JP2009074115A - Method for producing lead sulfate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing lead sulfate where, from powder comprising lead, copper and tin such as dross generated in a lead refining stage, lead is recovered at a high recovery rate, so as to produce lead sulfate. <P>SOLUTION: While blowing oxygen or air into a nitric acid aqueous solution, powder comprising lead, copper and tin in metal form is added thereto, its pH is held to the range of 0.7 to 4.0, preferably of 1.5 to 3.5, temperature is held to 10 to 100°C, preferably to ≤50°C, oxidative leaching is performed, thereafter, it is subjected to solid-liquid separation, so as to be separated into a leaching residue comprising copper and tin and a leachate comprising lead, sulfuric acid is added to the leachate, so as to generate lead sulfate and to regenerate a nitric acid aqueous solution, subsequently, it is subjected to solid-liquid separation, the generated lead sulfate and the regenerated nitric acid aqueous solution are separated and recovered, and the regenerated nitric acid aqueous solution is used for leaching. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing lead sulfate, and more particularly to a method for producing lead sulfate from a powder containing lead and copper and tin, such as dross generated in a lead refining process.

  In the lead smelting process, copper (Cu), tin (Sn), etc. contained in the raw material are also reduced in the process of dissolving and reducing lead (Pb) raw material to produce crude lead (step in the reduction furnace). Mixed with crude lead. After the crude lead mixed with such impurities is extracted from the reduction furnace, the temperature of the crude lead is lowered to lower the solubility of copper, whereby copper is precipitated (eluted) and removed from the crude lead. At this time, depending on the concentration of tin in the lead, copper and tin form an intermetallic compound and precipitate. This deposit is in the form of powder and is generally referred to as dross.

Such dross generally has a grade of Cu 10-30%, Sn 10-30%, and Pb 30-40%, Pb is crude lead (metal in which Sn, Sb, etc. are dissolved), and Cu is an intermetallic compound with Sn. (Mainly Cu ₃ Sn), Sn exists in the form of a compound with Cu or SnO ₂ .

  As a method for separating copper from dross containing copper and tin generated in such a lead smelting process, the dross and pyrite (iron sulfide) are mixed, melted and reduced, and separated into mat and crude lead. Methods are known for separating copper concentrated therein from lead. In this method, a large amount of tin, which is an impurity in the lead smelting process, is distributed in the crude lead, so it is not possible to separate tin from lead, and it is necessary to separate tin by a method such as the Harris method or oxidation. is there.

  A method of leaching such dross with a sulfuric acid solution is also conceivable. However, when Cu and Sn form a compound, the leaching is particularly difficult, and the sulfuric acid concentration is 150 g / L and the temperature is 80 ° C. Even if oxidative leaching is performed to the extent, the Cu leaching rate is about 70%, and Sn cannot be leached as tin oxide, so that lead and tin cannot be separated. In addition, when Cu is leached, Cu can be recovered by electrolysis or substitution. However, in the case of electrolysis, the equipment burden is large, and when replacing with Fe or the like, it is necessary to treat the iron sulfate solution. .

  Also, carbonation of lead soot (lead soot containing lead, tin and bismuth) obtained by leaching of dust generated in the converter in the copper smelting process, and carbonation soot obtained (carbonation containing lead, tin and bismuth) Ii) is dissolved in nitric acid, and at that time, carbonated soot is additionally added so as to have an end point of pH 1 to 3 to produce a nitric acid solution containing lead and a nitric acid solution residue containing tin and bismuth and containing lead. The nitric acid solution is sulphated to recover the fine lead slag containing lead, the nitric acid solution residue containing tin and bismuth is dissolved in hydrochloric acid, and the hydrochloric acid solution residue containing tin is used as a tin raw material. A method of collecting has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-109939 (paragraph numbers 0007-0008)

  When the above-described dross is used as a copper raw material in an existing copper smelting facility (for example, a converter), the Pb content is large, which is not desirable, and the Pb recovery rate is extremely low. Moreover, in the method of Patent Document 1, Pb cannot be recovered at a high recovery rate from dross generated in the lead refining process. Furthermore, only Pb is selectively extracted from the above dross by an inexpensive and simple method and recovered in a desirable form as a raw material for the lead smelting process, and Cu and Sn are separated and recovered to recover Cu and Sn. It is desired to make it a convenient intermediate product.

