JP2006257540A - Method for treating raw zinc material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly precipitate silica in a form of being easily solid-liquid separated, which has eluted into a sulfuric acid solution while a raw zinc material is treated with the sulfuric acid solution in a wet zinc-smelting process. <P>SOLUTION: The method for treating the raw zinc material in the wet zinc-smelting process comprises the steps of: preparing a leaching solution by mixing a liquid part of an electrolysis tail liquid with an iron-removed residual solution; adding one or more substances selected from bismuth oxide, titanium oxide, antimony oxide, tin oxide, gallium oxide, cadmium oxide, calcium phosphate, phosphoric oxide, calcium fluoride, lead oxide, palladium, silver oxide, silver, iron oxide and manganese oxide into the leaching solution; subsequently charging a specified amount of a burnt raw zinc material into the leaching solution; leaching the burnt raw zinc material; and after the leaching has been finished, adding a flocculant into the obtained leaching solution to separate eluted silica and the like in a form of slurry. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a zinc raw material wet treatment process in a wet zinc smelting process, and more particularly to a zinc raw material treatment method for improving the sedimentation and filterability of silica after leaching the zinc raw material with a sulfuric acid acidic solution.

Conventionally, wet zinc smelting ore mainly composed of ZnS (zinc sulfide) is used as a zinc raw material, and a roasted product of the zinc raw material is leached using a sulfuric acid acidic solution, and the obtained leachate is solid-liquid. After separating and removing the zinc leaching residue, the liquid is further purified, and electrolytic zinc is obtained from the liquid portion through electrowinning. At this time, if there are many impurities in the ore, various problems occur in the operation of the zinc smelting process.
For example, when the zinc raw material contains a large amount of Fe (iron) or Si (silicon) as impurities, the sedimentation property of the zinc leaching residue generated after leaching of the roasted product is deteriorated. In particular, when the impurity is silica, which is a Si compound, the silica gels as the content increases, and is entangled with the zinc leaching residue, so that the sedimentation and filterability in the solid-liquid separation step are remarkably deteriorated. Then, in order to improve the sedimentation property and filterability in the said solid-liquid separation process, the proposal including patent document 1 is made.

Japanese Patent No. 3464602

  For example, in Patent Document 1, in order to improve the sedimentation property and filterability in the solid-liquid separation step, the solubility in a predetermined amount or more is determined according to the amount of silica in the composition in the acid dissolution tank in which leaching is performed in the leaching step. It is proposed to supply silica or zinc leaching residue containing silica to the dissolution tank.

  However, when the present inventors examined, even if it supplies a predetermined amount or more of soluble silica to the dissolution tank according to the amount of silica in the composition in the acid dissolution tank in the leaching step, the solid-liquid separation step The improvement in the sedimentation and filterability of silica was not satisfactory.

  The present invention has been made to solve the above-mentioned problems, and is a zinc raw material that improves the sedimentation and filterability of silica in a solid-liquid separation process without complicating the process and extending the leaching time. It is to provide a processing method.

  As a result of trial and error, the present inventors have continued intensive research to solve the above-mentioned problems, and as a result, the Pb (lead) / Ag (silver) residue produced in the zinc smelting process into the sulfuric acid solution used in the leaching process. It has been found that when the leaching is carried out after the addition of the silica, the sedimentation and filterability of silica are improved in the solid-liquid separation step. The present inventors have continued research on this knowledge as a starting point, and when an acidic sulfuric acid solution to which various substances such as Bi oxide (bismuth oxide) are added is used, solidification occurs due to coprecipitation or anchor effect. The present invention was completed by finding that the settling and filtering properties of silica were improved in the liquid separation step.

The first means for solving the above-mentioned problem is
In the wet zinc smelting process to extract zinc from zinc raw materials,
When leaching the roasted zinc raw material using sulfuric acid acidic solution, bismuth oxide, titanium oxide, antimony oxide, tin oxide, gallium oxide, cadmium oxide, calcium phosphate salt, phosphorus oxide, calcium fluoride, Leaching is performed using a sulfuric acid acidic solution to which one or more additives selected from lead oxide, lead sulfate, lead sulfide, palladium, silver oxide, silver, iron oxide, and manganese oxide are added. This is a method for treating a zinc raw material.

The second means is
The method for treating a zinc raw material according to the first means, wherein hematite produced from the wet zinc smelting step is used as the iron oxide.

The third means is
Mn starch produced from the wet zinc smelting step is used as the manganese oxide, the zinc raw material treatment method according to the first means.

The fourth means is
As the bismuth oxide and / or silver,
The zinc raw material treatment method according to the first or second means, characterized in that it uses Bi dense iron and / or lead electrolytic slime produced from a lead smelting process and containing Bi or Ag in an amount of 3 wt% or more. is there.

