JP2005126747A - Method for recovering valuables - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently recovering noble metals from material containing at least the noble metals, e.g. gold, silver, platinum group, etc., originating from a copper electrolytic slime, and selenium and tellurium, and a method for efficiently recovering the selenium and the tellurium from the above material. <P>SOLUTION: The method for recovering a valuables is characterized in that the material containing the noble metals, the selenium and the tellurium and an inorganic compound having a melting point and a decomposition point of ≥800°C each and a solubility of ≥10 g/100mL to water at 20°C are mixed and the obtained mixture are heated to 500-800°C under the oxygen-containing atmosphere to sublime the selenium and the tellurium, and the obtained residue is mixed with water base solvent and the noble metal is recovered by filtrating the obtained mixture. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a valuable material recovery method. More specifically, for example, the present invention relates to a method for recovering valuable materials recovered from materials such as copper electrolytic slime containing valuable materials such as noble metals such as gold, silver and platinum groups, selenium and tellurium. In addition, the valuable material as used in this specification means the said noble metal, selenium, and tellurium.

As a method of separating selenium and tellurium by roasting a material containing at least selenium and tellurium, such as gold, silver and platinum groups derived from copper electrolytic slime, in an oxidizing atmosphere,
(A) A method of adding one or more nitrates that decompose in a temperature range of 150 to 700 ° C. and baking in a non-reducing atmosphere (see, for example, Patent Document 1),
(B) A crushed material of a scrap alloy containing selenium and tellurium and a granular medium (specifically, for example, river sand) excellent in acid resistance, alkali resistance, and heat resistance in an oxidizing atmosphere, and a roasting temperature of 400 to 800 The scrap alloy is oxidized at a temperature of 0 ° C., and selenium dioxide or arsenous acid is sublimated to collect selenium dioxide. A method of recovering valuable materials from a scrap alloy characterized by carrying out and separating selenium and tellurium (see, for example, Patent Document 2)
Etc. are known.

  However, the method (A) is intended to recover selenium smoothly by reducing selenium dioxide gas generated mainly by roasting with sulfur dioxide gas generated in large amounts at the same time. There is no mention of how to recover precious metals such as the platinum group.

In addition, the method (B) is excellent as a method for recovering selenium and tellurium. However, when gold, silver and platinum group noble metals are obtained as concentrates, a large amount of sand is mixed in the concentrate. , There is a drawback that a complicated operation is required for the removal.
Japanese Patent Publication No.51-23452 Japanese Examined Patent Publication No. 4-63003

  The present invention has been made in view of the prior art, for example, efficiently recovering a noble metal from a material containing at least selenium and tellurium such as gold, silver, platinum group and the like derived from copper electrolytic slime. It is an object to provide a method. Another object of the present invention is to provide a method capable of efficiently recovering selenium and tellurium from the material.

The present invention
(1) A material containing a noble metal, selenium and tellurium was mixed with an inorganic compound having a melting point and a decomposition point of 800 ° C. or higher and a solubility in water at 20 ° C. of 10 g / 100 mL or higher. By sublimating selenium and tellurium by heating the mixture to a temperature of 500-800 ° C. in an oxygen-containing atmosphere, mixing the resulting residue with an aqueous solvent, and filtering off solids from the resulting mixture. A method for recovering valuable materials, characterized by recovering precious metals;
(2) The method for recovering a valuable material according to the above (1), wherein the recovered selenium and tellurium are recovered by absorbing them in an aqueous solvent, and
(3) It relates to valuables recovered by the recovery method.

  According to the valuable material recovery method of the present invention, for example, noble metals such as gold, silver and platinum groups, copper electrolytic slime containing selenium and tellurium, and the like, noble metals, selenium and tellurium are industrially efficient. It can be recovered well.

  In addition, according to the present invention, since the operation of mixing the residue obtained by heating the mixture of the material and the inorganic compound with an aqueous solvent is taken, the inorganic compound can be removed very easily. As a result, it is possible to recover the precious metal efficiently. This effect is an effect peculiar to the present invention which is not manifested in the invention described in Japanese Examined Patent Publication No. 4-63003 (Kawasuna method).

  In the valuable material recovery method of the present invention, a material containing noble metal, selenium and tellurium is used as the object. Specific examples of such materials include copper electrolytic slime containing noble metals, selenium and tellurium.

  Examples of the noble metal include gold, silver, and platinum group, but the present invention is not limited to such examples.

  The content of noble metals, selenium and tellurium in the material, and the composition thereof are not particularly limited. As said material, the material of the composition described in Table 1 is mentioned, for example. In addition to the noble metal, selenium and tellurium, the material may contain arsenic, copper, iron, sulfur and the like within a range that does not impair the object of the present invention.

