CN1280433C - Chlorination treatment process of Se contg. substance - Google Patents

Abstract

The present invention provides a chlorination treatment method for leaching and recovering Se-containing materials of platinum group metals. In a chlorine atmosphere, the raw materials containing Se, Te, and platinum group metals are chlorinated and volatilized to remove Se and Te; chloride salt is added to the treated product, and chlorination roasting is carried out in a chlorine atmosphere to further remove Se, Te, and make the platinum group metal into a soluble salt, and then leaching the treated product with water. According to the present invention, Se and Te can be efficiently removed from a raw material containing Se, Te, and platinum group metals, and platinum group metals can be leached and recovered.

Description

Chlorination treatment of Se-containing substances

technical field

The present invention relates to starting from a raw material (hereinafter referred to as Se content) containing Se, Te, and platinum group metals (Pt, Pd, Ru, Rh, Ir, Os), for example, from the bottom residue of a Se distillation column In the residue after drying (after the residual selenium is distilled and separated in the dry still, the obtained dry residue containing Se, Te, and platinum group metals (hereinafter referred to as the Se distillation tower dry residue)), A method that can effectively remove Se and Te and recover platinum group metals.

Background technique

Platinum group metals are very insoluble in all inorganic acids under normal conditions. In the past, the following methods have been used to dissolve these elements, that is, to dissolve these elements, the method of treating them with an alkali-melting inorganic acid in the presence of oxygen or an oxidizing agent; mixing metals such as Zn, Sn, Pb, and Cu and melting them , dissolving zinc etc. with hydrochloric acid or sulfuric acid to obtain the active fine powder, and then dissolving the active fine powder with aqua regia; converting the platinum group metal into Na _m MCl ₆ (M is a platinum group element, m is 2 or 3 ) soluble salt method.

Japanese Patent Application Laid-Open No. 2003-268457 (Patent Document 1) discloses adding a mixture of sodium hydroxide and sodium nitrate to a raw material containing Se and platinum group metals, performing melting and water leaching, and separating the liquid component containing Se and the liquid component containing platinum. method for residues of group metals. However, since Te is not contained in the raw material, there is no specific disclosure about the separation method of Te.

In addition, Japanese Unexamined Patent Publication No. 2-205635 (Patent Document 2) discloses mixing a processed product containing Ru or its oxide with a complex salt forming agent of chloride, and flowing out chlorine gas while heating to make Ru or its oxide into chlorine. compound, and after reacting with the complex salt forming agent of the chloride to become a Ru complex salt, the method of reclaiming Ru by dissolution and separation.

In addition, Patent No. 2505492 (Patent Document 3) discloses a method for dissolving Ir, heating the mixture of Ir monomer and metal chloride in a chlorine stream, and converting it into a metal salt of iridic acid chloride, which is characterized in that The transformation is carried out by adding carbon to the mixture.

However, there is no specific disclosure of a method for separating Se, Te from a raw material containing Se, Te, and platinum group metals, and simultaneously recovering all platinum group metals added with Pt, Pd, Rh, and Os.

[Patent Document 1] Japanese Patent Laid-Open No. 2003-268457

[Patent Document 2] Japanese Unexamined Patent Publication Hei 2-205635

[Patent Document 3] Patent No. 2505492

Contents of the invention

In view of the above facts, an object of the present invention is to provide a method for leaching and recovering all platinum group metals while effectively separating Se and Te from a raw material containing Se, Te, and platinum group metals.

That is, the present invention is as follows:

(1) A method for chlorination treatment of Se-containing substances, characterized in that: a raw material containing Se, Te, and platinum group metals (hereinafter referred to as Se-containing substances) is subjected to chlorination and volatilization treatment in a chlorine gas atmosphere to remove Se , Te; add chloride salt to the treated product, and carry out chlorination roasting treatment in a chlorine atmosphere to further remove Se and Te, make platinum group metals become soluble salts, and then leaching the processed product with water.

(2) The method for chlorination treatment of Se-containing materials according to the above (1), wherein the amount of chlorine used in the chlorination volatilization treatment is the necessary amount required for the chlorination reaction of Se, Te, and platinum group metals. 0.8-4 times, and the heating temperature is 600-900°C.

(3) The method for chlorination treatment of a Se-containing material according to the above (1), wherein a reducing agent is added in the chlorination roasting treatment.

(4) The method for chlorination treatment of Se-containing materials according to any one of the above (1) to (3), wherein sodium chloride is used as the chloride salt used in the chlorination roasting treatment, and carbon powder is used as the reducing agent. .