  Therefore, in view of such conventional problems, the present invention recovers lead from a powder containing lead and copper and tin, such as dross generated in the lead refining process, at a high recovery rate by a low-cost and simple method. It aims at providing the manufacturing method of lead sulfate which can manufacture lead.

  As a result of diligent research to solve the above-mentioned problems, the present inventors conducted solid-liquid separation after leaching a powder containing lead and copper and tin such as dross generated in the lead refining process while oxidizing it in an aqueous nitric acid solution. And then separated into a leaching residue containing copper and tin and a post-leaching solution containing lead, and sulfuric acid is added to this post-leaching solution to produce lead sulfate, and a nitric acid aqueous solution is regenerated and then separated into solid and liquid. Separating lead sulfate and regenerated aqueous nitric acid solution to recover lead from a powder containing lead, copper and tin at a high recovery rate by an inexpensive and simple method to produce lead sulfate The present inventors have found that this can be done and have completed the present invention.

  That is, the method for producing lead sulfate according to the present invention comprises leaching a powder containing lead, copper, and tin while oxidizing in an aqueous nitric acid solution, followed by solid-liquid separation, and a leaching residue containing copper and tin, and a leaching containing lead. Separated into post liquor, sulfuric acid was added to the liquid after leaching to produce lead sulfate, and after regenerating the nitric acid aqueous solution, solid-liquid separation was performed, and the produced lead sulfate and the regenerated nitric acid aqueous solution were separated and recovered. It is characterized by doing.

  In this lead sulfate production method, it is preferable to use the regenerated aqueous nitric acid solution for leaching, and it is preferable to oxidize by blowing oxygen or air into the aqueous nitric acid solution. Moreover, it is preferable that the powder containing lead, copper, and tin is a powder containing lead, copper, and tin in metal form, respectively. Further, the pH of the aqueous nitric acid solution is preferably maintained in the range of 0.7 to 4.0 during leaching, and more preferably in the range of 1.5 to 3.5. Further, the temperature of the aqueous nitric acid solution is preferably maintained in the range of 10 to 100 ° C. during the leaching, and the temperature of the aqueous nitric acid solution is more preferably maintained at 50 ° C. or lower during the leaching.

  According to the present invention, lead sulfate can be produced by recovering lead at a high recovery rate from a powder containing lead such as dross generated in the lead refining process and copper and tin by an inexpensive and simple method. Further, the aqueous nitric acid solution can be regenerated during the production of lead sulfate and reused for the production of lead sulfate.

  Hereinafter, an embodiment of a method for producing lead sulfate according to the present invention will be described with reference to FIG.

  First, a dross containing Sn, Cu, and Pb generated in a dry refining process of lead smelting is prepared. This dross is preferably classified to 150 μm or less by classification with a sieve or the like.

Next, oxygen or air is blown into an aqueous nitric acid solution (leaching source solution), and dross is added while stirring, thereby leaching Pb while oxidizing the dross. In this leaching, in order to suppress decomposition of nitric acid and Cu leaching, the pH of the solution is preferably maintained at 0.7 to 4.0, more preferably 1.5 to 3.5, and the temperature of the solution is preferably The temperature is maintained at 10 to 100 ° C, more preferably 15 to 70 ° C, and most preferably 50 ° C or less. Even if the pH of the leaching end point is in the above range, if the free acidity is high in the initial stage of leaching, the decomposition of nitric acid and the elution of Cu occur, so the pH in the reaction tank is always in the above range. Is preferably maintained. In addition, a part of Sn is leached, but oxidation proceeds and eventually precipitates as SnO ₂ (Sn → Sn ²⁺ → Sn ⁴⁺ → SnO ₂ ↓). At this time, Cu eluting in the liquid is removed. Reactions that are fixed by substitution reactions also occur.