  In the valuable material recovery method of the present invention, first, the material is mixed with an inorganic compound having both a melting point and a decomposition point of 800 ° C. or higher and a solubility in water at 20 ° C. of 10 g / 100 mL or higher.

  In the present invention, since an inorganic compound having both a melting point and a decomposition point of 800 ° C. or higher is used in this way, by sublimating selenium and tellurium when the mixture of the material and the inorganic compound is heated. Selenium and tellurium can be efficiently removed from the material.

  In the present invention, since the solubility of the inorganic compound in water at 20 ° C. is 10 g / 100 mL or more, when the resulting residue is mixed with an aqueous solvent, the inorganic compound contained in the residue is efficiently removed. Since it can be dissolved, the noble metal contained in the residue can be efficiently recovered.

  Typical examples of the inorganic compound include alkali metal sulfates such as sodium sulfate and potassium sulfate, alkaline earth metal sulfates such as magnesium sulfate, and alkali metal chlorides such as sodium chloride and potassium chloride. Among these, sodium sulfate and / or potassium sulfate are preferable from the viewpoints of solubility, operability, and the like.

The mixing ratio of the material and the inorganic compound is preferably 50 to 1000 parts by weight, more preferably 80 parts by weight per 100 parts by weight of the material from the viewpoint of roasting efficiency, economy, operability (handling) and the like. It is desirable to adjust so that it may become -500 weight part, More preferably, it will be 100-200 weight part.
In addition, it is preferable to perform mixing of the said material and an inorganic compound until both disperse | distribute uniformly.

  In the present invention, since the operation of mixing the material and the inorganic compound is employed, when the resulting mixture is heated to a predetermined temperature, the material contained in the mixture is a shell-like solid. Heating can be prevented from becoming a product, and the residue obtained by heating becomes a granular material exhibiting fluidity, so that the handling thereof is facilitated.

  Next, the obtained mixture is heated to a temperature of 500 to 800 ° C. in an oxygen-containing atmosphere. In the present invention, since the oxygen-containing atmosphere is used in this way, selenium and tellurium contained in the mixture can be sublimated mainly in the form of an oxide during heating and efficiently removed from the mixture.

  Examples of the oxygen-containing atmosphere include air, oxygen, and a mixed gas of oxygen and another gas such as an inert gas. However, the present invention is not limited to such examples. Among these, air is preferable from the viewpoint of economy.

  The temperature at which the mixture is heated is adjusted to 500 to 800 ° C., preferably 600 to 780 ° C., from the viewpoint of efficiently sublimating selenium and tellurium and increasing the fluidity of the mixture in the furnace. Is done.

  When the mixture is heated, a roasting furnace can be used. Examples of the roasting furnace include a rotary kiln, a fluidized bed furnace, a conveyor transfer furnace, a rotary table furnace, and the like, but the present invention is not limited to such examples. As the roasting furnace, selenium and tellurium can be efficiently sublimated and the residue can be easily taken out from the furnace, so that the type of roasting furnace heated from the outside of the furnace, for example, an external heating type A rotary kiln is preferred.

  Thus, by heating the mixture to a predetermined temperature in an oxygen-containing atmosphere, selenium and tellurium can be sublimated mainly in the form of oxides from the mixture.

  In addition, after heating, the inorganic compound contained in the mixture is contained in the residue together with the noble metal. Therefore, this residue can be used in place of the inorganic compound. Such an operation can be repeated, for example, several times to 10 times. In addition, what is necessary is just to determine suitably the frequency | count of repeating the said operation according to the quality and composition of a residue.

  Selenium and tellurium are sublimated from the mixture, and the resulting residue is then mixed with an aqueous solvent.

  Examples of the aqueous solvent include water and acidic aqueous solvents. Among the aqueous solvents, acidic aqueous solvents are preferable from the viewpoint of efficiently removing inorganic compounds and impurities contained in the residue. Examples of the acidic aqueous solvent include hydrochloric acid and a sulfuric acid aqueous solution. In addition, when hydrochloric acid is used as the aqueous solvent, the concentration of hydrogen chloride is not particularly limited, but it is usually preferably about 5 to 20% by weight. Further, when an aqueous sulfuric acid solution is used as the aqueous solvent, the concentration is not particularly limited, but it is usually preferably about 5 to 30% by weight.

  The amount of the aqueous solvent may be an amount that sufficiently dissolves the inorganic compound contained in the residue. The amount of the aqueous solvent is usually preferably 300 to 10,000 parts by weight, more preferably 500 to 5000 parts by weight per 100 parts by weight of the residue.

