JP2010222625A - Electrolytic method (2) for lead - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic method for lead, which can collect a high purity of lead even when collecting lead that is contained in a dry dust produced in a nonferrous smelting process, in a melting furnace of a raw material for recycling such as a substrate and electronic parts and in a dry bottom furnace for melting industrial waste therein, by electrolyzing lead by using an anode of a high Bi grade. <P>SOLUTION: The electrolytic method for lead collects lead of high purity by employing the high-impurity Pb anode with 5-30 mass% of the Bi grade, using a sulfamate bath containing a smoothing agent as an electrolytic solution, and setting a current density at 50 A/m<SP>2</SP>or lower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a method for recovering Pb contained in non-ferrous smelting, melting furnaces for recycled materials such as bases and electronic components, and dry smoke ash generated from a dry furnace for melting industrial waste.

In order to recover Pb contained in non-ferrous smelting dry ash from non-ferrous smelting, melting furnaces for recycling raw materials such as foundations and electronic parts, and dry furnaces for melting industrial waste, fumes are leached with sulfuric acid, After changing to lead sulfate, smelting reduction is performed in an electric furnace. In the patent document 1, Pb is recovered by electrolytic purification in a sulfamic acid bath after the metal separated by smelting reduction is soda-treated and then the metal is subjected to anode casting.

In patent document 1, when the raw material with high Bi quality in a raw material is processed, Bi quality in electric lead will become high. Therefore, it is necessary to remove Bi by electrolytic refining after casting electric lead having high Bi quality as an anode again.
Reference number T21-0201 Lead electrolysis method Patent applicant: Nikko Metal Co., Ltd.

An object of the present invention is to provide a lead electrolysis method capable of recovering high-purity lead even for a high-Bi grade anode with respect to the prior art.

The present inventors made the following invention in order to solve the above-mentioned problems.
(1) Lead electrolysis, characterized by the recovery of high-purity lead by reducing the current density to 50 A / m2 or less in electrolytic refining in a sulfamic acid bath using a high impurity anode of Bi grade 5 to 30 mass% Method.

According to the present invention,
(1) A lead electrolysis method characterized by being able to efficiently recover highly pure lead having a Bi grade of 5 massppm or less from a high Bi grade lead anode has been found.

(2) Smooth electrodeposition of the electrodeposition surface can be easily obtained.

The present invention is described in further detail below.
The raw material contains 70 to 99 mass% lead, 0.04 mass% tin, and 5 to 30 mass% bismuth in the lead-containing material of the present invention. This is because when bismuth is increased to 5 to 30 mass% in the anode, the contamination of bismuth in the electrodeposited electrode lead increases.
For example, the lead-containing material is subjected to anode casting, and electrolytic purification is performed using the anode. By making the anode size smaller than the cathode size, the edge effect can be prevented, and smooth and good electrodeposited lead can be recovered.

As the electrolytic solution, the sulfamic acid concentration is optimally 20 to 100 g / L, and the lead concentration is optimally 20 to 100 g / L.
Furthermore, smooth and good electrodeposited lead can be recovered by setting Neugen BN-1390 and / or Neugen BN-2560 to 1 to 10 mg / L as the smoothing agent.

Next, as a result of confirming the relationship between the current density and the Bi quality in the cathode, as shown in FIG. 1, if the current density is 50 A / m ² or less, the Bi quality is a low Bi quality of 5 massppm or less and smooth electrodeposition. Lead can be recovered.

(Example 1) Method for recovering low-Bi-grade electrodeposited lead As a composition of the electrolytic solution, 10 mg of Neugen BN-1390 as a smoothing agent was added to a solution adjusted to lead concentration: 80 g / L and sulfamic acid concentration: 20 g / L. Add / L.
The high-Bi grade lead anode and lead seed plate or stainless steel plate is used as the cathode, and the battery is inserted alternately.
It is optimal that the size of the cathode be about 20 to 30 mm larger than the anode because the current concentration on the edge portion can be reduced.
After the electrode is charged, the electrolytic solution is replenished in the battery case, and the concentration distribution in the battery case is made uniform by supplying the electrolyte solution so that the residence time of the electrolytic solution in the battery case is about 1 hour.
By adjusting the electrolyte temperature to 20 to 30 ° C. and then energizing it at a current density of 50 A / m 2, it is possible to recover low Bi quality electrodeposited lead with a Bi quality of 5 mass ppm or less.

Relationship between current density and Bi quality (unit: massppm) in electrodeposited lead as one aspect of the present invention

Claims (1)

Electrolysis of lead characterized in that high purity lead is recovered by reducing the current density to 50 A / m2 or less in electrolytic purification in a sulfamic acid bath using a high impurity anode of Bi grade 5 to 30 mass% .