The fifth means is
The zinc raw material treatment according to any one of the first to fourth means, wherein one or more of the additive substances are added and an acidic sulfuric acid solution containing 0.02 g / L or more of the additive substance is used. Is the method.

The sixth means is
The zinc raw material treatment method according to the first means, wherein Bi ₂ O ₃ is used as the additive substance and 4 g / L or more is added to the acidic sulfuric acid solution.

The seventh means is
The zinc raw material treatment method according to the first means, characterized in that Bi gypsum produced from a lead smelting step is used as the additive substance and 4 g / L or more is added to the sulfuric acid acidic solution.

The eighth means is
The zinc raw material treatment method according to the first means, wherein lead electrolysis slime produced from a lead smelting step is used as the additive substance, and 1 g / L or more is added to the sulfuric acid acidic solution.

The ninth means is
The zinc raw material treatment method according to any one of first to eighth means, wherein the pH of the sulfuric acid acidic solution before the leaching is 1.5 or less.

The tenth means is
The zinc raw material treatment method according to any one of the first to ninth means, wherein a time for leaching the zinc raw material is 10 minutes to 5 hours.

  According to the method for treating a zinc raw material according to any of the first to tenth means described above, in the solid-liquid separation step after leaching the zinc raw material with a sulfuric acid acidic solution, the silica contained in the zinc raw material The solid component containing was easily separated from the liquid component and precipitated.

An embodiment of the present invention will be described with reference to FIG. 1 which is an example of a processing flow of a zinc raw material in a wet zinc smelting process.
As shown in FIG. 1, a zinc raw material such as zinc ore is first roasted and pulverized, but the pulverization is performed before and after leaching and becomes a pulverized product. To this pulverized product, a sulfuric acid-based leachate containing a liquid portion of the electrolytic tail liquor described later and a mixture of the post-deironation solution is added, and after the first leaching operation, a solid-liquid separation step is performed to obtain a liquid leachate and a solid. Get the zinc leaching residue. Next, the leaching solution is subjected to electrolytic treatment after the liquid purification operation to obtain electrozinc and electrolytic tail solution. The electrozinc is sent to the next step of zinc smelting, but the electrolytic tail solution is recycled after the solid-liquid separation step, and the liquid portion is circulated and used as the above-described leachate, and the solid portion becomes Mn starch.

On the other hand, in the zinc leaching residue described above, for example, after performing a secondary leaching operation using SO ₂ (sulfur dioxide), a solid-liquid separation operation is performed to obtain a liquid secondary leaching solution and a solid Pb / Ag residue. Get. Calcium carbonate is added to the secondary leaching solution for neutralization by one step, and after the solid-liquid separation step, a liquid one-step neutralization solution and a solid one-step gypsum are obtained. Zinc powder is added to this one-stage neutralized solution to carry out a dearsenic operation to obtain a liquid dearsenic solution and a solid RT residue. Here, RT residue is an abbreviation for Residue Treatment, which is a copper / arsenic compound containing Cu ₃ As as a main component. Calcium carbonate is added to this dearsenic solution to carry out two-step neutralization, and after the solid-liquid separation step, a liquid two-step neutralization solution and a solid two-step gypsum are obtained. This two-stage neutralized solution is added with O ₂ / steam for deironing treatment to obtain a liquid after iron removal and solid hematite. The obtained iron-free post-recycle is circulated and used as a leachate together with the liquid portion of the electrolytic tail solution described above.

At this time, if the initial zinc raw material contains a large amount of SiO ₂ (silica), the SiO ₂ becomes ZnSiO ₃ and dissolves in the leachate when the zinc roast is leached, and the pH of the leachate is reduced. As it rises, it precipitates and gels, deteriorating the sedimentation and filterability of the zinc leaching residue during the solid-liquid separation process. Here, in order to maintain good sedimentation of the zinc leaching residue during the solid-liquid separation step, it is preferable that the SiO ₂ quality in the original zinc raw material is 1% or less, but if it is more than that This results in poor sedimentation and poor filterability in the zinc leaching residue. However, the SiO ₂ content in the original zinc raw material varies and may exceed 2%.

