JPS63270424A - Method for refining bismuth - Google Patents

Abstract

PURPOSE:To improve the recovery rate of a bismuth product, by separating metal of high bismuth content from a bismuth-containing sediment in a furnace, by refining the above metal in a refining furnace, and by circulating the residue between a liquation furnace and the refining furnace. CONSTITUTION:A bismuth-containing sediment produced in a copper- or lead- refining stage is separated into metal containing large amounts of bismuth and white metal in a furnace. The metal is refined in a refining furnace into a bismuth product, and dross is fed into a liquation furnace. The white metal previously separated in the furnace and reduced in bismuth content is fed into the liquation furnace and heated together with the dross at 400-600 deg.C for 3-8hr. Then, eluted liquated metal containing high-concentration bismuth is returned again to the refining furnace to undergo refining.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for smelting bismuth from bismuth-containing sludge produced in a copper smelting process or a lead smelting process by a dry method.

[Conventional technology]

The conventional method of smelting bismuth from the bismuth-containing sludge produced in the copper smelting process or the lead smelting process is to smelt bismuth in a furnace using a bismuth-rich metal and bismuth-containing metal, as shown in Figure 2. Separate into a second layer with a smaller amount,
The metal was transferred to a refining process, and the second white armor was used as a raw material for another process. In this process, the first white silver is separated in the upper part and the metal is separated in the lower part in the furnace, and the first white silver contains bismuth content that has not been eluted into the metal.
This is taken out and returned to the furnace several times, and the state in which the bismuth content of the first iron is sufficiently reduced is separated as the second white slag. The metal transferred to the refining furnace produces dross (intermediate product), which is a mixture of bismuth, lead, silver, and zinc, and lysed dross with a low bismuth content. The dross is put into the refining furnace again and repeatedly melted, and the lysed dross is used as a raw material for another process together with the second white dross.

[Problem that the invention seeks to solve]

In the conventional method described above, the first white armor produced in the furnace and the dross produced in the refinement furnace are returned to the furnace and refining furnace, respectively, and melted again. This results in the process being returned to the original process,
The recovery rate of bismuth in dross is only 40 to 50%. Further, there are problems in that the work of back-melting not only increases in-process costs within the system but also puts pressure on processing capacity.

[Means for solving problems]

In the present invention, the precipitate containing bismuth generated in the copper smelting process or the lead smelting process is separated into metal containing a large amount of bismuth and metal containing a small amount of bismuth in a furnace, and then the metal is extracted. Refining is performed in a refining furnace, and the dross generated in the refining furnace is taken out and heated at 400°C or higher at 60°C along with the dross.
This is a bismuth smelting method in which heat treatment is performed at a temperature of 0° C. or lower for 3 hours or more and 8 hours or less, and the extracted drawn metal is returned to the refining furnace.

[Effect]

As shown in Figure 1, the dross separated from the furnace and the dross separated from the refining furnace are squeezed at a temperature of 400°C to 600°C in the furnace.
By heat-treating at the following temperature for 3 hours or more and 8 hours or less, bismuth is eluted at a high concentration and with a high recovery rate, taken out as drawn metal, and then returned to the refining furnace. Since the needles have a high bismuth content and are heat-treated together with dross in the drawing furnace, there is no need for the step of repeatedly returning the first needle to the furnace as in the prior art. The remaining material that is not separated and removed from the drawing furnace as drawn metal is used as slag as raw material for another process.

If the temperature of the drawing furnace is less than 400'C or the treatment time is less than 3 hours, bismuth will not be extracted sufficiently;
If the temperature of the drawing furnace exceeds 600℃ or the processing time is 8
If the time is exceeded, impurities with high melting points such as zinc and silver will increase in the molten metal, making it impossible to extract bismuth from the molten metal at a high concentration and with a high recovery rate. Since the drawn metal is made by eluting bismuth from dross and oil at high concentration and high recovery rate, it has become possible to obtain a bismuth recovery rate of 70 to 80%.

〔Example〕

Bismuth 61% by weight, lead 14% by weight, W110 heavy lid% 1
Dross (intermediate product) with a composition of 15% by weight of zinc 5
00 kg was added to the drawing furnace, and the bismuth content of the obtained molten metal was analyzed by varying the temperature and extraction time in the drawing furnace. The results are shown in Table 1.

In addition, 500 kg of dross was added to the squeezing furnace, and the processing temperature was
We measured how much bismuth in the drawn metal obtained by varying the processing time was recovered compared to the bismuth in the dross. The results are shown in Table 2.

〔Effect of the invention〕

According to the present invention, the process of returning the inner cone and dross directly to the furnace can be omitted, the residence time of bismuth in the furnace can be shortened as a whole, and the bismuth in the dross and dross can be concentrated with high concentration and high recovery rate. As a result, the recovery rate of bismuth product has been significantly improved.

[Brief explanation of drawings]

FIG. 1 is a flowchart of the present invention, and FIG. 2 is a flowchart of the prior art.

Claims (1)

[Claims] In a method of dry-smelting bismuth from bismuth-containing sludge produced in a copper smelting process or a lead smelting process, the sludge is mixed in a furnace with a metal containing a large amount of bismuth and a metal containing a small amount of bismuth. After separating and taking out each metal, the metal is purified in a refining furnace, and the dross generated in the refining furnace is taken out and heated at 400°C or higher at 60°C along with the white
A method for smelting bismuth, which comprises heating at a temperature of 0° C. or lower for 3 hours or more and 8 hours or less, and returning the eluted drawn metal to the refining furnace.