  Next, the inorganic compound contained in the residue is removed as an aqueous solution by filtering the solid containing the noble metal from the mixture of the residue and the aqueous solvent, and the noble metal contained in the residue is recovered as a solid. can do. Since the collected solid matter contains a noble metal at a high concentration, the noble metal contained in the solid matter can be used effectively.

  On the other hand, selenium and tellurium contained in the material are sublimated mainly in the form of oxides when the mixture of the material and the inorganic material is heated. Sublimated selenium and tellurium can be recovered, for example, as a selenious acid aqueous solution by cooling to a temperature of 100 ° C. or lower and absorbing it in an aqueous solvent. Further, tellurium can be effectively used by recovering tellurium as a precipitate of tellurate by neutralizing an aqueous solvent in which an aqueous solvent having absorbed selenium and tellurium is added.

  As described above, the valuable material recovery method of the present invention can recover not only precious metals but also sublimated selenium and tellurium, and thus can effectively use earth resources.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to such examples.

Example 1
As a material containing selenium and tellurium, copper electrolytic slime (main components: selenium 84.3% by weight, tellurium 2.8% by weight, lead 2.82% by weight, gold 0.73% by weight, palladium 0.059% by weight After crushing this, the obtained crushed material and anhydrous sodium sulfate as an inorganic compound were mixed at a weight ratio of 1: 1, and the resulting mixture was mixed with an externally heated rotary kiln type roasting furnace [Osaka Furnace To Kogyo Co., Ltd.] at a rate of 10 kg / hour.
The atmosphere in the furnace was air, and the heating temperature was adjusted to 750 ° C. and heated for about 2 hours.

  After heating, the residue in the furnace was taken out. This residue contained precious metals originally contained in copper electrolytic slime. Therefore, in order to effectively use the precious metal contained in the residue, the residue and the crushed copper electrolytic slime having the same composition as described above are mixed with the same weight, and then heated in the same manner as described above. It was. When this operation was repeated a total of 6 times, a total of 60 kg of copper electrolytic slime could be treated, resulting in a residue of 14.7 kg. Table 2 shows the result of analyzing the composition of the obtained residue.

  Next, 14.7 kg of the obtained residue was put into 250 L of water, stirred at 40 ° C. for 1 hour, and solids were collected by filtration from the obtained mixture, recovered, washed with water, and then dried. Was 4.5 kg. The composition of the collected solid is also shown in Table 2.

  In addition, all the gas discharged | emitted from the furnace was collect | recovered, and after making it cool to the temperature of 100 degrees C or less, it was made to absorb in water. As a result, the water contained 67.4 kg of selenium dioxide and 1.8 kg of tellurium dioxide. From this, it can be seen that selenium and tellurium sublimated and discharged from the furnace by the heating can be efficiently captured in water.

Example 2
In the same manner as in Example 1, crushed copper electrolytic slime and anhydrous sodium sulfate as an inorganic compound were mixed at a weight ratio of 1: 1, and the resulting mixture was heated, and then 14.7 kg of residue from the furnace. Was taken out.

  14.7 kg of this residue was put into a mixed solution of 83 L of 35% hydrochloric acid and 167 L of water, and stirred at 60 ° C. for 3 hours. A solid matter was collected by filtration from the obtained mixture, washed with water, and dried. However, the weight was 2.65 kg. The composition of the collected solid is also shown in Table 2.

Comparative Example 1
In Example 1, instead of anhydrous sodium sulfate, silica sand was used in the same manner as in the invention described in Japanese Patent Publication No. 4-63003, and the crushed copper electrolysis slime and silica sand were mixed at a weight ratio of 1: 1. When others were heated in the same manner as in Example 1, a total of 60 kg of copper electrolytic slime could be processed, and as a result, 14.8 kg of residue was obtained. Table 2 shows the result of analyzing the composition of the obtained residue.

From the results shown in Table 2, in contrast to Comparative Example 1 in which silica sand was used, in each Example in which an inorganic compound was used, by treatment with water (Example 1) or hydrochloric acid (Example 2). It can be seen that since the inorganic compound contained in the residue can be efficiently removed, the content of noble metals such as gold, silver, and platinum group in the obtained solid can be remarkably increased. In particular, as in Example 2, when the residue is mixed with an acidic aqueous solvent (hydrochloric acid), it can be seen that the content of the noble metal in the solid recovered by filtration can be further increased.
That is, when the noble metal is recovered from the solid from which the tellurium, anhydrous sodium sulfate, etc. have been removed, the solid contains 15% by weight of gold, and when other noble metals are included, the content of the noble metal is about 35%. % By weight. From this, according to this Example 2, it turns out that the solid substance which contains a noble metal in high concentration can be efficiently collect | recovered.

