JPS6228699B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for regenerating a chelate resin that efficiently converts an acid type chelate resin into a calcium salt type. Conventionally, regeneration of chelate resins used in the calcium salt type has been carried out in the following order: eluting heavy metals with acid, Na chlorination of the resin, and Ca chlorination of the resin, resulting in poor regeneration efficiency. Since the volume change is large, deterioration of the resin has become a problem. Therefore, the present inventors investigated a method for efficiently regenerating chelate resin, and as a result, the elution process of heavy metals with acid,
We have developed a recycling method that allows for efficient resin regeneration using only the Ca chloride process of the resin, makes it possible to omit the resin Na chloride process, which was a problem with conventional recycling methods, and also improves the durability of the resin. This heading led to the present invention. That is, the method for regenerating chelate resin of the present invention is to regenerate heavy metals such as mercury, gold, silver, platinum, copper, lead, chromium, cobalt, iron, zinc, cadmium, nickel, and tin from chelate resin with mineral acid. By treating an acid type resin, that is, an H type resin, in which heavy metal ions have been eluted and recovered, with a mixed aqueous solution of an alkaline earth metal salt and an alkali metal hydroxide, it is directly converted into a Ca salt type chelate resin. This is something that can be done. As the alkaline earth metal salt used in the present invention,
Calcium salts selected from calcium chloride, calcium nitrate, and calcium acetate are suitable, and H
This regenerates mold resin into Ca salt type resin. Calcium hydroxide may precipitate when preparing the mixed aqueous solution, but if a precipitate occurs, it is preferable to remove the precipitate by decantation, filtration, etc. before use. The above mixed aqueous solution preferably contains 0.5 to 10% by weight of calcium salt and alkali metal hydroxide in a concentration of 0.01 to 1% by weight. In addition, the main purpose of using an alkali metal hydroxide is to neutralize the acid remaining in the chelate resin that has been regenerated into H type by mineral acid washing.
The object of the present invention can be achieved if at least the alkaline compound equivalent to neutralizing the acid is contained in the mixed aqueous solution. In the chelate resin used in the present invention, the resin matrix is made of one selected from styrene-divinylbenzene resin, epoxy resin, phenol resin, vinyl chloride resin, and vinylidene chloride resin, and the chelate-forming group is an amino acid group, an imino It is a chelate resin having at least one functional group having an amino group and a carboxyl group, such as an acetate group, an iminodiacetate group, an iminopropionic acid group, and an iminodipropionic acid group. The above chelate resin can be produced by a generally known method. For example, at least one of amino acids, iminoacetic acid, iminodiacetic acid, iminopropionic acid, iminodipropionic acid
A method of obtaining a chelate resin by preparing a mixed aqueous solution of seeds, phenol, and formalin, and adding this mixed aqueous solution to a non-aqueous solvent to carry out a suspension polymerization reaction.
Lower alkyl esters of amino acids, lower alkyl esters of iminoacetic acid, lower alkyl esters of iminodiacetic acid, lower alkyl esters of iminopropionic acid, lower alkyl esters of iminodiacetic acid, methyl acrylate, methyl methacrylate, or acrylonitrile in polyalkylene polyamines. At least one of the compounds having two or more active hydrogens in one molecule and a bisepoxy compound are added to water, a suspension polymerization reaction is carried out, and the resulting resin is subjected to a saponification reaction. A method for producing a chelate resin, in which at least one of acrylic acid methyl ester, methacrylic acid methyl ester, and acrylonitrile is mixed with at least one of vinyl chloride, vinylidene chloride, styrene, and divinylbenzene, and the mixture is added to water and suspended. A method of producing a chelate resin by performing a turbid polymerization reaction and saponifying the resulting resin, and a method of producing a chelate resin by performing a chloromethylation reaction on a spherical resin of styrene-divinylbenzene with chloromethyl methyl ether. Examples include a method of producing a chelate resin by reacting a resin, or at least one of vinyl chloride resin and vinylidene chloride resin with an amino acid, iminoacetic acid, iminodiacetic acid, iminopropionic acid, iminodipropionic acid, and the like. Examples of methods for contacting the H-type chelate resin with the above-mentioned mixed aqueous solution include a batch method, a column method, etc. Further, in the column method, a circulation method, a transient method using an upward flow or a downward flow, etc. are mentioned. The water flow rate in the column method is 0.1 to 20/hr--Resin
is preferred. The present invention is not limited to these methods. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Using a Ca-type chelate resin having an epoxy resin as a base and an iminopropionic acid group and an iminodipropionic acid group as functional groups, 10 g of cadmium ion was adsorbed per resin by a batch method. Pack 50ml of this resin into a column with an inner diameter of 25mm, and pass 300ml of 0.5NHCl aqueous solution at a flow rate of 2/hr.
--Resin was passed through in a downward flow to elute and recover cadmium. Next, 150 ml of tap water was passed through the column to push out the HCl aqueous solution remaining in the column, and then 350 ml of a mixed aqueous solution containing 10% CaCl ₂ and 0.2% NaOH was passed through the column at a flow rate of 3/hr. , the liquid was passed in an upward flow. Furthermore, after removing the mixed aqueous solution remaining in the column from the bottom of the column, 100 ml of tap water was passed through the column at a flow rate of 3/hr--Resin in a downward flow to complete the regeneration of the resin. This recycled resin was removed from the column and the calcium content in the resin was measured, and the calcium content was 97% compared to before use. Example 2 Using styrene-divinylbenzene resin as a matrix,