(5) The method for chlorination of Se-containing materials according to any one of (1) to (4) above, wherein the amount of sodium chloride added in the chlorination roasting treatment is soluble chlorine of platinum group metals The amount of carbon powder added is 0.5 to 12 times the amount required for platinum group metals.

(6) The method for chlorination treatment of Se-containing materials according to any one of the above (1) to (5), wherein the amount of chlorine used in the chlorination roasting treatment is Se, Te chlorination reaction, platinum 0.8 to 4 times the amount necessary for the soluble chlorination reaction of group metals, and the heating temperature is 700 to 900°C.

(7) The method for chlorination treatment of Se-containing materials according to any one of the above (1) to (6), wherein in the chlorination roasting treatment, a container made of carbon is used as a reducing agent, or a container formed into Carbon in the form of plates or rods is placed in the boiler instead of adding carbon powder.

(8) The method for chlorination of a Se-containing material according to any one of (1) to (7) above, wherein the leaching treatment is performed with warm water or dilute hydrochloric acid instead of the water leaching treatment.

(9) The method for chlorination of a Se-containing material according to any one of (1) to (8) above, wherein the raw material is sufficiently dried in advance in the chlorination volatilization treatment and the chlorination roasting treatment.

(10) The method for chlorination treatment of a Se-containing material according to any one of (1) to (9) above, wherein in the chlorination volatilization treatment, the temperature is maintained at 150 to 217° C. until the heating temperature is reached. 30 minutes to 3 hours.

(11) The method for chlorination treatment of a Se-containing material according to any one of (1) to (10) above, wherein in the chlorination volatilization treatment, the temperature is kept at 400 to 450° C. until the heating temperature is reached. 30 minutes to 3 hours.

(12) The method for chlorination treatment of Se-containing substances according to any one of the above (1) to (11), wherein, in the chlorination volatilization treatment and the chlorination roasting treatment, during the temperature rise process, the temperature maintenance process In the process of neutralization and temperature drop, set the chlorine gas atmosphere above 550°C.

According to the present invention as above:

(1) Se, Te can be efficiently removed from raw materials containing Se, Te, and platinum group metals, and platinum group metals can be leached and recovered.

(2) Pt, Pd, Ru, Rh, Ir, Os and other platinum group metals can be obtained with a high recovery rate of more than 90%.

Description of drawings

Fig. 1 is a flowchart showing an embodiment of the present invention.

Fig. 2 is a schematic diagram showing the temperature mode and ventilation gas mode of the chlorination volatilization treatment in Example 1 of the present invention.

Fig. 3 is a diagram showing an implementation method of Embodiment 2 of the present invention.

Fig. 4 is a flowchart of Comparative Example 1 of the present invention.

Detailed ways

The present invention will be described in detail below.

The object of the present invention is to remove Se and Te from raw materials containing Se, Te and platinum group metals, and to leach and recover platinum group metals.

For example, after copper electrolytic slime is decoppered by the usual method, Au is recovered by solvent extraction by chlorination leaching, and then Se is reduced with _SO2 and separated from the solution by filtration. In order to improve the purity of filtered Se, distillation is carried out, but some platinum group metals mixed in Se are recovered as Se distillation column dry solid residue (mainly Se, Pt, Pd, Ru, Rh, Ir). Or after Se is reduced, Te is also reduced, then for this reduction slag, use sodium hydroxide to leach Te and filter the residue, as containing undissolved Se, Te, platinum group metal Te reduction slag alkali leaching residue (mainly Se, Te , Ru, Rh, Ir) are recovered.

In the present invention, the dry solid residue of the Se distillation tower or the alkali leaching residue of the Te reduction slag is used as a raw material. If the raw material contains water, it will release water vapor when heated in the chlorine gas flow, which may temporarily reduce the partial pressure of chlorine gas or may form oxides, so it is best to dry it well in advance. The drying conditions are not particularly limited, and may be 100 to 120° C. for 6 to 15 hours. In addition, when using raw materials with very little moisture, the drying process can of course be omitted.

In the chlorine gas flow, the raw material is heated, heated, and chlorinated and volatilized, and the chlorides of Se and Te with high vapor pressure are removed, leaving platinum group metals. The melting point of Se is 217°C, and the melting point of Te is 450°C. If they are melted during the heating process, the raw material particles will be tightly bonded, and chlorine gas will not flow smoothly. Therefore, the temperature should be kept below the respective melting points, and in the form of chlorides. Remove most of Se and Te. The conditions for removing Se are a temperature of 150 to 217° C. and a holding time of 30 minutes to 3 hours. The conditions for removing Te are a temperature of 400 to 450° C. and a holding time of 30 minutes to 3 hours. Since part of Se and Te form selenium compounds and tellurium compounds, it is difficult to convert them into chlorides and remove them. In order to fully remove Se and Te, reheat to high temperature. The heating temperature is preferably 600 to 900°C, more preferably 700 to 800°C.

