JPS6366370B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention aims to effectively utilize Ni from Ni-Sn-based waste catalysts, especially as a Ni source for stainless steel.
This invention relates to a method for separating and recovering Sn and Ni. In general, nickel sources used in the production of stainless steel include ferronickel, metallic nickel, nickel scrap, and nickel oxide. When used Ni-containing waste catalyst is directly used as raw material for making stainless steel, Fe, Cr, Ti, and
Mo, Mg, Ca and Cu and as supports
Although the presence of Al ₂ O ₃ and SiO ₂ is not particularly problematic, the presence of Sn is not desirable. Sn in steelmaking raw materials
They are hardly removed even during refining and remain in the steel, and they segregate significantly in large steel ingots, impairing hot workability and tending to impair the toughness of the steel. Therefore, in order to effectively utilize the Ni-Sn-based waste catalyst as a Ni source in stainless steel production, it is desired to establish a processing method for effectively separating and recovering Ni and Sn from the waste catalyst. Japanese Patent Publication No. 56-47254 discloses a method for separating and recovering valuable metals from waste catalysts. In the method of this patent publication, the catalyst is oxidized and roasted to remove S, and then subjected to alkaline roasting, water extraction, and filtration.
Mo, V, and even Ni, Co using a high-magnetic separator
, and Al, which is a carrier agent, is also recovered.
There is no mention of Sn. Therefore, an object of the present invention is to provide a method for substantially completely separating and recovering Ni and Sn from a Ni-Sn-based waste catalyst. According to the present invention, a Ni-Sn-based waste catalyst is digested with a non-oxidizing mineral acid, and the resulting liquid is deoxidized to a pH of 1.0 to 2.0.
It was found that the Sn content could be selectively separated as metastannic acid by curing with water. After separating the Sn component, the Ni component can be separated as nickel hydroxide.
The metastannic acid and nickel hydroxide are then converted to tin oxide and nickel oxide, respectively, by roasting, and if desired, the tin oxide and nickel oxide are further converted to metallic tin and metallic nickel, respectively, by reduction. In this way, Ni and Sn can be extracted from the Ni-Sn-based waste catalyst, which is made by supporting Ni and Sn on a ceramic carrier.
The method of the present invention for separating and recovering the catalyst includes the following steps (a) obtaining an acid solution containing dissolved Ni and Sn extracted by leaching the waste catalyst with a non-oxidizing mineral acid; b) A step of removing the acid content after removing the solid content from the acid solution in step (a); (c) A step of removing the acid content from the acid solution in step (b) to a pH of 1.0 to 2.0.
(d) solidifying the liquid containing metastannic acid suspended in step (c);
(e) Roasting the solid content obtained in step (d) to recover tin oxide; (f) Neutralizing the liquid obtained in step (d) with an alkali to produce hydroxide. a step of precipitating nickel; (g) a step of solid-liquid separation of the liquid containing suspended nickel hydroxide in step (f); and (h) a step of roasting and oxidizing the solid content obtained in step (g). and, if desired, (i) reducing the tin oxide recovered in step (e) to recover tin metal; and/or (j) reducing the nickel oxide recovered in step (h). The method may further include a step of reducing and recovering the nickel metal. The attached FIG. 1 is a flow sheet for explaining a preferred embodiment of the method of the present invention. The starting waste catalyst treated by the method of the present invention is a Ni-Sn-based waste catalyst in which Ni, Sn, and other metals are supported on a ceramic carrier such as alumina or alumina-silica, and its chemical composition is, for example, It can be as shown in Table 1.