Ca type chelate resin having iminopropionic acid group and iminodipropionic acid group as functional groups
100ml was stirred with 1NHCl1 in a beaker for 3 hours to elute calcium from the resin. The amount of calcium recovered was 20 g/-Resin. Next, this resin was thoroughly washed with water, and then stirred for 3 hours in a mixed aqueous solution of 50 g of calcium chloride and 1 g of sodium hydroxide adjusted to 500 ml with ion-exchanged water. After washing 100 ml of this resin twice with water, it was stirred with 1NHCl1 for 3 hours to elute calcium.
The amount of calcium recovered was 19.9g/-Resin
The playback rate was almost 100%. Example 3 After filling a column with an inner diameter of 80 mm with a Ca-type chelate resin 1 having a phenolic resin as a base and a glutamic acid group as a functional group, 2NHCl5 was passed through at a flow rate of 2/hr--Resin downward flow, Calcium elution was performed. By measuring the concentration of calcium ions in the eluent, the amount of eluted calcium can be determined.
It was 16.3g/-Resin. Next, after washing the resin by passing ion-exchanged water 2 under the same conditions, a mixed aqueous solution 5 containing 5% calcium chloride and 0.1% potassium hydroxide was flowed upward at a flow rate of 2/hr--Resin. It was circulated for 3 hours. After the mixed aqueous solution remaining in the column was drained from the bottom of the column, ion-exchanged water 2 was passed through the column for washing, and the regeneration was completed. Next, 2NHCl5 was applied in a downward flow at a flow rate of 2/hr-
Calcium was eluted from the resin by passing through -Resin, and the amount recovered was determined by measuring the concentration of calcium ions, which was 15.8 g/-Resin. Example 4 After filling a column with an inner diameter of 25 mm with 100 ml of a Ca-type chelate resin having an epoxy resin as a matrix and iminoacetic acid groups and iminodiacetic acid groups as functional groups, 400 ml of 2N HCl was passed through the column at a flow rate of 2/hr.
Calcium was eluted by flowing resin in a downward flow. The amount of eluted calcium is 18.1g/-
It was warm with resin. Next, 200 ml of ion-exchanged water was passed under the same conditions to wash the resin, and then 500 ml of a mixed aqueous solution containing 2% calcium chloride and 0.2% potassium hydroxide was poured in a downward flow at a flow rate of 2/hr. The liquid was passed through. Subsequently, 200 ml of ion-exchanged water was passed under the same conditions to complete the regeneration. Next, add 400ml of 2N HCl in a downward flow at a flow rate of 2/
A solution of hr--Resin was passed through the resin to elute calcium from the resin. The amount of calcium recovered is 17.9
g/-Resin, the recovery rate was 98.9%. Example 5 Using the same Ca salt type chelate resin as in Example 2, the amount of copper ions per resin was determined by the batch method.
15.4g was adsorbed. This copper ion adsorption resin 50ml
was packed in a column with an inner diameter of 25 mm, and 300 ml of 1N HCl was passed through the column in a downward flow at a flow rate of 2/hr--Resin to elute and recover copper ions. Next, 150ml of tap water
was passed through the column using SV2 to push out hydrochloric acid remaining in the column, and then 300 ml of a mixed aqueous solution containing 5% CaCl ₂ and 0.05% KOH was passed through the column using SV3 in an upward flow. Furthermore, after removing the mixed aqueous solution remaining in the column from the bottom of the column, add 2000ml of tap water.
Water was passed through SV5 in an upward flow to complete resin regeneration. This regenerated resin was taken out from inside the column and the calcium content in the resin was measured. As a result, the calcium content was 98.7% compared to the Ca type chelate resin before copper ion adsorption. Example 6 Using the same Ca salt type chelate resin as in Example 3 (Ca adsorption amount: 20.5 g/-Resin), 12 g of zinc ions were adsorbed per resin by the batch method. Add 500ml of this zinc ion adsorption resin to 1N HCl
5 in a beaker for 5 hours to elute Zn ²⁺ . Next, this resin was sufficiently washed with water, and then added to mixed aqueous solution 2 in which 300 g of calcium chloride and 5 g of sodium hydroxide were dissolved in ion-exchanged water, and stirred for 3 hours. After washing 100ml of this Ca salt type resin twice with water, add 1N HCl 1 and 3
The mixture was stirred for an hour to elute calcium. The amount of calcium recovered was 19.7g/-Resin, which was approximately 96% lower than that of Ca salt type chelate resin before zinc ion adsorption.
% reproduction rate. Example 7 50 ml of H-type chelate resin with vinyl chloride resin as the resin base and lysine group as the functional group was prepared with an inner diameter of 25 mm.
Ca by the conventional method shown below.
The chlorination method and the Ca chlorination method according to the method of the present invention were carried out, and the volumetric expansion coefficient and adsorption amount of Ca were determined for each method, and the results are shown in Table 1. The volumetric expansion coefficient can be calculated using the formula from the height A of the highest resin layer shown in a series of Ca chlorination steps (in the conventional method, the highest value was shown when Na salt was formed) and the resin height B of the H-type chelate resin. It was determined by (A/B)×100.
The amount of Ca adsorbed per chelate resin was determined from the difference in concentration between the (CH ₃ COO) ₂ Ca aqueous solution before and after passing the solution through the column.