  Next, it is separated into a leaching residue (Pb dross containing Cu and Sn) and a liquid after leaching (Pb leaching solution) by solid-liquid separation.

  Next, after leaching, sulfuric acid is added to the solution to sulphate Pb, followed by solid-liquid separation, and the produced lead sulfate and the regenerated nitric acid aqueous solution can be separated and recovered. This regenerated aqueous nitric acid solution can be used for the nitric acid leaching described above.

  Thus, since only lead can be selectively leached and fixed, a lead smelting raw material with less impurities can be supplied. Further, by continuously supplying the above-mentioned dross to the recovered aqueous nitric acid solution, the pH in the reaction vessel can be maintained within a predetermined range and Pb can be leached.

  Hereinafter, the Example of the manufacturing method of the lead sulfate by this invention is described in detail.

[Example 1]
First, dross generated in the dry refining process of lead smelting was classified with a sieve to prepare dross of 150 μm or less (weight of about 70% of dross before classification). As shown in Table 1, the weight (quality) of Sn, Cu, Pb, Sb, and In in 70 g of dross obtained after classification was 16.43 g (23.47%) and 19.47 g (27, respectively). .82%), 25.36 g (36.23%), 1.05 g (1.50%), and 0.39 g (0.56%).

Then adding nitric acid to water NO ₃ ^- concentration ^{_{22.88g / L (NO 3 - 16.02g}} ) in the nitric acid aqueous solution (leach source solution) 700 mL (pH 0.7) in a flow rate 0.5 L / Oxygen was blown in for minutes, stirred with a disk turbine, 70 g of the dross was added, and leaching was performed for 120 minutes at room temperature (15 ° C.), followed by solid-liquid separation. In addition, since water | moisture content evaporated during this leaching and the amount of liquids decreased, the reduced amount of water was replenished at any time.

As shown in Table 1, the concentrations (weights) of Sn, Cu, Pb, Sb, In, and NO ₃ ⁻ contained in 700 mL (pH 1.16) of the leached solution obtained after the solid-liquid separation were each 0. 00 g / L (0.00 g), 1.62 g / L (1.13 g), 34.04 g / L (23.83 g), 0.00 g / L (0.00 g), 0.03 g / L (0. 02g) and 22.09 g / L (15.46 g), and there was a loss of 0.56 g (= 16.02-15.46 g) of NO ₃ ⁻ due to leaching.

  Further, as shown in Table 1, the weight (quality) of Sn, Cu, Pb, Sb, and In contained in 46.83 g of the leaching residue obtained after the solid-liquid separation was 16.43 g (35.08%), respectively. ), 18.34 g (39.17%), 1.53 g (3.27%), 1.05 g (2.24%), and 0.37 g (0.78%).

  Accordingly, as shown in Table 1, the distribution ratios in the leaching solution and the leaching residue of Sn, Cu, Pb, Sb, and In after solid-liquid separation are 0.0%, 100.0%, and 5.8, respectively. % And 94.2%, 94.0% and 6.0%, 0.0% and 100.0%, 6.0% and 94.0%.

Next, 11.9 g of sulfuric acid (SO ₄ ²⁻ 10.70 g) was added to the solution after leaching, and the mixture was stirred at 20 ° C. for 30 minutes, and then separated into solid and liquid.

As shown in Table 2, the concentrations (weights) of Sn, Cu, Pb, Sb, In, NO ₃ ⁻ , SO ₄ ²⁻ contained in 710 mL of the leached solution obtained after the solid-liquid separation were 0 respectively. 0.000 g / L (0.00 g), 1.52 g / L (1.08 g), 0.87 g / L (0.62 g), 0.00 g / L (0.00 g), 0.03 g / L (0 0.02 g), 22.09 g / L (15.46 g), and 0.05 g / L (0.04 g), and an aqueous nitric acid solution was obtained as a solution after leaching.

