KR100888040B1 - Method of recovering platinum metals from waste catalysts - Google Patents

Abstract

A method of recovering platinum metals from spent catalysts is provided to recycle obtained alum or aluminium hydroxide as alumina material by changing refractory alumina into availability alum or aluminium hydroxide. Spent catalyst is mixed with one or more strong bases to 1:1~1:3 based on equivalence ratio and roasts in 400~900°C for ~4 hours. After the roasted material is dissolved in the water, the insolubility platinum based metal separates solid-liquid. The strong base is selected in the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide.

Description

METHOD OF RECOVERING PLATINUM METALS FROM WASTE CATALYSTS}

The present invention relates to a method for recovering a platinum group metal from a spent catalyst containing a platinum group metal, and more particularly, to a method for recovering a platinum group metal with high recovery rate by converting the carrier component of the spent catalyst into soluble to dissolve and separate it in water. It is about.

Platinum group metals such as Platinum (Pt) and Palladium (Pd) have high melting points, high specific gravity, and are not used to erode acids and alkalis. In particular, this platinum group metal is used as a catalyst in liquefied petroleum gas (LPG) production, acetylene and methyl acetylene hydrogenation processes, reforming processes, etc. in petrochemical and refinery plants.

When platinum group metals are used as catalysts, they are supported on a carrier such as aluminum and used up after about 3-4 years. They are discarded because they are expensive and almost depend on imports. have.

In general, there are two techniques for recovering the platinum group metal from the noble metal waste catalyst: dry method and wet method.

The dry method is a method in which a waste catalyst is heated to a high temperature to melt a platinum group element and recover it from a carrier, which is suitable for large-volume processing. This method has the disadvantage that the initial investment is high, slag is generated, and air pollutants are generated to intensify air pollution.

The wet method is suitable for small-volume treatment, but this method does not generate slag, but a large amount of waste acid is generated by using a large amount of strong acid, and there is a limitation in the installation.

Common wet methods include direct leaching of platinum group metals by aqua regia or hydrochloric acid, and concentration of recovered insoluble platinum group metals by dissolving alumina of the spent catalyst with sulfuric acid. In this method, the carrier must be finely ground and the finely ground carrier lowers the energy efficiency in the solid-liquid separation process after leaching. In addition, the platinum group metal leach solution is absorbed by the porous alumina residue remaining as a residue after leaching, so that some platinum group metals are lost.

In addition, there is also a method of recovering the platinum group metal by dissolving the spent catalyst in ammonium sulfate, but in this case, a large amount of ammonium sulfate is required and the waste catalyst dissolution rate is low and a large amount of air pollutants are generated.

Therefore, the inventors of the present invention devised a careful study, as a result of developing a method for increasing the recovery rate of platinum group metal by increasing the dissolution rate of the waste catalyst in water by roasting the waste catalyst at a high temperature with a strong acid or strong base. Reached.

An object of the present invention is to provide a method for converting a carrier of a spent catalyst to water solubility to recover the platinum group metal contained therein with high recovery rate.

Another object of the present invention is to convert the alumina carrier spent catalyst into water soluble so that aluminum can be reused.

It is another object of the present invention to reduce the amount of waste catalyst disposed of to prevent environmental pollution.

The method for recovering the platinum group metal from the spent catalyst of the present invention,

In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal,

The waste catalyst is roasted at 400 to 900 ° C. with a strong acid or strong base, and the roasted product is dissolved in water and then solid-liquid separated.

In addition, the method for recovering the platinum group metal from the spent catalyst of the present invention,

In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal,

Firstly roasting the spent catalyst at 400 to 900 ° C. with a strong acid or strong base;

Dissolving the first roasted product in water and separating the first solid solution;

Mixing the strong base to the solid-liquid separated filtrate and then roasting at 400 to 900 ° C. for two times; And

And dissolving the secondary roasted product in water and separating the second solid solution.

By using the method for recovering the platinum group metal from the spent catalyst of the present invention, the platinum group metal can be recovered with high recovery rate by converting the carrier component of the spent catalyst into soluble and dissolving it in water.