When such a zinc raw material containing a large amount of SiO ₂ is used, the sedimentation / filterability of the zinc leaching residue during the solid-liquid separation process is poor. For example, the sedimentation evaluation performed in Example 1 described later is performed. According to the results, the sedimentation distance after 1 minute was 12 mm, and the filtration rate was 1.75 l / m ² / min. Here, when 10 g / L (about 10,000 ppm) of the above-mentioned Pb · Ag residue was added to the leachate, the sedimentation distance after 1 minute was improved to 39 mm and the filtration rate to 3.13 l / m ² / min. Next, when 10 g / L of the above Mn starch was added to the leachate, the sedimentation distance after 1 minute was improved to 27 mm and the filtration rate to 6.45 l / m ² / min. Furthermore, when 10 g / L of the above-mentioned hematite was added to the leachate, the sedimentation distance after 1 minute was improved to 22 mm and the filtration rate to 5.32 l / m ² / min. Based on these findings, we searched for substances that can improve the sedimentation and filterability of zinc leaching residue by adding to the leachate. Bismuth oxide (BiO, Bi ₂ O ₃ , and their mixtures) , Titanium oxide (TiO ₂ ), antimony oxide (Sb ₂ O ₃ ), tin oxide (SnO ₂ ), gallium oxide (Ga ₂ O ₃ ), cadmium oxide (CdO), calcium phosphate (Ca ₃ ( PO ₄ ) ₂ ), phosphorus oxide (P ₂ O ₅ ), calcium fluoride (CaF ₂ ), lead oxide (PbO ₂ ), lead sulfate (PbSO ₄ ), lead sulfide (PbS), palladium (Pb) powder, Silver oxide (AgO), silver (Ag) powder, iron oxide (Fe ₂ O ₃ ), and manganese oxide (MnO ₂ ) were found. And, by adding one or more substances selected from these substances to the leaching solution and then performing the leaching operation of the zinc raw material, the sedimentation property of the zinc residue in the solid-liquid separation process of the zinc leaching residue, The filterability could be improved.

Here, the above-described substances will be further described.
The Pb / Ag residue is a zinc leaching residue (a compound of Fe and Zn (zinc) called zinc ferrite), which is a solid content produced by the above-described primary leaching operation, and is further reduced to 2 by SO ₂ or the like. It is the next leaching residue. The main components are PbSO ₄ and SiO ₂ , and in addition, a small amount of Sn · Sb compound and a very small amount of Ag are contained. Each of these components varies depending on the component ratio of the original zinc raw material (zinc concentrate or roasted ore obtained by roasting it). That is, in the original zinc raw material, Pb is small, Pb is small, and if a very small amount of Ag is included, a very small amount of Ag is included. Typical composition ratios of the PbAg residue in our operation are 20% for SiO ₂ , 20% for Pb, other salts such as SO ₄ and Sn · Sb compounds, and Ag is about 2000 ppm. However, the Ag concentration varies depending on the ore blend, and may be 4000 to 5000 ppm.

When the Pb / Ag residue is added to the leaching solution, the SiO _{2 in} the residue is crystalline SiO ₂ because it receives a thermal action during the secondary leaching and does not dissolve in the leaching solution. Pb is also hardly dissolved in sulfuric acid because it exists in the form of PbSO ₄ . As a result, when the zinc raw material was leached with the leachate to which the Pb / Ag residue was added, it is considered that the effect of improving the sedimentation and filterability of the precipitated silica was brought about.
Moreover, since Ag does not dissolve in a non-oxidizing acid, it is considered that the Ag is effective as a seed crystal of silica on which Ag is deposited.

Further, when the Ag is effective as a seed crystal of precipitated silica, from the viewpoint of the absolute abundance of Ag, even in the case of an Ag / Pb residue containing less Ag than in the case of adding Ag in bulk Effective in sedimentation and filterability. This is considered to be caused by the fact that Ag contained in the PbAg residue is finely dispersed and has a large surface area in addition to the above-mentioned cooperative effect of PbSO ₄ and SiO ₂ . Furthermore, although an extremely small amount of Ag is dissolved in the leachate by the oxidizing acid (tetravalent Mn) contained in the leachate, the redox potential of the leachate (below) (Described as ORP.) Decreases, so that once dissolved Ag is precipitated, the coprecipitation effect at that time can also be considered. In addition, the form of Ag is not necessarily a single Ag, and may be a sulfide such as Ag ₂ S or AgCuS. These sulfides also improve the settling and filterability of SiO ₂ as with the simple substance.

Mn starch is a starch supplied from Mn contained in the ore of the zinc raw material. Although there is a difference depending on the type of the ore, the content of Mn contained in the zinc raw material is about 1000 ppm. The Mn is firstly leached by a leachate which is an acidic solution of sulfuric acid and is present in the leachate as divalent Mn ions (Mn ²⁺ ). When electrolytically collecting Zn from the primary leachate, it is common to use a Pb plate as an anode (the use of other materials in the future is also being considered). Mn ²⁺ contained in the above-described leachate is oxidized to Mn ⁴⁺ . At this time, since Mn ⁴⁺ has low solubility, it becomes MnO _{2 and} precipitates and adheres as a scale to the anode. A material obtained by removing and collecting the scale is called Mn starch and the main component is MnO ₂ , but other impurities such as PbO ₂ and SrSO ₄ (strontium sulfate) are contained.