The reason for limiting the temperature range will be described below. The sublimation temperature of selenium chloride is 196°C and that of tellurium chloride is 414°C. If the treatment temperature is lower than 600°C, the removal rate of Se and Te will decrease. In addition, if it exceeds 900° C., generally, the chlorides of platinum group metals are partially volatilized due to their high vapor pressures, while the chlorides dissociate and become metals that are difficult to leach in water, so the recovery rate decreases.

The treatment time is not particularly limited, but is preferably 1 to 10 hours, more preferably 3 to 6 hours.

The amount of chlorine is preferably 0.8 to 4 times the amount necessary for the chlorination reaction of Se, Te, and platinum group metals. Regarding the removal effect of Se and Te, since the same effect can be obtained even in the chlorination roasting process, as long as the raw material and chlorine are in easy contact conditions, it is enough to use 0.8 times the necessary amount, and even if it is circulated 4 times The above is just to increase the consumption of chlorine. Since the chlorination reaction of Se and Te starts to rise gradually from a low temperature near room temperature, it is necessary to maintain a chlorine gas atmosphere during the temperature rise and heating maintenance. In addition, since chlorides of platinum group elements dissociate at a temperature above 550° C. to release chlorine, it is necessary to maintain a chlorine gas atmosphere. Since chlorine gas is not consumed during cooling, the minimum amount of chlorine gas necessary to maintain the chlorine gas atmosphere can be used. When the temperature during cooling is below 500° C., it can also be replaced with an inert gas such as nitrogen or argon. In addition, if air is mixed into the chlorine gas atmosphere, the surface of the platinum group metal will be oxidized, and the reduction of the oxide layer cannot be caused even if mixed with carbon, resulting in a decrease in the recovery rate. Therefore, it is preferable to maintain strict airtightness.

The main reaction of chlorination volatilization treatment is as follows.

( )

Then, add sodium chloride and carbon powder to the treated product, and heat under the condition of circulating chlorine gas flow, carry out chlorination roasting treatment, then Se and Te remaining in the chlorination volatilization treatment are removed as chlorides again, The platinum group metals become soluble salts. The heating temperature is preferably 700 to 900°C, more preferably 750 to 850°C.

If the treatment temperature is lower than 700°C, not only the removal rate of Se and Te will decrease, but also the soluble chlorination reaction of platinum group metals will not proceed sufficiently and the yield will decrease; if it exceeds 900°C, the recovery rate will decrease due to a part of it volatilizing .

The treatment time is not particularly limited, but is preferably 1 to 10 hours, more preferably 3 to 6 hours.

The amount of chlorine is preferably 0.8 to 4 times the amount necessary for the chlorination reaction of Se and Te and the soluble chlorination reaction of platinum group metals. In addition, since chlorination is also carried out in the chlorination volatilization process, it is sufficient to use 0.8 times the necessary amount when the raw material and chlorine are easily contacted.

The amount of sodium chloride added is preferably 1 to 7 times the amount necessary for the soluble chlorination reaction of platinum group metals. In addition, if the addition amount of sodium chloride increases, the ratio of the chlorinated volatilized matter relative to the total amount that can be loaded into the furnace will decrease, and the treatment efficiency will decrease, so the range of 3 to 5 times is more preferable. Since commercially available sodium chloride contains moisture, it is preferably used after being sufficiently dried. The drying conditions are not particularly limited, and may be 100 to 150° C. for 6 to 15 hours.

The amount of carbon powder added is preferably 0.5 to 12 times the amount necessary to suppress oxidation of platinum group metals. Carbon powder can reduce the oxide layer on the surface of platinum group metals to promote the soluble chlorination reaction, and can inhibit the formation of oxide layer during the heating process, but even if it is added in an amount exceeding 12 times, there is almost no change in effect. In addition, instead of adding carbon powder, a container made of carbon can be used as a reducing agent, or carbon shaped into a plate or rod can be placed in the boiler to obtain the same effect as when adding carbon powder. In addition, if the amount of oxygen mixed in the furnace is reduced during the chlorination roasting treatment, it is of course possible to reduce the amount of carbon powder added. Since commercially available sodium chloride and carbon powder contain moisture, it is preferable to fully dry them before mixing with chlorinated volatiles and performing chlorination roasting. The drying conditions are not particularly limited, and may be 100 to 120° C. for 6 to 15 hours. In addition, use sodium chloride and carbon powder, which have little water content, and mix them with chlorinated volatiles in a state where no water is mixed, so that the drying process can be omitted.