In particular, when an alumina carrier spent catalyst is used, the alum and / or aluminum hydroxide obtained by converting poorly soluble alumina into soluble alum and / or aluminum hydroxide can be recycled as an alumina raw material.

In addition, the high concentration of the platinum group metal, it is possible to treat a large amount of waste catalyst by using a wet equipment that was difficult to process a large capacity waste catalyst.

In addition, it is possible to prevent the environmental pollution by reducing the amount of waste catalyst disposed of.

The method for recovering the platinum group metal from the spent catalyst of the present invention,

In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal,

The waste catalyst is roasted at 400 to 900 ° C. with a strong acid or strong base, and the roasted product is dissolved in water and then solid-liquid separated.

Next, the method for recovering the platinum group metal from the spent catalyst of the present invention will be described in more detail.

The waste catalyst preferably used in the present invention is an alumina carrier waste catalyst. Therefore, hereinafter, alumina carrier waste catalyst will be described as an example of waste catalyst. However, in the present invention, the waste catalyst containing the platinum group metal is not limited to the alumina carrier waste catalyst.

First, the alumina carrier spent catalyst and strong acid or strong base are roasted at 400 to 900 ° C. At this time, the waste catalyst can be used with or without pulverization. If the roasting temperature is less than 400 ℃ does not sufficiently change the carrier component solubility in water is low, if the roasting temperature exceeds 900 ℃ there is a problem that is not economical without improving the effect by roasting. More preferable roasting temperature is 400 to 700 ° C.

In addition, roasting is preferably performed for 1 to 4 hours. If the roasting time is less than 1 hour, the change in the alumina carrier component is not sufficiently made solubility in water is low, if the roasting time is more than 4 hours there is a problem that is not economical without increasing the solubility in water.

In the method for recovering the platinum group metal from the spent catalyst of the present invention, when a strong acid is used as the flux, the strong acid is selected from the group consisting of hydrochloric acid, sulfuric acid and nitric acid.

In addition, when a strong base is used as the flux, the strong base is characterized in that at least one selected from the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide.

In the method for recovering the platinum group metal from the waste catalyst of the present invention, the mixing ratio of the waste catalyst and the strong acid or the strong base is 1: 1 to 1: 3 based on the equivalent ratio. When the mixing ratio of the spent catalyst and strong acid or strong base is 1: 1 or less, the carrier component is not sufficiently changed, so the roasting efficiency is low. When the mixing ratio of the spent catalyst and strong acid or strong base exceeds 1: 3, the amount of waste acid or waste base is generated. There is a problem.

Preferred mixing ratio of the spent catalyst and strong acid or strong base is 1: 1.2 to 1: 1.5 based on the equivalent ratio. The reaction efficiency is good at this mixing ratio.

The roast is then dissolved in water and solid-liquid separated. At this time, it is preferable to dissolve the roasted material at 70 to 90 ° C. At this time, if the temperature of the water is less than 70 ℃ low solubility of the carrier in water, if it exceeds 90 ℃ there is a problem that is not economical without increasing the dissolution rate.

Through this process, the spent catalyst carrier is converted to soluble so that it is dissolved in water and the platinum group metal remains as a residue. That is, when the strong acid is used as the flux, the alumina component of the alumina carrier is converted into soluble alum, and when the strong base is used as the flux, the alumina component of the alumina carrier is converted to soluble aluminum hydroxide and dissolved in water. It is separated from the platinum group metal.

The remaining platinum group metals are finally recovered by conventional wet and / or solvent extraction methods.

On the other hand, the alumina dissolving liquid is precipitated with aluminum hydroxide using aluminum hydroxide seed (seed) to recover aluminum hydroxide by filtering. This recovered aluminum hydroxide is reusable as aluminum.

Next, another method for recovering the platinum group metal from the spent catalyst of the present invention will be described.

The method for recovering the platinum group metal from the spent catalyst of the present invention,

In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal,

Firstly roasting the spent catalyst at 400 to 900 ° C. with a strong acid or strong base;

Dissolving the first roasted product in water and separating the first solid solution;

Mixing the strong base to the solid-liquid separated filtrate and then roasting at 400 to 900 ° C. for two times; And

And dissolving the secondary roasted product in water and separating the second solid solution.