  Further, as shown in Table 2, the weight (quality) of Sn, Cu, Pb, Sb, and In contained in 35.54 g of the residue (precipitate) obtained after the solid-liquid separation was 0.00 g (0 0.000), 0.05 g (0.15%), 23.21 g (65.30%), 0.00 g (0.00%), 0.00 g (0.00%), and sulfuric acid as a residue Lead was obtained.

  Thus, in Example 1, the Pb leaching rate by the nitric acid aqueous solution was as high as 94%, the Cu elution amount was as low as 1.13 g (1.62 g / L), and the nitric acid decomposition amount was as small as 0.56 g. Further, by adding sulfuric acid to the solution after leaching, a precipitate composed of lead sulfate with few impurities and an aqueous nitric acid solution can be obtained. This aqueous nitric acid solution can be used again for dross leaching.

[Comparative Example 1]
Similarly to Example 1, dross generated in the dry refining process of lead smelting was classified with a sieve to prepare dross of 150 μm or less. As shown in Table 3, the weight (quality) of Sn, Cu, Pb, Sb, and In in 70 g of dross obtained after classification was 16.81 g (24.01%) and 17.91 g (25 .58%), 19.22 g (27.46%), 2.36 g (3.37%), and 0.30 g (0.44%).

Then adding nitric acid to water NO ₃ ^- concentration ^{_{105.02g / L (NO 3 - 73.51g}} ) in the nitric acid aqueous solution (leach source liquid) 700mL (pH-0.88) warmed to 70 ° C. Then, oxygen was blown into the aqueous solution at a flow rate of 0.5 L / min, stirred by a disc turbine, 70 g of the dross was added, and leaching was performed for 120 minutes, followed by solid-liquid separation. In addition, since water | moisture content evaporated during this leaching and the amount of liquids decreased, the reduced amount of water was replenished at any time.

As shown in Table 3, the concentrations (weights) of Sn, Cu, Pb, Sb, In, and NO ₃ ⁻ contained in 700 mL (pH 0.67) of the leached solution obtained after the solid-liquid separation were each set to 0. 00 g / L (0.00 g), 25.27 g / L (17.69 g), 26.23 g / L (18.36 g), 0.00 g / L (0.00 g), 0.05 g / L (0. 03 g) and 75.85 g / L (53.10 g), and there was a loss of 20.41 g (= 73.51-53.10 g) of NO ₃ ⁻ due to leaching.

  The weight (quality) of Sn, Cu, Pb, Sb, and In contained in 29.4 g of the leaching residue obtained after solid-liquid separation was 16.81 g (57.18%), as shown in Table 3. ), 0.22 g (0.75%), 0.86 g (2.93%), 2.36 g (8.03%), and 0.27 g (0.93%).

  Therefore, as shown in Table 3, the distribution ratios in the post-leaching solution of Sn, Cu, Pb, Sb, and In and the leaching residue after solid-liquid separation are 0.0%, 100.0%, and 98.8, respectively. % And 1.2%, 95.5% and 4.5%, 0.0% and 100.0%, 10.6% and 89.4.

  Thus, in Comparative Example 1 in which the nitric acid concentration and the leaching temperature were higher than in Example 1, the Pb leaching rate by the nitric acid aqueous solution was 95.5%, which was as high as in Example 1. However, the elution amount of Cu is 17.69 g (25.27 g / L), which is very high compared to Example 1, and the amount of nitric acid decomposition is 20.41 g, which is much higher than that of Example 1. It was.

[Comparative Example 2]
Similarly to Example 1, dross generated in the dry refining process of lead smelting was classified with a sieve to prepare dross of 150 μm or less. As shown in Table 4, the weight (quality) of Sn, Cu, Pb, Sb, and In in 70 g of dross obtained after classification was 16.95 g (24.21%), 20.24 g (28 .92%), 20.31 g (29.01%), 2.54 g (3.63%), and 0.38 g (0.55%).