In the case where the soluble chlorination reaction of platinum group metals is insufficient, the yield is reduced, and the recovery rate during water leaching is low, it can be crushed by crushing the treated product after chlorination and roasting, and repeating several times in the chlorine gas flow The operation of heating in the middle increases the recovery rate.

Hereinafter, the main reactions of the chlorination roasting treatment will be shown in the case of using sodium chloride as an example of the chloride salt.

( )

Thereafter, water leaches out the treatment, leaching out the soluble salts of the platinum group metals. The conditions at this time are not particularly limited, but warm water or dilute hydrochloric acid is preferable.

The temperature of warm water is preferably 50 to 90°C.

With regard to the concentration of dilute hydrochloric acid, even when only the water leaching is performed on the treated product, hydrochloric acid may become acidic due to free chlorine. Therefore, it is preferable to adjust to 0.5-1.5N as needed.

Filtrating residues containing excess sodium chloride, unreacted carbon powder, and unreacted platinum group metals, etc., to obtain a leach solution of platinum group metals. The platinum group metal is recovered as a sponge from the leach solution of the platinum group metal by a usual method. By returning the filter residue to the chlorination and roasting treatment process, the recovery rate of unrecovered platinum group metals can be increased and the amount of chemicals used can be reduced.

(Example 1)

This embodiment is implemented according to the process shown in FIG. 1 . Below, based on Table 1 and FIG. 2, it demonstrates concretely.

150 g of the dry solid residue of the Se distillation tower after being dried for 12 hours in a drier set at 100° C. was put into an evaporating dish made of quartz, and in a tubular furnace whose furnace core tube was made of quartz, the Chlorine gas is circulated in the same way, while maintaining at 200°C and 440°C for 1 hour respectively, and then heated to 700°C, and the amount of chlorine twice that required for the chlorination reaction of Se, Te, and platinum group metals is circulated for 5 hours. Chlorination volatilization treatment. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered. 83% of Se and 99% of Te were removed.

Then, add 170 g of sodium chloride of 3 times the amount required for the soluble chlorination reaction of platinum group metals to the treated product, and 3.2 g of carbon powder necessary for suppressing the oxidation of platinum group metals, and fully mix. This substance was dried for 12 hours in a dryer set at 100°C. After drying, put it into a quartz evaporating dish, and heat it to 850°C while flowing chlorine gas in a tubular furnace made of quartz, and flow twice as much as the chlorination reaction of Se and Te and the soluble chlorination of platinum group metals. React the required amount of chlorine, carry out the chlorination roasting treatment of 3 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the treated product was leached with 420 mL at a temperature of 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals. As shown in Table 1, Se in the leaching solution is 19 mg/L, Te is less than 0.1 mg/L, and more than 99% are removed from the dry solid residue of the Se distillation tower.

As shown in Table 1, the distribution ratios of platinum group metals are Pt92%, Pd90%, Ru90%, Rh93%, and Ir95%. Although Os is not contained in the raw material, it can be recovered in the same manner because it has very similar properties to Ru.

Table 1

(Example 2)

Example 2 will be described below. Except that the amount of chlorine used in the chlorination volatilization process is the necessary amount for the chlorination reaction of Se, Te, and platinum group metals, and the addition of carbon powder in the chlorination roasting process is changed in the manner shown in Figure 3 Except amount, adding method, others are identical with embodiment 1.

Put 6,000 g of the dry solid residue of the Se distillation tower dried in a drier set at 100° C. for 12 hours into an evaporating dish made of quartz, and in a tubular furnace whose furnace core tube is made of quartz, circulate chlorine gas at 200 Keep at ℃ and 440℃ for 1 hour respectively, then heat to 700℃, flow the necessary amount of chlorine required for the chlorination reaction of Se, Te, and platinum group metals, and perform chlorination and volatilization treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Next, 104 g of sodium chloride was added to 30 g of the processed product and mixed well with an amount five times the amount required for the soluble chlorination reaction of the platinum group metal. The material was dried in a dryer set at 100°C for 12 hours. Here, prepare (1) add 1 times the amount of carbon powder necessary to suppress the oxidation of platinum group metals; (2) add 10 times the amount of carbon powder; (3) put in a carbon plate; (4) A sample put into a quartz crucible as a carbon lid; (5) A sample put into a carbon crucible; and then heated to 850°C while circulating chlorine gas in a tubular furnace whose core tube is made of quartz , flow twice the amount of chlorine required for the chlorination reaction of Se and Te and the soluble chlorination reaction of platinum group metals, and carry out the chlorination roasting treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals.