【table】

[Table] Example 8 Ca having the resin matrix and functional groups shown in Table-1
20 ml of each salt-type chelate resin was stirred with 200 ml of 2N HCl in a beaker for 3 hours to elute calcium from the resin, and the adsorption amount of calcium C
(g/-Resin) was determined. Next, this resin was sufficiently washed with water, and then stirred for 4 hours in a mixed aqueous solution containing 35 g of calcium nitrate and 0.1 g of sodium hydroxide adjusted to 200 ml with ion-exchanged water to obtain each Ca salt type chelate resin. After washing 20ml of these resins twice with water, 2N HCl
The mixture was stirred with 200 ml for 3 hours to elute calcium. The adsorption amount D (g/-Resin) of calcium was determined from the amount of recovered calcium, and the regeneration rate was determined using the formula (D/C) x 100. The results are shown in Table 2.

【table】

Claims (1)

[Claims] 1. In a method of regenerating a chelate resin that has adsorbed heavy metals into a calcium salt type chelate resin after eluting and recovering the heavy metals with a mineral acid, (1) as a base material of the chelate resin, a styrene-divinylbenzene copolymer resin, an epoxy resin, It is made of any one of the group consisting of phenolic resin, vinyl chloride resin, and vinylidene chloride resin, and (2) the chelate-forming group bonded to the resin matrix is an amino acid, imidoacetic acid,
An acid-type chelate resin containing at least one selected from iminodiacetic acid, iminopropionic acid, and iminodipropionic acid is combined with (3) 0.01 to 1% of the hydroxide of at least one alkali metal selected from NaOH and KOH. 1. A method for regenerating a chelate resin, which comprises contacting with an aqueous solution containing 0.5 to 10% by weight of a calcium salt of any one of the group consisting of calcium chloride, calcium nitrate, and calcium acetate to form a calcium salt.