Then, water was added nitric acid NO ₃ ^- concentration 14.26 g _/ ^L (NO 3 - 9.98 g) in the nitric acid aqueous solution (leach source solution) 700 mL of (PH0.54) was heated to 70 ° C., Oxygen was blown into the aqueous solution at a flow rate of 0.5 L / min, stirred with a disc turbine, 70 g of the dross was added, and leaching was performed for 120 minutes, followed by solid-liquid separation. In addition, since water | moisture content evaporated during this leaching and the amount of liquids decreased, the reduced amount of water was replenished at any time.

As shown in Table 4, the concentrations (weights) of Sn, Cu, Pb, Sb, In, and NO ₃ ⁻ contained in 700 mL (pH 2.98) of the leached solution obtained after the solid-liquid separation were each set to be 0.00. 00 g / L (0.00 g), 6.34 g / L (4.44 g), 27.02 g / L (18.91 g), 0.00 g / L (0.00 g), 0.00 g / L (0. 200 g), was 13.08g / L (9.16g), NO 3 of 0.82g (= 9.98-9.16g) by leaching ^- there is a loss.

  Moreover, as shown in Table 4, the weight (quality) of Sn, Cu, Pb, Sb, and In contained in 43.37 g of the leaching residue obtained after the solid-liquid separation was 16.95 g (39.08%), respectively. ), 15.81 g (36.44%), 1.39 g (3.21%), 2.54 g (5.86%), and 0.38 g (0.88%).

  Therefore, as shown in Table 4, the distribution ratios in the post-leaching solution of Sn, Cu, Pb, Sb, and In and the leaching residue after solid-liquid separation are 0.0%, 100.0%, and 21.9, respectively. % And 78.1%, 93.1% and 6.9%, 0.0% and 100.0%, 0.3% and 99.7%.

  Thus, in Comparative Example 2 in which the nitric acid concentration was lower than that in Comparative Example 1, the Pb leaching rate with the nitric acid aqueous solution was 93.1%, which was high as in Example 1 and Comparative Example 2. However, the elution amount of Cu was 4.44 g (6.34 g / L), which was lower than that of Comparative Example 1 but higher than that of Example 1. Further, the decomposition amount of nitric acid was 0.82 g, which was larger than that of Example 1, but was significantly reduced as compared with Comparative Example 1.

[Example 2]
The dross (Sn 25.3%, Cu 23.2%, Pb 36.8%, Sb 3.5%, In 0.4%) shown in Table 5 was prepared in the same manner as in Example 1, and the same as in Example 1. nitric acid solution (Sn0.00g / L shown in Table 5, which is reproduced by the method, Cu0.23g / L, Pb0.45g / L , Sb0.00g / L, In0.02g / L, NO 3 - 23.31g / L ) Was used as a brewing source solution, and the following dross leaching test was conducted using the leaching test apparatus shown in FIG.

  The leaching test apparatus shown in FIG. 2 includes a reaction tank 10, a stove 12 that heats the reaction tank 10, a brewing source liquid tank 14 that contains the leaching source liquid, and the leaching source liquid tank 14 to the reaction tank 10. A verista pump 16 for quantitatively supplying the brewing source liquid, a screw feeder 18 for adding dross into the reaction tank 10, a balance 20 for measuring the weight of the dross in the screw feeder 18, and a reaction tank A disk turbine 22 for stirring the solution in the reactor 10, a thermometer 24 for measuring the temperature of the solution in the reactor 10, an electrometer 26 for measuring the potential of the solution in the reactor 10, and the reactor 10 And a pH meter 28 for measuring the pH of the solution.

