JPS61270215A - Production of barium salt having high purity - Google Patents

Abstract

PURPOSE:To obtain a Ba salt having high purity and suitable for electronic material, etc., easily, by treating a Ba salt soluble in hydrochloric acid with excess hydrochloric acid to give free hydrochloric acid having a specific concentration after treatment, and subjecting the system to solid-liquid separation, thereby removing Sr, Ca, etc., which are hardly separable from Ba. CONSTITUTION:A Ba salt soluble in hydrochloric acid [e.g. BaCO3, Ba(OH)2, BaS, etc.] is stirred for 1 - several hours in excess hydrochloric acid having a concentration of >=15wt%, and reacted until the free hydrochloric acid concentration in the aqueous solution reaches 40-400g/l after the reaction. The solid is separated from the liquid by suction filtration, etc., and the resultant precipitate is dried.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is directed to the production of barium salt with good purity, particularly barium salt suitable for electronic materials, etc., from which strontium and calcium, which are difficult to separate from barium, are efficiently removed. It is about the method.

[Conventional technology]

In recent years, demand for various barium salts has been increasing in the electronic parts sector such as high dielectric materials and the ferrite materials sector such as barium ferrite.゛Conventionally, the method for separating strontium and calcium from barium salt is /)
The above metal salts, etc. are dissolved in chromic acid, and the difference in solubility of chromate salts in water is utilized. 2) Methods such as applying the ion exchange resin method are used as analytical methods.

However, method 1) uses a large amount of expensive dichromate, and there are difficulties in subsequent wastewater treatment. Method 2) has drawbacks such as difficulty in separating high concentrations of barium, strontium, etc. and poor efficiency.

In addition to these methods, a method can be considered in which barium, strontium, etc. are converted into nitrates and separated based on the difference in solubility in water, but this method is not practical because most of the strontium is co-precipitated.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a method for producing barium salt with good purity without the above-mentioned drawbacks.

[Means for solving problems]

The present invention provides barium salts soluble in hydrochloric acid, such as Ba0O
, Ba(OH), BaS, etc. are treated with hydrochloric acid in an amount such that the concentration of free hydrochloric acid in the aqueous solution after treatment with hydrochloric acid becomes a predetermined value, barium is selectively separated as a precipitate, and barium with good purity is obtained. It is the source of salt.

That is, when adding hydrochloric acid to a roasted product obtained by roasting barite, which is soluble in hydrochloric acid, in a reducing atmosphere, the concentration of free hydrochloric acid in the extract after the reaction is in the range of tto -ttθOg/l. The method involves stirring at room temperature for one to several hours using excess hydrochloric acid so that the resulting precipitate is separated.

[Effect]

In the method of the present invention, raw materials containing -Ea, 5r)Oa, etc. are preferably stirred using hydrochloric acid of 75% by weight or more, and the concentration of free hydrochloric acid after the reaction is adjusted to 1Io g7 or more, 1
The reason for limiting it to 100 g/l or less is that the hydrochloric acid concentration is tt
This is because when the amount is less than 0 g/, hardly any barium chloride (Ba11.aO) precipitates are formed, and when it is more than tioo get, strontium is also co-precipitated, reducing the purity of barium.

At this time, strontium, calcium, etc. each generate chloride as well as barium, but at the above free hydrochloric acid concentration, a part or almost all of them are dissolved in the processing liquid.

Therefore, the free hydrochloric acid concentration of the treated solution depends on the purpose:
For example, if it is necessary to prevent the contamination of impurities as much as possible, the concentration of the hydrochloric acid should be as dilute as possible, and if it is desired to increase the primary yield of barium even if some impurities are mixed in, the acid concentration should be increased. Under suitable conditions, 5rsOa, which is the most difficult to separate from B&, can be separated at a removal rate of 5% by weight or more of Polygonum.

In this case, the direct yield of Ba is about 70% by weight, but since the mother liquor separated in this way can be reused repeatedly by supplementing with a predetermined amount of concentrated hydrochloric acid, the overall actual yield is 90% by weight.
That's all.

Ba1l-2HO obtained in the present invention can be dissolved in ionized water and then added with sodium hydroxide to produce barium hydroxide, sodium carbonate to produce barium carbonate, or metathesized with sodium nitrate to produce barium nitrate, etc. Srs.
It can be easily produced as it contains almost no Oa.

〔Example〕

Examples will be described below.

Example 1 96.0% by weight (hereinafter abbreviated as %) of BaSO4,/,2
barite powder containing % srs', 1% Oa;
37.7% B obtained by mixing and roasting powdered coke
a, 0.19% 5rXQ, 01% Ca, balance S
, Si, etc., were added to 00 ml of a 7% by weight (/63 g/l) hydrochloric acid aqueous solution, and the mixture was lightly stirred with a propeller stirrer at room temperature for 7 hours.

After stirring was completed, the mother liquor was separated using a suction filter (do not wash with water) The resulting precipitate was dried and weighed, and the main components were analyzed by chemical analysis. The result is the first
Shown in the table. In addition, the free hydrochloric acid of the mother liquor was bOg/l.

As can be seen from Table 1, 5rsOa, which is an alkaline earth metal like Ba, was removed to a sufficiently satisfactory extent.

Example 200.0g of the roasted material used in Example/ was 30% by weight.
Ba was precipitated in the same manner as in Example except that the sample was treated with 00 ml of an aqueous solution of (3 tit, g/l) hydrochloric acid.

The free hydrochloric acid concentration in the separated mother liquor is 200 g/l,
A precipitate (ago, ogc (dried)) was obtained.

The results are shown in Table 2.

Table 2 When the concentration of hydrochloric acid approached tioo gyt, the yield of Ea improved, but the impurity removal rate decreased slightly to gθ%.

Example 3 69.1% Ba, 22% F3r, 0.03%
A 30% by weight (31 g,/l) hydrochloric acid aqueous solution g00r
Ba precipitate was obtained in the same manner as in Example except that the treatment with nl was performed.

The concentration of free hydrochloric acid in the separated mother liquor is soo gyt,
A precipitation rating of λ, Og (dry) was obtained.

The results are shown in Table 3.

Table 3 As can be seen from Table 3, the direct yield of barium and the removal rate of calcium were satisfactory, but the removal rate of strontium remained at about 0%.

From this result, it can be seen that in order to achieve a removal rate of alkaline earth metal impurities of 90% or more in seven treatments, it is preferable to use hydrochloric acid with a concentration of about 20% by weight.

〔Effect of the invention〕

When trying to obtain barium salt with good purity, Sr, Ca, etc., which are difficult to separate from barium because they are homologous, can be efficiently separated and removed by simple operations.

Claims (1)

[Claims] (1) Barium salt soluble in hydrochloric acid is treated with the necessary amount of hydrochloric acid so that the concentration of free hydrochloric acid in the aqueous solution after treatment with hydrochloric acid is 40 to 400 g/l, and then solid-liquid separation A method for producing barium salt with good purity.