JPS6227329A - Method for controlling substitution reaction of sulfide with copper ion - Google Patents

Abstract

PURPOSE:To control the titled substitution reaction by simple operation independently of a change in the composition of sulfide by regulating the oxidation- reduction potential of a slurry at the outlet of a reactor so as to keep the concn. of copper ions in the slurry at a prescribed value during the reaction. CONSTITUTION:A slurry contg. sulfide and an aqueous soln. having a prescribed copper ion concn. are poured into a slurry tank 1 and mixed by stirring to prepare a slurry as starting material. This slurry is poured into a substitution reaction tank 3 provided with an overflow pipe 4, an oxidation-reduction electrode 5, a stirrer 6 and a copper ion feeding pipe 7. While the slurry is kept at a prescribed temp. and stirred for a prescribed time, an aqueous soln. having a prescribed copper ion concn. is added to the slurry from the pipe 7 and brought into a substitution reaction. The oxidation-reduction potential of the slurry is always measured with the electrode 5 at the outlet of the tank 3 and the amount of copper ions added is increased or decreased according to the measured value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an improvement of the conversion reaction method in which a sulfide slurry and copper ions are brought into contact with each other to precipitate copper sulfide and ionize elements bonded to sulfur. It is related to.

[Conventional technology]

Conventionally, when performing a substitution reaction between sulfide and copper ions, the quality of the raw material sulfide and the concentration of copper ions are analyzed in advance, and the amount of each added is determined.At the same time, the concentration of copper ions in the aqueous solution after the reaction is determined. The method used was to analyze the amount of copper ions and adjust the amount of copper ions added.

In addition, in order to carry out this substitution reaction efficiently, it is preferable to react the sulfide and an aqueous solution containing copper ions in a countercurrent multistage system, but this is also complicated and requires frequent analysis. Another drawback was that sufficient control was difficult.

[Problem that the invention seeks to solve]

The object of the present invention is to provide a method for managing the substitution reaction between sulfide and copper ions without the above-mentioned drawbacks.

[Means for solving problems]

The method of the present invention maintains the copper ion concentration in the final reaction solution at a predetermined value by controlling the oxidation-reduction potential of the slurry at the outlet of the reaction vessel when carrying out the above-mentioned substitution reaction. The purpose of this method is to stably carry out the substitution reaction without being affected by changes in the composition of the substance.

[Effect]

In the present invention, the target sulfide is, for example, As
S % ZnS % N15s Co55 Na S
-, HS, etc., and these sulfides (hereinafter abbreviated as MS)
The substitution reaction formula between and copper ion (C+u”) is M S −
It is expressed as 1-Cu+2-OuS+M+2 and takes advantage of the fact that the CuS produced is very stable.

In order to carry out the above-mentioned substitution reaction sufficiently and to minimize the amount of copper ions used, it is necessary to maintain the feed ion concentration at an appropriate value after the reaction is completed.

As a result of various studies, the inventors of the present application found that the redox potential of a slurry of sulfides and copper ions has a strong correlation with the copper ion concentration of the filtrate of the slurry.

As a result, when various sulfide slurries are added with an appropriate copper concentration, for example, an aqueous copper sulfate solution (Ou -50 to 100 v'l) and allowed to forget for a predetermined period of time, the redox potential of the slurry is measured after the reaction is completed. The copper concentration of the slurry filtrate can be immediately determined.

The redox potential is measured using a normal redox electrode (Pt/A
, g -Ag(!l) can be used to obtain accurate values in the slurry state.

Therefore, by arranging the arrangement as shown in the flowchart in Fig. 1 so that the potential can be constantly measured, and increasing or decreasing the amount of copper ions added while knowing the redox potential using the redox electrode 5 at the outlet of the displacement reaction tank 3, the raw material Even if the composition of a certain sulfide varies, the copper concentration of the slurry filtrate can be continuously maintained at a constant value.

The residence time in the displacement reaction tank varies depending on the type of sulfide, but it is usually about 3 hours.

〔Example〕

Examples will be described below.