  First, the brewing source solution (nitric acid aqueous solution) is quantitatively supplied into the reaction vessel 10 by the verista pump 16 at a supply rate of 1100 mL / h, and the reaction is carried out by the screw feeder 18 when the pH of the solution in the reaction vessel 10 becomes 2 or less. Dross is supplied into the tank 10 at a supply rate of 147 g / h, the pH in the reaction tank 10 is maintained in the range of approximately 1.9 to 2.5, and the temperature is maintained at 35 ° C., and the reaction tank 10 is used as an oxidizing agent. The leaching test was conducted with continuous reaction by blowing air. The amount of liquid in the reaction tank 10 was maintained at about 2.5 L, and the brewing source liquid was continuously supplied so that the residence time was about 2.3 hours.

Table 5 shows the concentrations of Sn, Cu, Pb, Sb, In, and NO ₃ ⁻ in 1100 mL of the leaching solution discharged from the reaction vessel 10 between 3 hours and 4 hours after the start of the leaching test. Thus, it is 0.00g / L, 0.01g / L, 41.14g / L, 0.01g / L, 0.02g / L, 23.14g / L, respectively, and Sn in the leach residue 87.12g As shown in Table 5, the grades of Cu, Pb, Sb, and In were 42.1%, 36.9%, 3.2%, 5.0%, and 0.4%, respectively.

  Although a strict balance could not be obtained because of the continuous test, the Pb quality of the leaching residue was reduced to about 3%, and the Pb leaching rate was about 95%. Moreover, it can be seen that the Cu concentration in the solution after leaching is lower than the Cu concentration in the leaching source solution, and cemented by Pb or Sn which is lower than Cu.

[Example 3]
The dross (Sn 25.3%, Cu 23.2%, Pb 36.8%, Sb 3.5%, In 0.4%) shown in Table 6 was prepared in the same manner as in Example 1, and the same as in Example 1. nitric acid solution (Sn0.00g / L shown in Table 6, which are reproduced by the method, Cu0.05g / L, Pb0.46g / L , Sb0.01g / L, In0.00g / L, NO 3 - 58.59g / L ) As the leaching source solution, the brewing source solution (nitric acid aqueous solution) supply rate into the reaction tank 10 is 1230 mL / h, the dross supply rate is 351 g / h, and oxygen is used as the oxidant. A dross leaching test was conducted in the same manner as in Example 2 except that the residence time of the brewing source liquid continuously supplied into the tank 10 was about 2.0 hours.

Table 6 shows the concentrations of Sn, Cu, Pb, Sb, In, and NO ₃ ⁻ in 2300 mL of the leaching solution discharged from the reaction tank 10 between 3 hours and 4 hours after the start of the leaching test. Thus, it is 0.00g / L, 0.39g / L, 92.10g / L, 0.01g / L, 0.01g / L, 58.16g / L, respectively, and Sn in the leach residue 207.7g. As shown in Table 6, the grades of Cu, Pb, Sb, and In were 42.0%, 34.0%, 2.9%, 5.2%, and 0.4%, respectively.

When Pb is leached with nitric acid and the aqueous nitric acid solution is regenerated from the leachate, it is possible to leach Pb even if the pulp concentration PD is increased. Get higher. For example, the concentration of NO ₃ ⁻ in a nitric acid aqueous solution regenerated by adding sulfuric acid to a solution after leaching obtained by leaching under conditions such that the Pb concentration of the solution after leaching is about 100 g / L is 60 g / L. It becomes about L. When dross leaching is carried out batchwise using such an aqueous nitric acid solution, the initial acid concentration is high, which causes the decomposition of nitric acid and the elution of Cu, which is not convenient. In order to eliminate such inconvenience, it is necessary to carry out the reaction while controlling the supply amounts of the brewing source liquid and the dross so that the pH in the reaction vessel 10 is maintained within a predetermined range as in the second embodiment. .

  In Example 3, the initial acid concentration was thus increased, but the Pb leaching rate was high as in Example 2, and both the nitric acid decomposition amount and the Cu elution amount were slight. Moreover, since the acid concentration of the leaching source liquid to be supplied was increased, the processing amount per unit volume and unit time could be increased.