When the Mn starch is added to the leachate, the solid content in the Mn starch is hardly dissolved. For this reason, it acts as a seed crystal when silica is precipitated from the leachate, and is considered to bring about the effect of improving the sedimentation and filterability of the silica. In addition, since MnO ₂ has the effect of increasing the oxidation-reduction potential, adding it to the leaching solution helps leaching Cu contained in the ore of the zinc raw material, and also prevents the precipitation of basic copper sulfate. By being useful, it is thought that the effect of preventing sedimentation deterioration is exhibited.

Hematite is α-Fe ₂ O ₃ produced when the above-described zinc leaching residue is subjected to iron removal treatment. If the hematite was added to the leaching solution, there is a tendency to dissolve but there remains slight solids, the solids as a seed crystal, or act as a co-precipitate during the SiO ₂ deposition, the SiO ₂ It is thought that the effect of improving sedimentation and filterability is brought about.

On the other hand, when Bi ₂ O ₃ is added to the leaching solution, almost the entire amount is dissolved, but when the pH reaches 0.5, the Bi concentration becomes 3000 mg / L and exists as a seed crystal in the leaching solution. Conceivable.
It is considered that Bi ₂ O ₃ existing as a seed crystal acts as a seed crystal when SiO ₂ once dissolved again reprecipitates. Furthermore, since Bi is an extremely heavy element like Pb, the anchor effect due to the high specific gravity of the compound itself is considered to improve the settling and filtering properties of SiO ₂ . Here, the Bi concentration range was adjusted and added to the leachate. As the Bi concentration in the leachate increased, the effect of improving the sedimentation and filterability of silica appeared. However, when the concentration was 4 g / L or more, the effect was significant. Turned out to be.

_{TiO 2, Sb 2 O 3,} SnO 2, Ga 2 O 3, CdO, Ca 3 (PO 4) 2, P 2 O 5, CaF 2, PbO 2, Pd, PbSO 4, PbS, AgO, Ag, Fe 2 When each compound such as O ₃ and MnO ₂ is added to the leachate, it dissolves in the leachate, but these substances are added to the leachate and dissolved to change the liquidity of the leachate and settling / filtration rate This is considered to be improving.

Each of the substances described above is considered to have an effect that it can become a seed crystal of SiO ₂ due to the presence of an oxide on the surface of the substance particles. Furthermore, it is considered that not only the effect of becoming a seed crystal but also the anchor effect due to the high specific gravity of each substance itself improves the sedimentation and filterability of SiO ₂ .

On the other hand, when Pb oxide was added to the leachate, it was found that PbO ₂ is very effective in improving the sedimentation and filterability of SiO ₂ compared to PbS, PbSO ₄ , and PbO. This is considered to be due to the difference in oxide which is the surface property of the particles even if they are the same Pb compound.

In addition, when Ca ₃ (PO ₄ ) ₂ was added to the leachate, the sedimentation property of SiO ₂ was lowered, but the filterability was very good. The cause of this is unknown in detail, but by using the Ca ₃ (PO ₄ ) ₂ in combination with the other seed crystal compounds, the SiO ₂ sedimentation and filterability can be easily achieved. It can be improved. Each of the substances described above is effective even when added alone to the leachate. However, it is also preferable to use a mixture with other substances such as Ca ₃ (PO ₄ ) ₂ described above.

Here, the present inventors are bismuth oxide, titanium oxide, antimony oxide, tin oxide, gallium oxide, cadmium oxide, calcium phosphate, phosphorus oxide, calcium fluoride, lead oxide, lead sulfate, For one or more additive substances selected from lead sulfide, palladium, silver oxide, silver, iron oxide, and manganese oxide, the minimum addition amount that exerts the effect of improving the sedimentation and filterability of the leachate was also examined. As a result, even if the SiO ₂ quality in the target zinc raw material is about 2.3%, it is effective if one or more of each substance is present in the leachate in an amount of 0.02 g / L (about 20 ppm) or more. However, from the viewpoint of workability and the like, it has been found that it is preferable to add 4 g / L or more, more preferably 10 g / L or more. In addition, it is important that each substance to be added is dispersed in the leachate, but it is not necessary to be 100% pure from the viewpoint of purity.

On the other hand, in order to reduce the cost for carrying out the present invention, the present inventors have used Bi dense iron and / or lead electrolytic slime produced in the lead smelting process as a source of bismuth oxide and / or silver. I paid attention to. The lead electrolysis slime is a slime attached to the anode in the electrolytic refining of lead, and its compositional analysis example includes 2 to 20 wt% of lead, 1 to 20 wt% of bismuth, 1 to 20 wt% of antimony, Gold and silver are also included. Here, Bi dense rice cake is obtained by oxidizing this slime and concentrating bismuth in lead oxide. The composition analysis example is 1 to 10 wt% of lead and 50 to 90 wt% of bismuth. is there. Therefore, both Bi dense and lead electrolysis slime contain a large amount of bismuth oxide and silver and are suitable as a source of bismuth oxide and / or silver. Bismuth oxides include BiO, Bi ₂ O ₃ , and mixtures thereof.