First, the waste catalyst containing the platinum group metal and the strong acid or strong base are roasted at 400 to 900 ° C. Preferable roasting temperature (primary) is 400-600 degreeC. At this time, the waste catalyst can be used without grinding. Roasting is preferably carried out for 1 to 4 hours.

Subsequently, the first roasted material is dissolved in water and then solid-liquid separated.

Subsequently, the strong base is mixed with the solid-liquid separated filtrate and then secondary roasted at 400 to 900 ° C. Preferred roasting temperature (secondary) is 600 to 800 ° C. In this case, the mixing ratio of the first solid-liquid separation filtrate and the strong base is preferably 1: 1 to 1: 3 based on the equivalent ratio. A more preferable mixing ratio of the primary solid-liquid filtrate and the strong base is from 1: 1.2 to 1: 1.5.

Subsequently, the secondary roasted material is dissolved in water and then the second solid solution is separated. At this time, it is preferable to dissolve the roasted material at 70 to 90 ° C.

Through this process, the spent catalyst carrier is converted to soluble so that it is dissolved in water and the platinum group metal remains as a residue.

As in the present invention, the first, second, and two times of roasting may be performed to increase the solubilization rate of the insoluble carrier, thereby increasing the recovery rate of the platinum group metal contained in the spent catalyst.

In another method for recovering the platinum group metal from the waste catalyst of the present invention, the type of strong acid and strong base, the mixing ratio of the waste catalyst and the strong acid or strong base, and the like are applied in the same manner as described above.

In the present invention, the waste catalyst undergoes roasting process with a strong acid or strong base so that the poorly soluble alumina of the alumina carrier waste catalyst is converted into an insoluble platinum and / or aluminum hydroxide to be separated from the insoluble platinum group metal.

Hereinafter, the method for recovering the platinum group metal from the spent catalyst of the present invention will be described in more detail with reference to the following examples.

<Example 1>

100 g of alumina carrier waste catalyst (alpha-type or gamma-type) containing platinum group generated in a refinery and 120 g of NaOH were mixed, charged in a ball mill, and ground. The mixture of the spent catalyst and NaOH was placed in a porcelain crucible, charged into an roasting furnace, and roasted at 400 to 900 ° C. for 120 minutes. The roasted material was dissolved in water at 70 to 90 ° C., and then filtered to recover an insoluble residue and a platinum group concentrate. The dissolution rate (%) of the spent catalyst according to the roasting temperature is shown in Table 1.

400 ℃ 500 ℃ 600 ℃ 700 ℃ 800 ℃ 900 ℃ Gamma-type 92.45 93.91 95.48 95.01 94.43 80.58 Alpha-type 84.91 83.73 88.87 95.59 95.03 58.59

As can be seen in Table 1, the dissolution rate of the spent catalyst was found to be about 85 ~ 95%. Gamma-type alumina spent catalysts showed higher dissolution efficiency than alpha-type.

<Example 2>

15 ml, 20 ml and 25 ml of sulfuric acid were placed in a porcelain crucible and then roasted at 500 ° C. for 120 minutes in 10 g of alumina carrier waste catalyst containing platinum group. After cooling for 25 minutes, the solution was dissolved in water at 70-90 ° C. for 2 hours at 450 rpm, and then solid-liquid separated to recover an insoluble platinum group concentrate. Table 2 shows the dissolution rate (%) of the spent alumina carrier catalyst according to the amount of sulfuric acid added.

15 ml 20 ml 25 ml Gamma-type 71.22 73.00 76.70 Alpha-type 40.58 47.57 49.75

As can be seen in Table 2, the dissolution rate of the spent catalyst was found to be about 40 ~ 76%.

<Example 3>

100 g of NaOH was mixed with 100 g of the platinum group-containing alumina carrier spent catalyst generated in the refinery and then subjected to primary roasting at 400 ° C. for 2 hours. The primary roasted product was dissolved in water at 70-90 ° C. and then solid-liquid separation was performed. The ratio of this insoluble residue and NaOH was 1: 1.2, and the secondary roasting was performed at 700 ° C. for 2 hours. The secondary roast was then dissolved in water at 70-90 ° C. and filtered to recover the insoluble platinum group concentrate. The spent catalyst dissolution rate (%) after the primary roasting and the secondary roasting was measured and shown in Table 3.