[Table] Such waste catalysts are obtained, for example, from dehydrogenation processes in the petroleum refining industry. Referring to FIG. 1, the starting spent catalyst is preferably subjected to a pretreatment consisting of sieving 1, oxidative roasting 2 and grinding 3. That is, the starting spent catalyst is
After the carrier ceramic is removed as much as possible by sieving 1, it is subjected to oxidative roasting 2. This oxidation roasting 2 is a process for incinerating and removing oil and other organic substances adhering to the waste catalyst, and the roasting temperature is a temperature sufficient to ash the oil and other organic substances, for example, about 200℃. The temperature can be from ℃ to 800℃. In the pulverization step 3, the waste catalyst is, for example,
Pulverize to a particle size that can pass through a 150 mesh mill. In the method of the present invention, the starting waste catalyst is preferably subjected to the above-mentioned pretreatment and then leached with a non-oxidizing mineral acid to obtain an acid solution containing the extracted Ni and Sn dissolved therein. Suitable leaching acids 4 are non-acidic mineral acids such as hydrochloric acid, dilute sulfuric acid and phosphoric acid. When using an oxidizing acid such as nitric acid,
Since a portion of Sn is hydrolyzed, the extraction rate of Sn decreases. Hydrochloric acid was found to be most preferred for substantially complete extraction of Ni and Sn. In this leaching 5, the leaching acid 4 and the pretreated waste catalyst are fed into a steel leaching tank lined with FRP and equipped with appropriate stirring means and heating means, and the leaching acid 4 and the pretreated waste catalyst are stirred and mixed under heating. It is convenient to do this by In this case, the volume of the leaching tank is determined by the amount of waste catalyst to be treated and the treatment time. Alternatively, leaching can be carried out by repeatedly passing heated leaching acid through a column filled with spent catalyst. Leaching involves Ni and
It is preferable to use an amount approximately 2 to 7 times the stoichiometric amount required to dissolve the entire amount of Sn. If the amount of leaching acid used is too small, the extraction rate of Ni and Sn will decrease, and if the amount of leaching acid used is too large, the load in the subsequent acid removal step will become excessive. The concentration of the leaching acid used is preferably 1 part hydrochloric acid to 2 parts water, or 1 part hydrochloric acid to 3 parts water, and in the case of dilute sulfuric acid, 1 part sulfuric acid to 4 parts water or 1 part sulfuric acid to 6 parts water. The leaching concentration is
The temperature is preferably 65°C to 100°C, particularly 75°C to 90°C. When leaching is performed under the preferred conditions described herein, approximately 100% of the Ni and 98.8% or more of the Sn in the starting spent catalyst can be extracted. The acid solution containing dissolved Ni and Sn obtained by acid leaching is subjected to solid-liquid separation 6, for example, to remove the solid content 7, which consists of acid-insoluble alumina and silica.
remove. To give an example of the composition of the resulting solution 8, (for example, sample 4 shown in Table 1 is mixed with an amount equivalent to four times the stoichiometric amount required to dissolve the entire amount of Ni and Sn in the sample) ( Composition of the solution obtained by treatment with 4 mol) of hydrochloric acid), Ni; 22.1 g/,
Sn: 4.15 g/, free hydrochloric acid: 1.9 mol. In the next step of the method of the present invention, the free acid content is removed from the solution obtained in this way that contains the dissolved Ni and Sn content and also contains the free acid content. This acid removal step 9 is conveniently carried out by diffusion dialysis using an ion exchange membrane. When a volatile acid, such as hydrochloric acid, is used as the leaching acid, the acid content can also be removed by thermal distillation. The acid recovered from the acid removal step 9 is reused as leaching acid 4. The next step is Step 10, in which metastannic acid is precipitated by adjusting the pH of the acid-free solution to 1 to 2. PH adjustment is conveniently carried out by dilution with water. For the precipitation of metastannic acid, a pH of 1.0 or higher is required, but a pH of 2.0 is required.
If it substantially exceeds this, there is a problem that hydroxides of other metals will precipitate. In adjusting the pH, in order to facilitate the precipitation of metastannic acid, it is preferable to heat the solution to a temperature of, for example, 40°C to 50°C, and it is also preferable to add the oxidizing agent 11 and/or the inducing agent 12. . Examples of the oxidizing agent 11 include nitric acid, chlorate or hydrogen peroxide, and the amount of oxidizing agent 11 is 2 to 5 per 30 to 50 g of Sn present in the solution.
It is preferable to add such an oxidizing agent in an amount of .g. Oxygen and oxygen-containing gases, i.e. air, are also oxidizing agents 11
For example, per solution, air
It is also good to perform air ration at 0.2 to 0.3 N/min. As the metastannic acid nucleus generation inducing agent 12, tin salts such as stannous chloride, stannic chloride,
Sn30~50g/0.3~0.5g of tin sulfate etc.
It can be added in an amount of The liquid containing precipitated metastannic acid in suspension is solid.
Subjected to liquid separation 13. Solid-liquid separation can be performed by filtration, centrifugation or other suitable techniques. The obtained solid content 14 (metastannic acid) is roasted 15 to recover tin oxide 16. The roasting temperature can be about 800-1000°C. The solution 17 obtained by solid-liquid separation 13 is
For example, in the above example, it contains 21.66g/Ni and trace trace, and its pH is 1.2 to 1.4.
It was hot. This liquid 17 is neutralized 18 with an alkali 19 to precipitate nickel hydroxide. As the alkali 19, Ca(OH) ₂ , Na ₂ CO ₃ , NaOH and others can be used. The liquid containing nickel hydroxide in suspension is subjected to filtration or other solid-liquid separation 20, resulting in a solid content of 21
(Nickel hydroxide) is roasted 15 to recover nickel oxide 22. Roasting temperature is 800℃~1000℃
It can be ℃. On the other hand, the liquid 23 obtained from the solid-liquid separation 20 can be used to prepare the alkaline solution 19 for neutralization. The tin oxide 16 obtained by roasting 15 can be used as a chemical reagent as it is without purification, and if desired, it can be treated with H ₃ CO, C by a conventional method at a temperature of, for example, 500°C to 800°C. Metal tin 25 can also be obtained by reducing 24 with, for example, the following. Nickel oxide 22 obtained by roasting 15
can be used directly as a source of Ni in _stainless steel production, or if desired, it can be reduced by conventional methods, e.g. 24, it is also possible to use metal nickel 26. In this way, according to the method of the present invention, Ni-
Ni and Sn, which are valuable metals, can be effectively separated from Sn-based waste catalyst and recovered in high yield. Next, the method of the present invention will be further explained by giving specific examples. Example 1 The spent catalyst with the composition No. 3 shown in Table 1 was
The Ni in this waste catalyst is crushed into 100 to 150 mesh pieces.
and Digested with stirring at 80°C for 2 hours using an amount equivalent to 4 times the stoichiometric amount required to dissolve the entire amount of Sn, that is, 4 mol of hydrochloric acid (concentration 14.6%), and solidified. After separating Ni; 35.24g/,
An acid solution containing 2.37 g of Sn and 1.8 mol of free hydrochloric acid was obtained. This acid solution was passed through an ion exchange membrane with 40°C water flowing at a flow rate of 1.0/m ² hr.
By dialysis by flowing in the opposite direction at a flow rate of /m ² hr, deacidification was performed, and a deacidified solution and recovered acid were obtained. The composition of the obtained deoxidizing solution was Ni: 33.62 g/, Sn: 22.4
g/, 0.15 mol of free acid salt. The composition of the recovered acid was 1.62 g/Ni, 0.13 g/Sn, and 2.03 mol of free hydrochloric acid. Next, add this deoxidizing solution to 2
The colloid was diluted with twice the amount of water to bring the pH to 1.2 to 1.4, heated to about 45°C to complete the precipitation of metastannic acid, and cured by adding 2.5 g of stannous chloride crystals. β-metastannic acid was precipitated and solid-liquid separated by filtration. The precipitate was roasted at approximately 900°C to recover substantially pure tin oxide. The recovery rate was approximately 95%. Approximately 5% of the unrecovered material was transferred to the recovered acid side during ion exchange.
This Sn content is circulated as a leaching acid together with the recovered acid, so it is not carried away from the system. One solution was neutralized by adding Ca(OH) ₂ aqueous solution,
Nickel hydroxide is precipitated, removed, and about
Nickel oxide was recovered by roasting at 1000℃. The recovery rate was 95%. When the obtained tin oxide was reduced with hydrogen gas at a temperature of approximately 700°C, metallic tin was obtained with a conversion rate of 98.0%. In addition, the obtained nickel oxide was heated to about 700°C.
When reduced with hydrogen gas at a temperature of approximately
Metallic nickel was obtained with 100% conversion. When the above procedure was repeated except that deoxidation was carried out by a heated distillation method, substantially the same results were obtained.