  As a result of the study by the present inventors, when Bi bismuth oxide or silver is contained in 3% by weight or more in Bi dense or lead electrolytic slime, it can be used in the same manner as bismuth oxide or silver. In addition, it was found that by adding 4 g / L or more for Bi dense and 1 g / L or more for lead electrolytic slime to the leachate, the effect of improving sedimentation and filterability is exhibited.

Preferably, both Bi dense and lead electrolysis slime are cheaper than Bi ₂ O ₃ and Ag, and the cost of raw materials can be reduced by using these. More preferably, after adding the Bi dense liquid or lead electrolytic slime to the leachate and precipitating and filtering SiO ₂ , the residue obtained through the secondary leaching process can be returned to the lead smelting process again. I can do it. By adopting this configuration, the raw material cost can be greatly reduced.

In addition, the pH of the sulfuric acid acidic solution before leaching containing the substance described above is preferably 1.5 or less. If the pH is 1.5 or less, the acid concentration of the leachate is ensured. Therefore, in terms of diffusion / mass transfer (dC / dt = k · A · (C _L −C _S ) in chemical engineering, The change in concentration per hour is due to the leaching of zinc from the zinc raw material due to the effects of mass transfer coefficient k, extraction area A (including the increase in the number of contacts by stirring), and concentration difference (C _L -C _S ) This is because it becomes easier. As a result, since the leaching time can be shortened, it is possible to avoid complication of processes such as installing many leaching tanks, and the zinc leaching rate is improved.

Furthermore, if the time for leaching the zinc raw material is 10 minutes or longer using the sulfuric acid acid solution before leaching containing the substances described above, the settling / filterability of SiO ₂ can be improved. If it is 5 hours or less, it does not lead to an increase in processing cost, which is a preferable configuration.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these.

電解尾液の液体部分４４０g、脱鉄后液２７２gを混合したものを浸出液とし、ビーカーにセットして温度を60℃に加温した。この時、当該浸出液のｐＨは、おおむね０．０を示し、ORP(Ag/AgCl電極)は、１１５０mVであった。 Example 1
The composition of the roasted zinc raw material used as the raw material is shown in Table 1, and the liquid part of the electrolytic tail solution used as the leaching solution and the composition of the iron free solution are shown in Table 2.

A mixture obtained by mixing 440 g of the liquid portion of the electrolytic tail solution and 272 g of the post-deironation solution was used as a leachate, which was set in a beaker and heated to 60 ° C. At this time, the pH of the leachate was approximately 0.0, and the ORP (Ag / AgCl electrode) was 1150 mV.

Next, PbS, PbSO ₄ , PbO, PbO ₂ , AgO, Ag powder, hematite, Mn starch, Bi ₂ O ₃ , TiO ₂ , Sb ₂ O ₃ , SnO ₂ , Ga ₂ O ₃ , CdO , Pd powder, Ca ₃ (PO ₄ ) ₂ , P ₂ O ₅ and CaF ₂ were prepared.
Here, for AgO and Ag powder, AgO (particle size: about 10 microns), Ag powder (particle size: about 1 micron), and Pb / Ag residue made by Dowa Hightech Co., Ltd. were prepared.
Hematite was prepared by drying and crushing hematite (purity 90% or more) generated in the iron removal process of the zinc smelting process described above.
Mn starch was prepared by collecting starch adhering to the anode in the electrolysis step of the zinc smelting step described above, drying and crushing.
Pb / Ag residue was prepared by drying and crushing what was collected by secondary leaching of the zinc residue in the zinc smelting process described above.
As the Pd powder, Pd powder (particle size: about 100 microns) manufactured by Kosaka Smelting Co., Ltd. was prepared.
As other additives, commercially available reagents were prepared.

6.6 g of each additive material was weighed and each was added to the leachate and stirred for 5 minutes prior to the addition of the sinter. The stirring speed is 300 rpm. The liquid temperature, pH, and ORP of the leachate after stirring were measured, and further filtered through a 0.2 micron filter to analyze the metal elements in the liquid. The results are shown in Table 3.

  Next, 132 g of the roasted zinc raw material was weighed and poured all at once into the leachate to which each additive substance was added. The temperature of the leachate immediately rose to 80 ° C. or higher, and the pH after 5 minutes was changed from 4.0 to 4.2. In order to maintain the pH of the leachate after the addition of the roasted product at 4.2, a slight amount of the leachate was added and adjusted, and stirring was continued for 30 minutes while heating to leach the roasted zinc raw material. During the leaching, the temperature of the leachate was controlled at 80 ° C. At this time, the pH of the leachate was 4.1 to 4.2, and the ORP was 170 to 620 mV.

After completion of the leaching, the temperature, pH, and ORP of the leaching solution were measured, and further filtered with a 0.2 micron filter to analyze the metal elements. The results are shown in Table 4.

Further, in order to evaluate the sedimentation properties of SiO _{2 and the} like from the leachate after completion of leaching, 15 ppm of Sanyo Kasei Co., Ltd. Sanpoly A511 was added as a flocculant to each leachate. Specifically, 1 g of Sunpoly was diluted in 1 L of pure water, and the diluted solution was measured and added with a syringe having an internal volume of 9 ml. After adding the flocculant, the mixture was further stirred manually for 10 seconds, and then the leachate was transferred to a 1 L graduated cylinder to evaluate the sedimentation property for 30 minutes. The evaluation was made visually and with a stopwatch. A list of the sedimentation evaluation results is shown in Table 5. In addition, the sedimentation evaluation results for each time are shown in FIG. 2 as a graph with the sedimentation distance on the vertical axis and the time on the horizontal axis. The evaluation results are shown in FIG. 3 as a bar graph, and similarly, the sedimentation evaluation results after 30 minutes are shown in FIG.

  Here, from the sedimentation evaluation result after 1 minute, it is possible to evaluate the speed of sedimentation speed of the solid content in the solid-liquid separation step after the primary leaching. Moreover, the slurry density in a post process can be evaluated from the sedimentation evaluation result after 30 minutes. That is, the underflow slurry in the subsequent process is subjected to solid-liquid separation by a filter press or the like, and the obtained solid content is processed in the secondary leaching process. At this time, if the sedimentation evaluation result after 30 minutes is small, there is a correlation that the slurry density is low and the cake density of the slurry applied to the filter press and the like is also low. When the cake density is low, there is a problem that the plate opening work such as a filter press increases and the productivity is lowered. Moreover, if the sedimentation evaluation result after 30 minutes is small, the filtration rate tends to be slow, which also causes the problem of reduced productivity.

After the 30-minute evaluation, the slurry settled in the graduated cylinder was placed in a pressure filter equipped with a 116 mm diameter, 3 micron PTFE filter paper and pressure filtered at 4 kgf / cm ² to allow time for total discharge. Measurement was performed to measure the filtration rate, and the filterability of each slurry was evaluated. A list of the filterability evaluation results is shown in Table 5, and the filtration rate for each additive substance is shown in a bar graph in FIG. At this time, the leachate was slightly cooled, and the temperature of the solution was 60 ° C to 45 ° C.

(Comparative Example 1)
The raw materials and the leachate used were the same as in Example 1, but the same operation as in Example 1 was performed without adding any additional substances to the leachate.
First, the temperature of the leachate to which each additive substance was not added was set to 60 ° C., pH and ORP were measured, and further filtered through a 0.2 micron filter to analyze metal elements. The results are also shown in Table 3.

  Next, 132 g of the roasted zinc raw material was weighed and poured all at once into the leachate. The temperature of the leachate immediately increased to about 80 ° C., and the pH after 5 minutes was 4.1. The results are also shown in Table 4. In order to maintain the pH of the leachate after the addition of the roasted product at 4.2, a slight amount of the leachate was added and adjusted, and stirring was continued for 30 minutes while heating to leach the roasted zinc raw material. The temperature was controlled at 80 ° C. during the leaching.

After completion of the leaching, the temperature, pH, and ORP of the leaching solution were measured, and further filtered with a 0.2 micron filter to analyze the metal elements. The results are shown in Table 4.
In the same manner as in Example 1, 15 ppm of a flocculant was added to the leachate, and the mixture was further stirred by hand for 10 seconds, and then the settling property for 30 minutes was evaluated. A list of the sedimentation evaluation results is also shown in Table 5. In addition, the sedimentation evaluation results are shown in FIG. 4 as a graph with the vertical axis representing the sedimentation distance and the horizontal axis representing time. Is shown by a bar graph in FIG. 2, and similarly, the sedimentation evaluation results after 30 minutes are shown in FIG.
Further, the filterability of the slurry was evaluated in the same manner as in Example 1. The list of the filterability evaluation results is also shown in Table 5, and the filtration rate is shown in a bar graph in FIG. At this time, the leachate was slightly cooled and the liquid temperature was 60 ° C.