Primary roasting rate (%) Secondary roasting dissolution rate (%) Gamma-type 70.47 99.45 Alpha-type 68.97 99.37

As can be seen from Table 3, it was confirmed that the rate of dissolution of the spent catalyst after the secondary roasting is significantly increased.

<Example 4>

100 g of alumina carrier waste catalyst containing platinum group and 150 ml of concentrated sulfuric acid (98%) were mixed in a refinery and then roasted at 500 ° C. for 2 hours. The primary roasted product was dissolved in water at 70-90 ° C. and then solid-liquid separation was performed. The ratio of this insoluble residue to NaOH was 1: 1.5, followed by secondary roasting at 700 ° C. for 3 hours. Subsequently, the secondary roast was dissolved in water at 70-90 ° C. and then subjected to solid-liquid separation to recover an insoluble platinum group concentrate. The waste catalyst dissolution rate (%) after the primary roasting and the secondary roasting was measured and shown in Table 4.

Primary roasting rate (%) Secondary roasting dissolution rate (%) Gamma-type 71.00 96.40 Alpha-type 43.67 95.22

As can be seen in Table 4, it was confirmed that the rate of dissolution of the spent catalyst after the secondary roasting was significantly increased.

Specific embodiments of the present invention have been presented above, but the present invention is not limited to the above, and various modifications can be made within the technical spirit of the present invention, and such modifications will belong to the following claims.

Claims (11)

In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal, The waste catalyst is mixed with a strong base selected from at least one selected from the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide in a ratio of 1: 1 to 1: 3 based on an equivalent ratio, and roasted at 400 to 900 ° C. for 1 to 4 hours, A method for recovering a platinum group metal from a spent catalyst, wherein the roasted product is dissolved in water and then subjected to solid-liquid separation to obtain an insoluble platinum group metal. delete The method according to claim 1, The method for recovering the platinum group metal from the spent catalyst, characterized in that the roasted water is dissolved in water of 70 to 90 ℃. delete The method according to claim 1, The roasting temperature is a method for recovering the platinum group metal from the waste catalyst, characterized in that 400 to 700 ℃. The method according to claim 1, The waste catalyst is a method for recovering the platinum group metal from the waste catalyst, characterized in that the alumina carrier. In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal, The waste catalyst is mixed with at least one strong acid selected from the group consisting of hydrochloric acid, sulfuric acid, and nitric acid in a ratio of 1: 1 to 1: 3 based on an equivalent ratio, and roasted at 400 to 900 ° C. for 1 to 4 hours. A method for recovering a platinum group metal from a waste catalyst characterized by dissolving water in water and then liquid-liquid separation to obtain an insoluble platinum group metal. In the method for recovering the platinum group metal from the spent catalyst containing the platinum group metal, The spent catalyst is a strong acid selected from at least one selected from the group consisting of hydrochloric acid, sulfuric acid and nitric acid, or a strong base selected from the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide, and 1: 1 to 1: based on the equivalent ratio. Mixing at 3 and roasting at 400 to 900 ° C. for 1 to 4 hours; Dissolving the first roasted material in water and then separating the first solid to obtain an insoluble matter; The solid-liquid separated filtration insolubles are mixed with at least one strong base selected from the group consisting of sodium hydroxide, potassium hydroxide and calcium hydroxide, 1: 1 to 1: 3 based on the equivalent ratio, and then 1 to 4 at 400 to 900 ° C. Secondary roasting for time; And Dissolving the secondary roasted product in water and then performing secondary solid-liquid separation to obtain an insoluble platinum group metal. The method of recovering a platinum group metal from a spent catalyst comprising: a. delete delete The method according to claim 8, The primary roasting temperature is 400 to 600 ℃, the secondary roasting temperature is a method for recovering the platinum group metal from the waste catalyst, characterized in that 600 to 800 ℃.