[Example 4]
Dross of 150 μm or less obtained by classifying dross generated in the dry refining process of lead smelting with a sieve (Sn 18.55%, Cu 30.75%, Pb 38.45%, Sb 3.34%, In 0.25%) Add 50 g to 500 mL of water, stir while blowing oxygen, add aqueous nitric acid so that the pH is 0.5, 1.0, 2.0 and 3, respectively, and perform leaching at 35 ° C. for 30 minutes It was. Similarly, an aqueous nitric acid solution was added so that the pH was 0.5, 1.0, 1.5, 2.0, and 3.5, respectively, and leaching was performed at 70 ° C. for 30 minutes. Table 7 shows the leaching rate when leaching at 35 ° C., and Table 8 shows the leaching rate when leaching at 70 ° C. Further, FIG. 3 shows the Pb leaching rate and Cu leaching rate when leaching at 35 ° C. and 70 ° C., and FIG. 4 shows the Sn leaching rate and In leaching rate.

  As shown in Tables 7 and 8 and FIG. 3, the Pb leaching rate was sufficiently high at pH 0.5 to 3.5 in both cases of leaching at 35 ° C. and leaching at 70 ° C. Further, when leaching at 35 ° C., the Cu leaching rate is sufficiently low at H 1.0 to 3.5, and when leaching at 70 ° C., the Cu leaching rate is sufficiently low at pH 1.5 to 3.5. It was. From these results, in order to increase the Pb leaching rate and lower the Cu leaching rate, it is preferable to adjust the pH to 1.0 to 3.5 when leaching at 35 ° C., and when leaching at 70 ° C. It is understood that the pH is preferably 1.5 to 3.5. In addition, as shown in Table 7, Table 8, and FIG. 4, the Sn leaching rate was low at pH 2.0 to 3.5 in both cases of leaching at 35 ° C. and leaching at 70 ° C.

It is process drawing which shows embodiment of the manufacturing method of lead sulfate by this invention. It is a figure which shows roughly the leaching test apparatus used in Example 2. FIG. It is a graph which shows the Pb leaching rate at the time of leaching at 35 degreeC and 70 degreeC in Example 4, and Cu leaching rate. It is a graph which shows Sn leaching rate at the time of leaching at 35 degreeC and 70 degreeC in Example 4, and In leaching rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reaction tank 12 Stove 14 Leaching source liquid tank 16 Verista pump 18 Screw feeder 20 Balance 22 Disc turbine 24 Thermometer 26 Electrometer 28 pH meter

Claims (8)

The powder containing lead, copper and tin is leached while oxidizing in an aqueous nitric acid solution, and then separated into solid and liquid, and separated into a leaching residue containing copper and tin and a leaching solution containing lead. To produce lead sulfate and regenerate the nitric acid aqueous solution, then separate the solid and liquid, and separate and recover the produced lead sulfate and the regenerated nitric acid aqueous solution. . The method for producing lead sulfate according to claim 1, wherein the regenerated aqueous nitric acid solution is used for the leaching. The method for producing lead sulfate according to claim 1 or 2, wherein the oxidation is performed by blowing oxygen or air into the aqueous nitric acid solution. The method for producing lead sulfate according to any one of claims 1 to 3, wherein the powder containing lead, copper, and tin is a powder containing lead in a metal form, copper, and tin, respectively. The method for producing lead sulfate according to any one of claims 1 to 4, wherein the pH of the aqueous nitric acid solution is maintained in the range of 0.7 to 4.0 during the leaching. The method for producing lead sulfate according to any one of claims 1 to 4, wherein the pH of the aqueous nitric acid solution is maintained in the range of 1.5 to 3.5 during the leaching. The method for producing lead sulfate according to any one of claims 1 to 6, wherein the temperature of the aqueous nitric acid solution is maintained in the range of 10 to 100 ° C during the leaching. The method for producing lead sulfate according to claim 7, wherein the temperature of the aqueous nitric acid solution is maintained at 50 ° C. or lower during the leaching.

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