Example 3
In Example 1, except that the heating temperature was changed from 750 ° C. to 550 ° C. and the processing operation was changed from 6 times to 4 times, the same operation as in Example 1 was performed. The electrolytic slime could be processed, resulting in a residue of 13.6 kg. Table 3 shows the result of analyzing the composition of the obtained residue.

  On the other hand, all the gas discharged from the furnace was recovered, cooled to 100 ° C. or lower, and then absorbed in an aqueous solvent to recover selenium as an aqueous selenious acid solution. Moreover, when the pH of this aqueous solution was adjusted to 4.0 with an aqueous sodium hydroxide solution, tellurium could be precipitated as tellurate, and this was recovered by filtration.

  Next, the pH of the obtained filtrate was adjusted to 2 with hydrochloric acid, and sodium bisulfite was added to precipitate selenium, which was recovered. As a result, the recovered selenium had a high purity of 99.9%, and the recovery rate was as high as 95%.

  Moreover, the separation rate of selenium determined by dividing the weight of selenium in the obtained residue by the weight of selenium contained in the copper electrolytic slime used as a raw material is 99% by weight, and is recovered. The tellurium separation rate determined by dividing the weight of tellurium by the weight of tellurium contained in the copper electrolytic slime used as a raw material was 15%. From this, it can be seen that according to Example 3, selenium can be efficiently recovered.

Example 4
13.6 kg of the residue obtained in Example 3 was put into a mixed solution of 83 L of 35% hydrochloric acid and 167 L of water, stirred at 60 ° C. for 3 hours, and solids were collected by filtration from the obtained mixture, and washed with water. And then dried, the weight was 4.47 kg. Table 3 shows the composition of the collected solid.

  From the results shown in Table 3, it can be seen that according to Example 3, selenium can be efficiently recovered with a high separation rate. According to Example 4, since the inorganic compound and the like contained in the residue can be efficiently removed by treatment with hydrochloric acid, the content of noble metals such as gold, silver, and platinum group in the obtained solid matter It can be seen that can be significantly increased.

Example 5
After adding 10 parts by weight of the residue obtained in Example 3 to 60 parts by weight of 10% hydrochloric acid, heating to 40 ° C. and stirring for 5 hours, solids were collected by filtration from the resulting mixture and washed with water. When dried, 92% by weight of tellurium contained in the residue and most of anhydrous sodium sulfate could be removed.

  When the noble metal was recovered from the solid from which the tellurium, anhydrous sodium sulfate, etc. had been removed, the solid contained 6.46% by weight of gold, and when other noble metals were included, the noble metal content was about 14%. 3% by weight. From this, according to this Example 5, it turns out that the solid substance which contains a noble metal in high concentration can be efficiently collect | recovered.

  Next, 300 L of the obtained filtrate and 139 g of the telluric acid precipitate obtained in Example 3 were mixed, adjusted to pH 2 with hydrochloric acid, and heated to 80 ° C. to thereby obtain telluric acid salt. After dissolution, 556.5 g (2.2 mol) of 35 wt% sodium bisulfite was added dropwise, tellurium precipitated, filtered and dried to obtain 978 g of tellurium. That is, tellurium could be recovered at a high recovery rate of 90% by weight from the copper electrolytic slime used as a raw material.

  The valuable material recovery method of the present invention is capable of efficiently recovering valuable materials such as gold, silver, platinum group and other precious metals derived from materials such as copper electrolytic slime, selenium, tellurium, etc. Valuables can be used effectively as valuable earth resources.

Claims (7)

  A material containing a noble metal, selenium and tellurium is mixed with an inorganic compound having a melting point and a decomposition point of 800 ° C. or more and a water solubility at 20 ° C. of 10 g / 100 mL or more, and the resulting mixture is mixed with oxygen. Selenium and tellurium are sublimated by heating to a temperature of 500 to 800 ° C. in a contained atmosphere, the resulting residue is mixed with an aqueous solvent, and the resulting mixture is filtered to recover the noble metal. Characteristic valuable material recovery method.   The method for recovering valuable materials according to claim 1, wherein the sublimated selenium and tellurium are recovered by absorbing them in an aqueous solvent.   The recovery method according to claim 1 or 2, wherein the inorganic compound is an alkali metal sulfate.   The recovery method according to claim 3, wherein the alkali metal sulfate is sodium sulfate and / or potassium sulfate.   The recovery method according to claim 1, wherein the aqueous solvent is an acidic aqueous solvent.   6. The recovery method according to claim 5, wherein the acidic aqueous solvent is hydrochloric acid or a sulfuric acid aqueous solution.   Valuables recovered by the recovery method according to claim 1.