JPH0235014B2 - NAMARINOKANSHIKISEISEIHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for separating valuable metals such as Sn contained in lead as soda salts, and in particular, a method for forming soda salts in the form of particles that facilitate the recovery of valuable metals from the separated soda salts. Concerning the dry refining method of lead. Various methods are used to recover valuable metals or remove impurities contained in lead, depending on the type and amount of elements contained. Generally, elements contained in lead include Cu, Te, Zn,
There are many different types such as Sn, As, Sb, Bi, Ag, and Au, and the separation methods for these elements can be roughly divided into dry methods and wet methods. The wet method is mainly an electrolytic method, and there is no difference in treatment method compared to the dry method. Various methods have been proposed for refining lead using a dry method, depending on the type of element to be removed, such as elution, oxidation, and addition of zinc, calcium, etc. Usually, Cu and Te are removed by elution first, and then
Sn, As, and Sb are removed. This Sn, As,
An oxidation method is adopted as a method for removing Sb from lead, and the Harris method is a method that accelerates the oxidation reaction by adding soda salt and recovers the removed valuable metal. The principle of the Harris method is to add caustic soda (NaOH), saltpeter (NaNO ₃ ), common salt (NaCl), etc. to molten crude lead using a Harris pot, which is designed to allow good contact between soda salt and lead. The fluidity creates a liquid molten salt layer on the top surface of the molten lead, and
It oxidizes and absorbs Sn, As, and Sb. Compared to other oxidation methods, the Harris method has advantages such as lower fuel and labor costs, no need for smoke ash treatment, and less volatilization loss. However, the valuable metal salts produced by the Harris method (hereinafter referred to as Harris salts) are extremely hard and hygroscopic when solidified by cooling, and therefore have disadvantages in storage and handling. In particular, when recovering valuable metals such as Sn contained in Harris salt, strong alkaline dust is generated during the crushing process during water extraction, and the crushing and sieving system is clogged by the moisture-absorbing parts on the surface. . The present invention solves the above-mentioned drawbacks, and makes it possible to directly produce soda salt in the form of particles that have low deliquescent properties, are easy to handle, and can be directly used for the extraction and recovery treatment of valuable metals such as Sn without being crushed. The purpose is to provide a dry refining method. According to the present invention, the sulfur content of sulfur or sulfur compounds in molten lead containing valuable metals including Sn is 0.05.
~1% by weight, and the temperature was 450~550℃.
The sodium salt of the valuable metal can be directly produced in the form of particles by adding and stirring air or an oxidizing agent and soda salt while maintaining the temperature. The present inventors have developed Pb90.5% by weight, Sn4.5% by weight, and As0.5% by weight from which most of the Cu has been removed in advance.
By adding sulfur or sulfur compounds in which the sulfur content in the crude lead has been varied in advance to molten crude lead having a composition of 4.0% by weight of Sb, for example,
Using a pot equipped with the impeller described in Publication No. 150140 and a stirrer equipped with an air suction pipe that surrounds the impeller shaft and extends directly to the impeller, approximately 500
heating to a temperature of °C and adding caustic soda at that temperature;
After stirring, Sn and As removal tests were conducted.
The amount of caustic soda added was determined according to the following formula, which is applied in the conventional Harris method. Amount of added NaOH (Kg) = 1.92 x [Amount of Sn in lead (Kg)] + 2.90 x [Amount of As in lead (Kg)] The results are shown in Figure 1 and Table 1. FIG. 1 shows an example of changes in the content of Sn, As, and Sb in the produced lead with respect to stirring time when the S content is 0.5% by weight. Although Sb hardly changed, the contents of Sn and As decreased almost linearly, indicating that Sn and As were effectively removed. Table 1 shows the relationship between the properties of the soda salt produced, the S content of crude lead, and the rotation speed of the stirrer.