Example 1 Copper sulfate prepared with 50 precipitates shown in Table 1 containing arsenic sulfide obtained by treating copper flue gas cleaning solution with sulfide and a reagent grade 1 containing 80 g/l as O. Aqueous solution 1001 was placed in a raw material slurry tank 1 and mixed with a propeller type stirrer to obtain a raw material slurry. This slurry was prepared with an overflow pipe 4 with an effective capacity of 10 t,
101 was placed in a displacement reaction tank 3 in which a oxidation-reduction electrode 5, a stirrer 6, and a copper ion supply pipe 7 were set near the overflow pipe 4, maintained at 65 r with a steam pipe, and heated with a propeller-type stirrer for 3 hours. While performing light stirring, the above-mentioned copper sulfate aqueous solution containing 80 g/N of Cu+2 was added from the copper ion supply pipe 7 to bring the oxidation-reduction potential to 2.
The voltage was adjusted to 30 mV.

Table 1 Next, about 55 mg of slurry in tank 1 of the raw material slurry, which is kept at the same temperature as the slurry in reaction tank 3 by a steam pipe, is continuously fed to the displacement reaction tank per minute, and the residence time is 3. At the same time, the same copper sulfate aqueous solution is added from the copper ion supply pipe 7 so as to bring the redox potential to a predetermined value. A small amount of the filtrate was sampled and filtered by suction before entering the test, and the copper concentration was measured by atomic absorption spectrometry.

The results are shown in Table 2 and Figure 2. Oxidation-reduction potential (hereinafter referred to as OR
(abbreviated as P) and the copper ion concentration.

As is clear from Table 2 and Figure 2, there is a strong correlation between the ORP value and the copper ion concentration, and by controlling the ORP value of the slurry by adding copper ions, the final reaction solution always has a predetermined copper concentration. I was able to get

Example 2 Zinc sulfate, a first class reagent, and nickel sulfate, a first class reagent, were each dissolved in water, and 1.5 equivalents of each of sodium bisulfide, a first class reagent, was added and stirred, and the precipitate formed was sucked. Solid-liquid separation was performed by a filtration method to obtain the sulfides shown in Table 3.

Table 3 (% by weight) The sulfides in Table 3 were mixed by adding 100% of the copper sulfate used in Example 1 to a concentration of 7.6 g/l as Cu+2, which was diluted to about 171%. It was made into a raw material slurry.

The copper sulfate aqueous solution added in the displacement reaction tank was 80 g/! as Ou+2 as in Example 1. The ORB value was varied in the same manner as in Example 1, except that the initial ORP value was adjusted to 62 mV for znS and 103 mV for NiS, and the temperature of the displacement reaction tank was 60 C. The Cu concentration of the final reaction solution was analyzed.

The results are shown in FIGS. 3 and 4.

As can be seen from the figure, both ZnS and NiS are similar to Example 1.
Similar results were obtained.

〔Effect of the invention〕

When performing a substitution reaction by adding copper ions to a sulfide slurry, read the ORP value of the slurry at the outlet of the reaction tank, and add the required amount of copper ions to obtain a final reaction solution with a predetermined copper concentration. is obtained, the substitution reaction can be continuously managed for a long time without being affected by changes in the sulfide composition, etc., and without the need for the complicated work of measuring the copper concentration each time.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an apparatus for carrying out the method of the present invention, and FIG.
The figure shows the relationship between the redox potential (horizontal axis) and the copper ion concentration (vertical axis) when arsenic sulfide is replaced with copper ions, Figure 3 is with zinc sulfide, and Figure 4 is where nickel sulfide is replaced with copper ions. be. 1... Raw material slurry tank, 2... Pump, 3... Substitution reaction tank, 4... Overflow pipe, 5... Redox electrode,
6. Stirrer, 7. Copper ion supply pipe, 8. Displacement slurry receiver tank.

Claims (1)

[Claims] (1) A sulfide of an element that has a weaker bonding force with sulfur ions than a copper ion is brought into contact with a copper ion, the element bonded to sulfur in the sulfide is dissolved, and the sulfur is bonded with the copper ion. In the substitution reaction that produces a precipitate, the redox potential at the outlet of the mixed slurry of the aqueous solution containing copper ions and the sulfide is adjusted to a predetermined value by adjusting the amount of copper ions added. A method for managing a substitution reaction between sulfide and copper ions, characterized by maintaining the copper concentration of the final reaction solution obtained by solid-liquid separation at a desired value.