(Summary of Example 1 and Comparative Example 1)
From the test results shown in Tables 3 to 5, Example 1 in which each substance to be a seed crystal was added was compared with Comparative Example 1 in which each substance was not added. Then, from Table 3, even when any substance was added, at least one of sedimentation or filterability was improved as compared with the case where no substance was added. Then, added PbO _2, AgO, Ag powder, hematite, Mn grout _{material, Bi 2 O 3, TiO 2} , Sb 2 O 3, SnO 2, Ga 2 O 3, CdO, Pd, and P ₂ O _5, CaF ₂ In this case, the sedimentation and filterability were improved as compared with the case of no addition. Furthermore, it was found that when PbO ₂ , Ag powder, Bi ₂ O ₃ , Ca ₃ (PO ₄ ) ₂ , and CaF ₂ were added, the filterability was improved more than when PbAg residue was added.

Moreover, the following thing was considered from the result of Table 4.
Even if PbO ₂ is added to the leachate, the Pb concentration does not increase so much, but the Mn concentration decreases. At this time, it is observed that Mn is precipitated as MnO ₂ . That is, it is estimated that most of PbO ₂ is a seed crystal.
With the addition of AgO, almost the entire amount was dissolved and remained dissolved even after leaching. Nevertheless, the improvement in sedimentation compared to Comparative Example 1 is believed to be due to a change in liquidity.
When Ag powder was added, about half was dissolved, but it was deposited with an increase in pH, so it did not remain in the liquid. In other words, it is possible that Ag has developed both the effect of coprecipitation and the effect as a seed crystal.
When hematite is added, the Fe concentration is slightly increased, so it is considered that it has partially dissolved, but most of it is considered that the effect was exhibited by remaining as a seed crystal.
With Bi ₂ O ₃ addition, almost the entire amount is dissolved before leaching. And since Bi does not exist in the liquid after leaching, it is possible that both the effect of coprecipitation and the effect as a seed crystal have been developed.
When Sb ₂ O _{3 was} added, partly dissolved and partly undissolved, so it is possible that both the effect of coprecipitation and the effect as a seed crystal were expressed.
The addition of SnO ₂ and Ga ₂ O ₃ is considered to be effective as a seed crystal because it is almost undissolved.
When CdO was added, the entire amount was dissolved and remained dissolved even when the pH increased. Nevertheless, the improvement in sedimentation compared to Comparative Example 1 is believed to be due to a change in liquidity.
With the addition of Ca ₃ (PO ₄ ) ₂ and CaF ₂ , the Ca concentration in the leachate before the addition of the roasted zinc raw material was slightly increased. It is thought that the effect was demonstrated as a seed crystal.
The P ₂ O ₅ addition, the reaction of _{P 2 O 5 + 3H 2 O} → 2H 3 PO 4, are dissolved at the same time taking into H ₃ PO ₄ next leachate.

(Example 2)
As raw materials, a roasted zinc raw material similar to that described in Example 1, a liquid portion of an electrolytic tail solution and a post-iron removal solution were prepared as a leachate. In the same manner as in Example 1, a mixture of 440 g of the liquid portion of the electrolytic tail solution and 272 g of the post-deironation solution was used as the leachate.

Commercially available Bi ₂ O ₃ was prepared, added to the leachate and stirred for 5 minutes, and the Bi ₂ O ₃ concentration was 0 g / L (0 wt%), 1 g / L (0.5 wt%), 2 g / L. (1 wt%), 4 g / L (2 wt%), and 8 g / L (4 wt%) samples were prepared. The stirring speed is 300 rpm.

  Next, weighed 132 g of the zinc raw material and put it into each sample solution at once, followed by the same treatment as in Example 1. After leaching was completed, pH and ORP were measured, and a 0.2 micron filter was added. The metal element was analyzed by filtration. The results are shown in Table 6.

Further, in the same manner as in Example 1, the sedimentation properties of SiO _{2 and the} like from the leachate after completion of leaching were evaluated. The sedimentation evaluation result is shown in FIG. 6 using a graph in which the vertical axis represents the sedimentation distance and the horizontal axis represents time, with the sedimentation evaluation result for each hour. Furthermore, the filtration rate is shown in FIG. In FIG. 7, the vertical axis represents the filtration rate, and the horizontal axis represents the amount of Bi ₂ O ₃ added.

From the results shown in FIGS. 6 and 7, it was found that both the sedimentation distance and the filtration rate were improved by adding Bi ₂ O _{3 to} the leachate. Then, the effect of addition, the addition amount of Bi ₂ O ₃ becomes remarkable when a 4g / L (2wt%) or more.

(Example 3)
A leachate was prepared in the same manner as in Examples 1 and 2. In addition to Bi ₂ O ₃ described in Example 2, commercially available Ag, Bi dense iron taken from the lead smelting process, and Pb electrolytic slime were prepared. Each sample was prepared by adding 10 g / L (5 wt%) of these to the leachate. The stirring speed is 300 rpm.
Table 7 shows the analysis results of the Bi dense and Pb electrolytic slime. From Table 8, it was found that both the Bi dense shell and the Pb electrolytic slime contained 3 wt% or more of Bi and Ag.