[Table] ×: Not granular but liquid.
○: Particulate soda salt with a diameter of 2 to 3 mm.
According to these results, the conditions for the formation of granular soda salt depend on the stirrer rotation speed and the S content, and the higher the stirrer rotation speed, the better. It is necessary for the content to be 0.05% by weight or less in order to stably obtain granular soda salt. Moreover, if the S content exceeds 1% by weight, bulky soda salt is produced, which becomes difficult to handle, and the amount of lead included in the soda salt also increases, which is not preferable. Therefore, in order to obtain granular soda salt, an S content of 0.05 to 1% by weight is a suitable range. The sulfur compound added is SnS or PbS.
is effective and elemental sulfur may be used, but Cu ₂ S and Sb ₂ S ₃ were not effective in producing granular soda salt. The reaction temperature is 450-550℃, preferably 450℃
~500°C is suitable. Below 450°C, the removal rate of Sn, etc. is slow, and above 550°C, PbO is produced in large quantities, and excess PbO mixes with soda salt and becomes lump-like, which is unsuitable. Moreover, if the temperature exceeds 500°C, combustion will occur on the surface of the generated soda salt, so the most preferable temperature is 450 to 500°C. As the soda salt to be added, caustic soda (NaOH) is suitable if the agitator with the air suction pipe described above is used, but saltpeter (NaNO ₃ ) and common salt (NaCl) can also be used together as in the conventional Harris method. can. Incidentally, the S added at the beginning becomes Na ₂ S during the above-mentioned refining operation and is mixed into the granular soda salt, so it does not remain in the lead after refining. The granular soda salt thus produced can be scooped out with a bucket or the like and easily separated from the molten lead. This granular soda salt has no deliquescent properties, and can be recovered at a high yield by repulping it with water without pulverizing it, stirring it, solid-liquid separation, and leaching valuable metals such as Sn with water. be. As explained in detail above, according to the lead dry refining method of the present invention, lead can be purified by effectively removing valuable metals, especially Sn and As, contained in crude lead. The generated soda salt containing Sn, etc. is convenient for storage and handling as it is obtained in the form of non-deliquescent granules.
This method has a great effect in that it does not require pulverization when recovering Sn, etc. The present invention will be explained below using examples. Example 1 Pb90.5% by weight, Sn4.5% by weight, As0.5% by weight,
PbS was added to 8.5 tons of molten lead with a composition of 4.0% by weight of Sb in an amount such that the S content in the lead was 0.35% by weight, and 420kg of NaOH was added in a pot equipped with a stirrer equipped with an impeller and an air suction pipe. was added and stirred. The reaction temperature is
The pot was heated externally to 450-500°C and stirring continued for 4 hours. Stirrer rotation speed is 155rpm
And so. Sn0.25 weight as product. %, 7.5 t of lead with 0.05 wt % of As and 1.4 t of granular soda salt with 26 wt % of Sn were obtained.
The particle size of the granular soda salt floating on the molten lead is 2 to 3.
Most of the material was in the form of pellets with a diameter of mm, and could be easily separated using a bucket scraper. As a result of leaching this granular soda salt with water at a bulb concentration of 300g/, Sn77.3g/, As2.43g/,
A leachate with Sb0.03g/ and Pb<0.01g/ was obtained.
The water leaching rate of Sn was 99% or more. Further, even if the granular soda salt was left as it was for one month, it did not dissolve. Example 2 Pb90.5% by weight, Sn4.5% by weight, As0.5% by weight,
PbS was added to 55 tons of molten lead with a composition of 4.0% by weight of Sb so that the S content in the lead was 0.30% by weight, and a stirrer equipped with an impeller and an air suction pipe was installed to dissolve NaOH3 in a pot. 3t was added and stirred. Reaction temperature is 450
The pot was heated externally to ~475°C and stirring continued for 10 hours. The rotation speed of the stirrer was 155 rpm. Sn0.05 weight as product. %, 48 t of lead with 0.05 wt % of As and 10 t of granular soda salt with 24.8 wt % of Sn were obtained.
Most of the granular soda salts were pellet-like with a diameter of 2 to 3 mm. As a result of leaching this granular soda salt with water at a bulk concentration of 300g/, Sn73.7g/, As2.50g/,
A leachate with Sb0.02g/ and Pb<0.01g/ was obtained.
The water leaching rate of Sn was 99% or more. Incidentally, even when the granular soda salt was left for one month, almost no deliquescent property was observed. Example 3 Pb90.5% by weight, Sn4.5% by weight, As0.5% by weight,
SnS was added to 55 tons of molten lead with a composition of 4.0% by weight of Sb so that the S content in the lead was 0.30% by weight, and NaOH2 was added in a pot equipped with a stirrer equipped with an impeller and an air suction pipe. 8t, NaNO ₃ 0.56t and NaCl 0.93t were added and stirred. The reaction temperature was heated from the outside of the pot to 450-475°C, and stirring was continued for 9 hours.
The rotation speed of the stirrer was set to 155 rpm. Sn0.01wt%, As0.05wt% lead as product
12 tons of granular soda salt containing 47 tons and 22.7% by weight of Sn were obtained. Most of the granular soda salts were pellet-like with a diameter of 2 to 3 mm. As a result of leaching this granular soda salt with water at a pulp concentration of 300g/, Sn67.5g/, As2.40g/,
A leachate with Sb0.04g/ and Pb<0.01g/ was obtained.
The water leaching rate of Sn was over 99%. Further, even when the granular soda salt was left for one month, almost no deliquescent property was observed. Comparative example Pb91.0wt%, Sn3.5wt%, As0.30wt%,
8.5 tons of dissolved lead containing 4.0% by weight of Sb and 0.01% by weight of S was placed in a pot equipped with a stirrer equipped with an impeller and an air suction pipe, and 420 kg of NaOH was added and stirred. The reaction temperature was maintained at 450-475°C and stirring continued for 6 hours.
The rotation speed of the stirrer was 155 rpm. The generated soda salt did not become granular but remained liquid, and a mist of soda salt was scattered, resulting in a poor environment. The Sn content of the obtained lead was 1.0% by weight.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of changes in the contents of Sn, As, and Sb in lead when the lead dry refining method of the present invention is carried out.

Claims (1)

[Claims] 1 Add sulfur or sulfur compounds to molten lead containing valuable metals including Sn at a sulfur content of 0.05 to 1% by weight, maintain the temperature at 450 to 550°C, and add air or an oxidizing agent and soda salt. A method for dry refining lead, characterized in that the sodium salt of the valuable metal is produced in the form of particles by stirring and oxidizing.