glyceric acid, hydroxybutyric acid, malic acid, gluconic acid, and mandelic acid are preferred.

  The pH of the elution solution of heavy metal is not particularly limited, but it is preferable to make the pH as easy to elute as much as possible in determining the necessary amount of the heavy metal treating agent necessary for treating the heavy metal eluted from the heavy metal-containing substance. . Moreover, after making the said solution into pH7 or more, a heavy metal processing agent is added and turbidity is measured. The pH of the solution for measuring turbidity is preferably 7 or more, particularly preferably 8 or more, and more preferably 10 or more, while it is preferable not to exceed pH14. Before adding a heavy metal treating agent and measuring turbidity, it is preferable to filter the solution once to eliminate turbidity. The alkali used for adjusting the pH to 7 or higher is not particularly limited as long as it is soluble in water. Anhydrides and hydrates of metal hydroxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide And aqueous solutions.

  Although the heavy metal processing agent in this invention is not specifically limited, The chemical | medical agent in general which has the effect made to react and insolubilize with a heavy metal can be used. Examples include chelating agents (amine carbodithioates and acetates), inorganic sulfides (sodium sulfide, iron sulfide, etc.), and piperazine carbodithioates (mono, It is preferable to use a bis body or a mixture thereof.

  Although the heavy metal containing material processed by this invention is not specifically limited, Fly ash, soil, other wastes, etc. can be illustrated.

  The type of heavy metal to be treated in the present invention is not particularly limited. For example, in addition to lead, copper, cadmium, zinc, nickel, mercury, chromium, and arsenic, metal components whose elution is regulated for environmental conservation may be exemplified. it can.

  By using the apparatus of the present invention, by adding a heavy metal treating agent to a heavy metal solution and measuring the turbidity of the solution, the heavy metal necessary for the insolubilization treatment of heavy metal-containing substances in a short time, simply and with high accuracy. The amount of treatment agent added can be determined.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Reference example 1
0.2 g of fly ash A (including Pb = 6400 ppm, Cu = 2200 ppm) and 3.5 g of DL-malic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added to 200 g of pure water and stirred for 1 minute. The heavy metal inside was eluted. The slurry was filtered through a membrane filter (manufactured by ADVANTEC: membrane filter pore size 0.45 μm), and then 20% sodium hydroxide solution was added to adjust the pH to 12. Next, 0.58 g of a 25-fold diluted solution of heavy metal treatment agent TS-275 (manufactured by Tosoh Corporation) is added to the eluate with a feed screw drive type syringe pump using a pulse motor, and the mixture is stirred for 30 minutes and suspended. Product was produced. As a result of copying 3 g of the suspension-containing liquid onto a quartz cell (1 mm × 1 mm × 45 mm) and measuring the transmittance at 650 nm which is a visible light wavelength with UV-3100 (manufactured by Shimadzu Corporation), 70% Met.

Reference example 2
The same operation as in Reference Example 1 was performed except that the measurement wavelength was 780 nm (infrared region). As a result, the transmittance was 79%. Despite containing a suspension with the same concentration, the transmittance was 9% higher than that of visible light at 650 nm, and the turbidity was detected as low.

Example 1
0.2 g of fly ash B (unknown sample) and 3.5 g of DL-malic acid (manufactured by Wako Pure Chemical Industries, Ltd.) are added to 200 g of pure water and stirred for 1 minute to elute heavy metals in the fly ash. It was. The slurry was filtered through a membrane filter (manufactured by ADVANTEC: membrane filter pore size 0.45 μm), and then the eluate was placed in a 200 mL glass beaker, and 20% sodium hydroxide solution was added to adjust the pH to 12. Next, the glass beaker was placed in a stirrer equipped with a visible light laser sensor composed of a projector and a light receiver as shown in FIG. The laser sensor is IB-10 (manufactured by Keyence) as a sensor head, IB-1000 (manufactured by Keyence) as an amplifier unit, HS-30D (manufactured by ASONE) as a stirrer, total length 25 mm, diameter 8 mm (manufactured by ASONE) )It was used. While stirring the solution, 0.038 g of a 25-fold diluted solution of the heavy metal treatment agent TS-275 (manufactured by Tosoh Corporation) from above the liquid surface with a pulse screw-driven syringe pump at a 3-minute interval. It was dripped 10 times at a time, and the change in the amount of suspension was detected from the amount of light received by the sensor unit. The results are shown in Table 1 and FIG. A clear inflection point was observed at the point of dropping three times. The total amount of dripping at the inflection point is 0.038 g × 3 = 0.114, and the heavy metal treatment agent TS-275 needs 0.114 g / 25 = 4.56 mg with respect to 0.2 g of fly ash. It was 2.28 wt% (4.56mg / 0.2gx100) with respect to ash.

  As a result of adding the required amount of heavy metal treatment agent 2.28 wt% (1.14 g) and 12.5 g of water to 50 g of fly ash B and carrying out the Environmental Agency Notification No. 13 test, elution of heavy metals was not confirmed, With this device, the necessary amount of the heavy metal treatment agent necessary for insolubilizing fly ash having an unknown heavy metal content could be determined.

It is the schematic of a heavy metal processing agent required amount determination apparatus. It is a test result using the heavy metal processing agent required amount determination apparatus in the fly ash B.

DESCRIPTION OF SYMBOLS 1 Light-receiving part 2 Laser light source part 3 Amplifier unit 4 Stirrer 5 Transparent measuring container 6 Stirrer 7 Drug injection part 8 Drug injection nozzle 9 Container top cover

Claims (4)

A detector capable of detecting turbidity change in a solution in which heavy metal is eluted from a heavy metal-containing substance (hereinafter referred to as “heavy metal solution”), and heavy metal treatment at the end point where the turbidity change is constant or the inflection point of the turbidity change In the device for determining the required amount of heavy metal treatment agent having the function of calculating the required amount of the heavy metal treatment agent from the added amount of the agent, a transparent measuring container for supplying the heavy metal solution, an agitator having the function of mixing the heavy metal solution, and turbidity from above A device for determining a necessary amount of a heavy metal treatment agent, comprising: a drug injection part that supplies a heavy metal treatment agent solution for measuring a degree of measurement; and a laser light source part and a light receiving part at a side part of the transparent measurement container. The apparatus for determining a necessary amount of a heavy metal treatment agent according to claim 1, wherein the injection port of the drug injection part is above the liquid level of the heavy metal solution. The apparatus for determining the necessary amount of heavy metal treatment agent according to claim 1 or 2, wherein the upper part of the transparent measuring container is sealed or semi-sealed. Using the apparatus according to claims 1 to 3, the heavy metal solution in the transparent measurement container is agitated, and the heavy metal treatment agent solution is continuously or intermittently supplied thereto, and laser light is emitted from the side of the transparent measurement container. A method of measuring the transmitted light intensity by irradiation and determining the required amount of heavy metal treatment agent from the degree of decrease in light transmittance (increase in turbidity).

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