  Next, in the same manner as in Example 12, the zinc raw material was weighed and poured into each sample solution at once, and then the same treatment as in Examples 1 and 2 was performed. After leaching was completed, pH and ORP were measured. Further, the metal element was analyzed by filtering through a 0.2 micron filter. The results are shown in Table 8.

In addition, as in Examples 1 and ₂ , the sedimentation properties of SiO _{2 and the} like from the leachate after completion of leaching were evaluated. FIG. 8 shows a graph using the sedimentation evaluation result as the sedimentation evaluation result for each hour, with the vertical axis representing the sedimentation distance and the horizontal axis representing the time. Further, the filtration rate of each sample is shown in FIG. 9, the sedimentation test result (after 2 minutes) is shown in FIG. 10, and the sedimentation test result (after 30 minutes) is shown in FIG.

From the results of FIGS. 8 to 11, it was found that the sedimentation distance and the filtration rate were remarkably improved by the addition of Bi dense cake and Pb electrolytic slime to the leachate. This addition effect was also found to be superior to that of the same amount of Bi ₂ O ₃ and silver.

It is an example of the processing flow of the zinc raw material which concerns on embodiment of this invention. It is a graph which shows the sedimentation evaluation result for every time when each additive substance which concerns on Example 1 of this invention and a comparative example is added. It is the bar graph which showed the sedimentation evaluation result after 1 minute when each additive substance which concerns on Example 1 of this invention and a comparative example was added. It is the bar graph which showed the sedimentation evaluation result after 30 minutes when each additive substance which concerns on Example 1 of this invention and a comparative example was added. It is a bar graph which shows the filterability evaluation result when each additive substance which concerns on Example 1 and a comparative example of this invention is added. Is a graph showing the sedimentation property evaluation results of each time upon addition of Bi ₂ O ₃ according to the second embodiment of the present invention. It is a graph showing the filtration rate when adding a Bi ₂ O ₃ according to the second embodiment of the present invention. It is a graph which shows the sedimentation evaluation result for every time when each additive substance which concerns on Example 3 of this invention is added. It is a bar graph which shows the filtration rate when each additive substance which concerns on Example 3 of this invention is added. It is the bar graph which showed the sedimentation evaluation result after 2 minutes when each additive substance which concerns on Example 3 of this invention was added. It is the bar graph which showed the sedimentation evaluation result after 30 minutes when each additive substance which concerns on Example 3 of this invention was added.

Claims (10)

In the wet zinc smelting process to extract zinc from zinc raw materials,
When leaching the roasted zinc raw material using sulfuric acid acidic solution, bismuth oxide, titanium oxide, antimony oxide, tin oxide, gallium oxide, cadmium oxide, calcium phosphate salt, phosphorus oxide, calcium fluoride, Leaching using an acidic sulfuric acid solution with at least one additive selected from lead oxide, lead sulfate, lead sulfide, palladium, silver oxide, silver, iron oxide, and manganese oxide A method for processing a zinc raw material. The method for treating a zinc raw material according to claim 1, wherein hematite produced from the wet zinc smelting step is used as the iron oxide . The method for treating a zinc raw material according to claim 1, wherein Mn starch produced from the wet zinc smelting step is used as the manganese oxide . As the bismuth oxide and / or silver ,
The zinc raw material treatment method according to claim 1 or 2, wherein Bi dense iron and / or lead electrolytic slime produced from a lead smelting step and containing 3 wt% or more of Bi or Ag is used.   5. The method for treating a zinc raw material according to claim 1, wherein one or more of the additive substances are added and a sulfuric acid acidic solution containing 0.02 g / L or more of the additive substance is used. _{2. The} method for treating a zinc raw material according to claim 1, wherein Bi ₂ O ₃ is used as the additive substance and 4 g / L or more is added to the sulfuric acid acidic solution.   2. The zinc raw material treatment method according to claim 1, wherein Bi additive from the lead smelting process is used as the additive substance, and 4 g / L or more is added to the sulfuric acid acidic solution.   2. The method for treating a zinc raw material according to claim 1, wherein 1 g / L or more is added to the sulfuric acid acidic solution using lead electrolytic slime produced from a lead smelting step as the additive substance.   The zinc raw material treatment method according to any one of claims 1 to 8, wherein a pH of the sulfuric acid acidic solution before the leaching is set to 1.5 or less.   The method for treating a zinc raw material according to any one of claims 1 to 9, wherein a time for leaching the zinc raw material is 10 minutes to 5 hours.

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