The residue is filtered to obtain the leaching solution of platinum group metals. As shown in Table 2, extremely high distribution ratios were shown for all of Pt, Pd, Ru, Rh, and Ir. In particular, in the case of using the carbon crucible of (5), the distribution rate reached 99% or more for all metals.

There is little change in the effect when adding more than 12 times the amount of toner. In addition, by using a carbon container as a reducing agent or putting carbon shaped into a plate or rod into the boiler instead of adding carbon powder, the same or better effects than when adding carbon powder can be obtained.

Table 2

(Example 3)

Embodiment 3 will be specifically described based on Table 3 below. As the raw material, the above-mentioned Te reduction slag alkali leaching residue was used.

Put 6,000 g of the Te reduction slag alkali leaching residue dried in a drier set at 100°C for 12 hours into a quartz evaporating dish, and in a tubular furnace whose furnace core tube is made of quartz, circulate chlorine gas at 200 ℃ and 440 ℃ for 1 hour respectively, and then heated to 780 ℃, the amount of chlorine twice that required for the chlorination reaction of Se, Te, and platinum group metals was passed through, and the chlorination and volatilization treatment was carried out for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered. Both Se and Te were removed by more than 99%.

Next, 7500 g of sodium chloride, which is 5 times the amount required for the soluble chlorination reaction of platinum group metals, and 204 g of carbon, which is twice the amount required for suppressing the oxidation of platinum group metals, were added to 2650 g of the treated product. powder and mix well. The material was dried in a dryer set at 100°C for 12 hours. After drying, put it into a quartz evaporating dish, and heat it to 780°C while flowing chlorine gas in a tubular furnace made of quartz, and flow 1.9 times the chlorination reaction of Se and Te and the solubility of platinum group metals. The amount of chlorine required for the chlorination reaction was carried out for 5 hours of chlorination roasting treatment. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the treated product was leached with 22 L of warm water at 80° C. to leach soluble salts of platinum group metals. The residue was filtered to obtain 21.7 L of leach solution of platinum group metals. As shown in Table 3, the Se in the leaching solution is 22 mg/L, and the Te is 34 mg/L or less, and more than 99.9% are removed from the Te reduction slag alkali leaching residue.

As shown in Table 3, the distribution ratios of the platinum group metals were Pt98%, Pd95%, Ru96%, Rh99%, and Ir92%. Even if the characteristics of raw materials are different, Se and Te can be separated, and the platinum group metals in the leachate can be recovered with an efficiency of more than 90%.

table 3

(comparative example 1)

Next, Comparative Example 1 will be described based on Table 4 and FIG. 4 . In the absence of chlorination and volatilization treatment, sodium chloride and carbon powder were added to the dry solid residue of Se distillation tower, and the leaching solution of platinum group metals was obtained only through chlorination roasting treatment.

Add 750 g of sodium chloride 10 times the amount required for the soluble chlorination reaction of platinum group metals to 150 g of the dry solid residue of the Se distillation tower, and 2.8 g of carbon powder necessary for suppressing the oxidation of platinum group metals, and mix well. This substance was dried for 12 hours in a dryer set at 100°C. After drying, put it into a quartz evaporating dish, and heat it to 850°C while flowing chlorine gas in a tubular furnace made of quartz, and flow twice as much as the chlorination reaction of Se and Te and the soluble chlorination of platinum group metals. React the required amount of chlorine, carry out the chlorination roasting treatment of 3 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the soluble salt of the platinum group metal was leached with 825 mL of warm water at 80°C. The residue is filtered to obtain the leaching solution of platinum group metals.

As shown in Table 4, Se in the leaching solution is 13 mg/L, Te is less than 0.1 mg/L, and more than 99% are removed from the dry solid residue of the Se distillation tower.

As shown in Table 4, the distribution ratios of platinum group metals were Pt84%, Pd93%, Ru59%, Rh80%, and Ir70%. Compared with the Examples, it is found that the distribution rate of the platinum group metal is lowered, which is not ideal. Since the chlorination volatilization treatment is not performed, the chlorination reaction of Se and Te proceeds preferentially, and the soluble chlorination reaction of platinum group metals does not proceed sufficiently, resulting in a decrease in yield.

Table 4

(comparative example 2)

Next, based on Table 5, Comparative Example 2 will be described. Except that the treatment temperature of the chlorination volatilization treatment was set at 500° C., the others were the same as in Example 1.

150 g of the dry solid residue of the Se distillation tower after drying in a drier set at 100° C. for 12 hours was put into an evaporating dish made of quartz, and in a tubular furnace whose core tube was made of quartz, chlorine gas was circulated at 200 ° C. Keep at ℃ and 440℃ for 1 hour respectively, then heat to 500℃, flow chlorine twice the amount required for the chlorination reaction of Se, Te, and platinum group metals, and perform chlorination and volatilization treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered. As shown in Table 5, compared with Examples, 43% of Se and 27% of Te were removed, and the removal rate was low, so it was not ideal.

table 5

(comparative example 3)

Comparative Example 3 will be described below. Except that the amount of chlorine used in the chlorination volatilization process is twice the amount required for the chlorination reaction of Se, Te, and platinum group metals, and no carbon powder is added in the chlorination roasting process, other and implementation Example 2 is the same.

Put 150 g of the dry solid residue of the Se distillation tower dried in a drier set at 100°C for 12 hours into an evaporating dish made of quartz. Keep at 440°C for 1 hour, then heat to 700°C, flow chlorine twice as much as necessary for the chlorination reaction of Se, Te, and platinum group metals, and perform chlorination and volatilization treatment for 5 hours.

Next, 281 g of sodium chloride was added to the treated product in an amount seven times larger than that required for the soluble chlorination reaction of platinum group metals, and mixed well. No toner is added here. The material was dried in a dryer set at 100°C for 12 hours. After drying, put the material into an evaporating dish made of quartz, and heat it to 850°C while flowing chlorine gas in a tubular furnace made of quartz, and flow twice as much as the chlorination reaction of Se and Te and the gas of platinum group metals. The amount of chlorine required for the soluble chlorination reaction is carried out for 3 hours of chlorination roasting treatment. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, 359 mL of the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals. As shown in Table 6, Se in the leaching solution is less than 0.1 mg/L, Te is less than 0.1 mg/L, and more than 99% are removed from the Se distillation tower.

As shown in Table 6, the distribution ratios of platinum group metals were Pt85%, Pd89%, Ru55%, Rh82%, and Ir80%. Compared with the examples, it can be seen that the distribution rate of the platinum group metal is lowered, which is not ideal. Since no carbon powder is added, the reduction of the oxide layer on the surface of the platinum group metal cannot be carried out and the formation of the oxide layer cannot be suppressed during the heating process, so that the soluble chlorination reaction of the platinum group metal is insufficient and the yield is reduced.

Table 6

(comparative example 4)

Comparative Example 4 will be described below based on Table 7. It was the same as Example 2 except that the amount of carbon powder added in the chlorination roasting treatment was 0.1 times the amount necessary to suppress the oxidation of platinum group metals.

Put 6,000 g of the dry solid residue of the Se distillation tower dried in a drier set at 100° C. for 12 hours into an evaporating dish made of quartz, and in a tubular furnace whose furnace core tube is made of quartz, circulate chlorine gas at 200 Keep at ℃ and 440℃ for 1 hour respectively, then heat to 700℃, flow the necessary amount of chlorine required for the chlorination reaction of Se, Te, and platinum group metals, and perform chlorination and volatilization treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Next, 104 g of sodium chloride, 5 times the amount required for the soluble chlorination reaction of platinum group metals, and 0.12 g of carbon powder, 0.1 times the amount required to suppress the oxidation of platinum group metals, were added to 30 g of the treated product. , and mix well. The material was dried in a dryer set at 100°C for 12 hours. After drying, heat to 850°C while circulating chlorine gas in a tubular furnace whose core tube is made of quartz, and circulate twice the amount of chlorine required for the chlorination reaction of Se and Te and the soluble chlorination reaction of platinum group metals, The chlorination roasting treatment was carried out for 5 hours. In addition, the nitrogen gas was replaced at 500° C. when the temperature was lowered.

Thereafter, the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals.

As shown in Table 7, the distribution ratios of platinum group metals were Pt81%, Pd68%, Ru67%, and Rh49%. Compared with Example 2, it can be seen that the distribution rate of the platinum group metal is lowered, which is not ideal. Adding less than 0.5 times the amount of toner has almost no effect. Like when no carbon powder is added, the reduction of the oxide layer on the surface of the platinum group metal and the suppression of the formation of the oxide layer during the heating process cannot be performed or sufficiently performed, so that the soluble chlorination reaction of the platinum group metal is insufficient and the yield is reduced .

Table 7

(comparative example 5)

Comparative Example 5 will be described below based on Table 8. Here, it was directly used without dry raw material and sodium chloride, and compared with Example 2.

6000 g of the undried Se distillation tower dry solid residue was charged into an evaporating dish made of quartz, and kept at 200° C. and 440° C. for 1 hour respectively in a tubular furnace whose furnace core tube was made of quartz, while circulating chlorine gas. Heating to 700°C, flowing the necessary amount of chlorine required for the chlorination reaction of Se, Te, and platinum group metals, and performing chlorination and volatilization treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Next, 5780 g of sodium chloride, which is commercially available and not dried, is 5 times the amount required for the soluble chlorination reaction of platinum group metals, is added to 1730 g of the processed product, and 10 times the amount necessary to suppress the oxidation of platinum group metals is added. Measure 696g of toner and mix well. Here, the material is not dried, but is directly heated to 850°C in a tubular furnace whose core tube is made of quartz, while flowing chlorine gas, and the chlorination reaction of Se and Te is twice as large as that of soluble chlorination of platinum group metals. React the required amount of chlorine, carry out the chlorination roasting treatment of 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals.

As shown in Table 8, the results are Pt9%, Pd99% or more, Ru51%, Rh94%, Ir53%, compared with Example 2, it can be seen that the distribution ratio of Pt, Ru, and Ir is lowered, which is not ideal. As a result of X-ray diffraction measurement of the leaching residue, oxides of platinum group metals were detected. Since the raw material contains a lot of water, the oxides formed during the heating process cannot be fully reduced by the carbon powder. As a result, the soluble chlorination reaction of platinum group metals is insufficient and the yield is reduced.

Table 8

(comparative example 6)

Comparative Example 6 will be described below based on Table 9. Here, in the chlorination roasting step, the heating temperature was continuously raised to 700° C. for comparison.

Put 6,000 g of the dry solid residue of the Se distillation tower dried in a drier set at 100°C for 12 hours into an evaporating dish made of quartz. Continuously raise the temperature to 700°C, flow the necessary amount of chlorine required for the chlorination reaction of Se, Te, and platinum group metals, and perform chlorination and volatilization treatment for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Then, add 5 times the sodium chloride of 5770g of the amount required for the soluble chlorination reaction of platinum group metals to this processed object 1741g, and the carbon powder of 70g of necessary amount required for suppressing the oxidation of platinum group metals, and fully mix. The material was dried in a dryer set at 100°C for 12 hours. After drying, heat to 850°C while circulating chlorine gas in a tubular furnace whose core tube is made of quartz, and circulate twice the amount of chlorine required for the chlorination reaction of Se and Te and the soluble chlorination reaction of platinum group metals, The chlorination roasting treatment was carried out for 5 hours. In addition, nitrogen gas was replaced at 500°C when the temperature was lowered.

Thereafter, the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals.

As shown in Table 9, the results are Pt71%, Pd81% or more, Ru99%, Rh99% or more, and Ir97%. Compared with Example 2, it can be seen that the distribution ratio of Pt and Pd is lowered, which is not ideal. As a result of X-ray diffraction measurement of the leaching residue, platinum group metals in a metallic state were detected. This is because a large amount of Se contained in the raw material is melted during the temperature rise, and the particles of the raw material are closely bonded, so that chlorine gas cannot flow smoothly, and as a result, the soluble chlorination reaction of the platinum group metal does not proceed sufficiently and the yield decreases.

Table 9

(comparative example 7)

Comparative Example 7 will be described below based on Table 10. Here, in the chlorination volatilization process and the chlorination roasting process, a comparison was made by replacing the atmospheric gas from chlorine to nitrogen immediately after the start of temperature drop after holding at the heating temperature for a predetermined time.

Put 6,000 g of the dry solid residue of the Se distillation tower dried in a drier set at 100°C for 12 hours into an evaporating dish made of quartz. Continuously raise the temperature to 700°C, flow the necessary amount of chlorine required for the chlorination reaction of Se, Te, and platinum group metals, carry out the chlorination and volatilization treatment for 5 hours, and flow nitrogen gas immediately after starting to lower the temperature.

Next, 4360 g of sodium chloride, 5 times the amount required for the soluble chlorination reaction of platinum group metals, and 525 g of carbon powder, 10 times the amount required to suppress the oxidation of platinum group metals, were added to 1741 g of the processed product. , and mix well. The material was dried in a dryer set at 100°C for 12 hours. After drying, heat to 820°C while circulating chlorine gas in a tubular furnace whose core tube is made of quartz, and circulate twice the amount of chlorine required for the chlorination reaction of Se and Te and the soluble chlorination reaction of platinum group metals, The chlorination roasting treatment was performed for 5 hours, and nitrogen gas was flowed immediately after the temperature drop was started.

Thereafter, the treated product was leached with warm water at 80° C. to leach soluble salts of platinum group metals. The residue is filtered to obtain the leaching solution of platinum group metals.

As shown in Table 10, the results are Pt52%, Pd57%, Ru68%, Rh72%, Ir64%. Compared with Example 2, it can be seen that the distribution rate of platinum group metals is lowered, which is not ideal. As a result of X-ray diffraction measurement of the leaching residue, platinum group metals in a metallic state were detected. This is because the chlorides of platinum group elements will dissociate and release chlorine at a temperature above 550°C, and nitrogen gas is directly circulated at high temperature during the cooling process here, resulting in a decrease in the partial pressure of chlorine, thereby decomposing into metal state. platinum group metals. As a result, the soluble chlorides of the platinum group metals decrease, and the yield decreases.

Table 10

Claims (12)

1. a kind of Se, Te and the chlorination treatment method of platinum group metal content, it is characterized in that: In a chlorine atmosphere, the raw materials containing Se, Te, and platinum group metals are chlorinated and volatilized to remove Se and Te; chloride salt is added to the treated product, and chlorination roasting is carried out in a chlorine atmosphere to further remove Se and Te make platinum group metals into soluble salts, and then water leaching the treated product, thereby leaching and recovering platinum group metals. 2. Se, Te as claimed in claim 1, and the chlorination treatment method of platinum group metal content, it is characterized in that: The amount of chlorine used in the chlorination and volatilization treatment is 0.8 to 4 times the amount necessary for the chlorination of Se, Te, and platinum group metals, and the heating temperature is 600 to 900°C. 3. Se, Te as claimed in claim 1, and the chlorination treatment method of platinum group metal content, it is characterized in that: In the chlorination roasting treatment, a container made of carbon is used as a reducing agent, or carbon powder is added or carbon formed into a plate shape or a rod shape is used. 4. Se, Te as claimed in claim 3, and the chlorination treatment method of platinum group metal content, it is characterized in that: Sodium chloride is used as the chloride salt used in the chlorination roasting treatment, and carbon powder is used as the reducing agent. 5. Se, Te as claimed in claim 4, and the chlorination treatment method of platinum group metal containing thing, it is characterized in that: The amount of sodium chloride used in the chlorination roasting process is 1 to 7 times the amount required for the soluble chlorination of platinum group metals, and the amount of carbon powder added is the necessary amount for platinum group metals. 0.5 to 12 times the amount. 6. Se, Te as described in any one in claim 1～5, and the chlorination treatment method of platinum group metal content, it is characterized in that: The amount of chlorine used in the chlorination roasting treatment is 0.8 to 4 times the amount necessary for the chlorination of Se and Te and the soluble chlorination of platinum group metals, and the heating temperature is 700 to 900°C. 7. Se, Te as claimed in claim 5, and the chlorination treatment method of platinum group metal content, it is characterized in that: In the chlorination roasting treatment, instead of adding carbon powder, a container made of carbon is used as a reducing agent, or carbon shaped into a plate or rod is placed in a boiler. 8. Se, Te as described in any one in claim 1～5, and the chlorination treatment method of platinum group metal content, it is characterized in that: Use warm water or dilute hydrochloric acid for leaching instead of water leaching. 9. Se, Te as described in any one in claim 1～5, and the chlorination treatment method of platinum group metal content, it is characterized in that: In the above-mentioned chlorination volatilization treatment and chlorination roasting treatment, the raw material is fully dried in advance. 10. Se, Te as claimed in claim 2, and the chlorination treatment method of platinum group metal content, it is characterized in that: In the chlorination volatilization treatment, the temperature is maintained at 150 to 217° C. for 30 minutes to 3 hours until the heating temperature is reached. 11. Se, Te as claimed in claim 2, and the chlorination treatment method of platinum group metal content, it is characterized in that: In the above-mentioned chlorination volatilization treatment, it is kept at 400-450° C. for 30 minutes to 3 hours until the heating temperature is reached. 12. Se, Te as described in any one in claim 1～5, and the chlorination treatment method of platinum group metal content, it is characterized in that: During the temperature rise process, temperature maintenance process, and temperature drop process of the chlorination volatilization treatment and chlorination roasting treatment, a chlorine gas atmosphere of 550° C. or higher is set.

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