[Brief explanation of drawings]

FIG. 1 is a flow sheet for explaining a preferred embodiment of the method of the present invention. In the figure, 1... sieving, 2... roasting, 3... crushing, 4... leaching acid, 5... leaching, 6... solid-liquid separation, 7... insoluble matter, 8... solution, 9... Acid content removal, 10... Metastannic acid curing, 11... Oxidizing agent,
12...Inducing agent, 13...Solid-liquid separation, 14...
Metastannic acid, 15...roasted, 16...tin oxide,
17... Solution, 18... Neutralization, 19... Alkali neutralizing agent, 20... Solid-liquid separation, 21... Nickel hydroxide, 22... Nickel oxide, 23... Solution,
24...reduction, 25...metal tin, 26...metal nickel.

Claims (1)

[Claims] 1. In separating and recovering Ni and Sn from a Ni-Sn-based waste catalyst formed by supporting Ni and Sn on a ceramic carrier, (a) leaching the waste catalyst with a non-oxidizing mineral acid; (b) remove the solid content from the acid solution in step (a) and then remove the acid content; (c) remove the acid content from the acid solution in step (b). The pH of the solution from which acid has been removed is 1.0 to 2.0.
(d) The liquid containing metastannic acid suspended in step (c) is solidified.
(e) Roast the solid content obtained in step (d) to recover tin oxide; (f) Neutralize the solution obtained in step (d) with an alkali to recover nickel hydroxide. (g) solid-liquid separation of the liquid containing suspended nickel hydroxide in step (f), and (h) roasting the solid content obtained in step (g) to recover nickel oxide. A method characterized by: