阅读说明：本技术 一种汽车尾气废催化剂浸出贵液中铁的分离方法 (Separation method for iron in precious solution leached by automobile exhaust waste catalyst ) 是由 许开华 肖力 李琴香 张坤 华文超 苏陶贵 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种汽车尾气废催化剂浸出贵液中铁的分离方法,包括以下步骤：1)采用连续水解法,将液碱和贵液同时加入到反应釜中,控制溶液pH值及温度料,反应完成后过滤,得到第一滤饼；2)将第一滤饼用稀盐酸溶液洗涤,控制pH值及温度,搅拌洗涤,过滤得到第二滤饼；3)将第二滤饼重新用盐酸溶解,控制pH值及温度,加入亚硝酸钠,贵金属亚硝酸根充分络合后,再次控制pH水解,反应结束后过滤,得到第三滤饼。本发明能够将铁分离彻底,对于铁离子浓度在100g/L以下的贵液,采用本方法均可以将贵液中铁离子降低至10mg/L以下,完全满足铂钯铑精炼对杂质含量要求。本发明贵金属回收率高且成本低,本工艺铂钯回收率均在99％以上,铑回收率达95％以上。(The invention discloses a separation method of iron in precious liquid leached by a waste catalyst in automobile exhaust, which comprises the following steps: 1) adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value and temperature of the solution, and filtering after the reaction is finished to obtain a first filter cake; 2) washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value and the temperature, stirring and washing, and filtering to obtain a second filter cake; 3) and dissolving the second filter cake with hydrochloric acid again, controlling the pH value and the temperature, adding sodium nitrite, fully complexing with noble metal nitrite, controlling the pH value again for hydrolysis, and filtering after the reaction is finished to obtain a third filter cake. The method can completely separate iron, and for the pregnant solution with the iron ion concentration of less than 100g/L, the method can reduce the iron ion content of the pregnant solution to less than 10mg/L, thereby completely meeting the requirements of platinum-palladium-rhodium refining on impurity content. The method has the advantages of high recovery rate of noble metals and low cost, the recovery rate of platinum and palladium is more than 99%, and the recovery rate of rhodium is more than 95%.)

1. A separation method of iron in precious solution leached by a waste catalyst in automobile exhaust is characterized by comprising the following steps:

1) a hydrolysis method: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.5-3.0, controlling the temperature to be 60-100 ℃, reacting for 30-120 min after the feed liquid is added, controlling the pH value of the solution to be 2.5-3.0 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.5-3.0, controlling the temperature to be 60-100 ℃, stirring and washing for 30-120 min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake with hydrochloric acid again, just dissolving the filter cake with added hydrochloric acid, adjusting the pH to 0.5-1.5 with liquid alkali, heating the slurry to 70-100 ℃, adding sodium nitrite, reacting for 30-60 min, adding liquid alkali to adjust the pH to 2.5-3.0 after the noble metal is fully complexed with nitrite, maintaining for 30-120 min, and filtering after the reaction is finished to obtain a third filter cake and filtrate.

2. The separation method of iron in the precious liquid leached by the automobile exhaust spent catalyst according to claim 1, characterized in that the addition amount of sodium nitrite is 1-10 times of the mass of precious metals, and the reaction time is 30-120 min.

Technical Field

The invention belongs to a hydrometallurgy plate, and particularly relates to a separation method of iron in precious liquid leached by a waste catalyst in automobile exhaust.

Background

The recovery process of the platinum, palladium and rhodium in the automobile waste catalyst comprises a pyrogenic process and a wet process, wherein the pyrogenic process is widely applied due to strong adaptability, stable recovery rate and large treatment capacity. The iron trapping process is one of the most commonly used pyrometallurgical processes, and by using this process, platinum, palladium, rhodium can be enriched in iron alloys, while the spent catalyst carriers are removed by slagging. In order to obtain the platinum-palladium-rhodium pregnant solution with low impurity content, most of iron in the iron alloy is usually removed by adopting an acid leaching method to obtain platinum-palladium-rhodium concentrate, and then aqua regia is used for leaching to obtain the pregnant solution. Because the acid leaching method is difficult to completely remove iron, the concentration of iron ions in the pregnant solution is still very high, and the subsequent separation and refining of platinum, palladium and rhodium are influenced. Conventional separation methods include reduction, displacement and precipitation. The reduction method uses hydrazine hydrate or sodium borohydride as a reducing agent, and has the defects that the reduction rate of rhodium is very low under an acidic condition, and 15 to 26 percent of iron is reduced; the replacement method utilizes zinc powder or magnesium powder to replace noble metal, and has the defects of large consumption of the zinc powder or the magnesium powder and higher cost; the precipitation method for precipitating platinum group metals by using thiourea or sodium sulfide is determined by long flow, large energy consumption, and difficulty in filtration due to too fine sulfide precipitate.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for separating iron in precious liquid leached by a waste catalyst in automobile exhaust.

The invention is realized by the following technical scheme.

A separation method of iron in precious liquid leached by a waste catalyst in automobile exhaust comprises the following steps:

1) a hydrolysis method: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.5-3.0, controlling the temperature to be 60-100 ℃, reacting for 30-120 min after the feed liquid is added, controlling the pH value of the solution to be 2.5-3.0 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.5-1.5, controlling the temperature to be 60-100 ℃, stirring and washing for 30-120 min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake with hydrochloric acid again, just dissolving the filter cake with added hydrochloric acid, adjusting the pH to 0.5-1.5 with liquid alkali, heating the slurry to 70-100 ℃, adding sodium nitrite, reacting for 30-60 min, adding liquid alkali to adjust the pH to 2.5-3.0 after the noble metal is fully complexed with nitrite, controlling the pH value of the feed liquid to 2.5-3.0 after the pH adjustment with liquid alkali is finished, maintaining for 30-120 min, and filtering after the reaction is finished to obtain a third filter cake (ferric hydroxide slag) and a filtrate which are basically free of noble metal.

In the invention, the adding amount of the sodium nitrite is calculated according to 1-10 times of the mass of the noble metal, and the reaction time is 30-120 min.

The invention has the beneficial technical effects that:

1. the iron is separated thoroughly, and for the pregnant solution with the iron ion concentration below 100g/L, the iron ion in the pregnant solution can be reduced to below 10mg/L by adopting the method, so that the requirement of platinum-palladium-rhodium refining on the impurity content is completely met;

2. the recovery rate of the noble metal is high, the recovery rates of the platinum and the palladium in the process are all over 99 percent, and the recovery rate of the rhodium is over 95 percent;

3. the process cost is low, and the needed liquid caustic soda and sodium nitrite are cheap and easily available industrial raw materials.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

Example 1

The components of a noble liquid are shown in Table 1

TABLE 1 pregnant solution Components

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.5, controlling the temperature to be 60 ℃, controlling the concentration of iron ions in the pregnant solution to be 78.8g/L, reacting for 30min after the feed liquid is added, controlling the pH value of the solution to be 2.5 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.5 and the temperature to be 60 ℃, stirring and washing for 30min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, just dissolving the filter cake by using the added hydrochloric acid, adjusting the pH to 0.5-1.5 by using liquid alkali, heating the slurry to 70 ℃, adding sodium nitrite, adjusting the pH to be 2.5 stably by adding the liquid alkali according to 1 time of the mass of the noble metal for 30min, continuing to react for 30min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 2.1mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.1%, 100% and 95%.

Example 2

The components of a pregnant solution are shown in Table 2

TABLE 2 pregnant solution ingredients

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.6, controlling the temperature to be 75 ℃, controlling the concentration of iron ions in the pregnant solution to be 25.3g/L, reacting for 50min after the feed liquid is added, controlling the pH value of the solution to be 2.6 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.6 and the temperature to be 75 ℃, stirring and washing for 50min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, adjusting the pH value of the filter cake to 0.7 by using liquid alkali, heating the slurry to 80 ℃, adding sodium nitrite with the addition amount being 2.5 times of the mass of the noble metal, reacting for 45min, adding the liquid alkali to adjust the pH value to be 2.6, continuing to react for 50min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 5.1mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.3%, 100% and 95.5%.

Example 3

The components of a pregnant solution are shown in Table 3

TABLE 3 pregnant solution ingredients

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.7, controlling the temperature to be 85 ℃, controlling the concentration of iron ions in the pregnant solution to be 16.2g/L, reacting for 70min after the feed liquid is added, controlling the pH value of the solution to be 2.7 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.7 and the temperature to be 85 ℃, stirring and washing for 70min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, adjusting the pH value of the filter cake to 0.9 by using liquid alkali, heating the slurry to 85 ℃, adding sodium nitrite, adjusting the pH value to 2.7 by adding the liquid alkali according to 4.5 times of the mass of the noble metal, reacting for 50min, continuing to react for 60min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 1.1mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.7%, 100% and 98.5%.

Example 4

The components of a pregnant solution are shown in Table 4

TABLE 4 pregnant solution component

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.8, controlling the temperature to be 90 ℃, controlling the concentration of iron ions in the pregnant solution to be 98.8g/L, reacting for 80min after the feed liquid is added, controlling the pH value of the solution to be 2.8 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.8 and the temperature to be 90 ℃, stirring and washing for 80min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, adjusting the pH value of the filter cake to 1.0 by using liquid alkali, heating the slurry to 90 ℃, adding sodium nitrite with the addition amount being 6.5 times of the mass of the noble metal, reacting for 60min, adding the liquid alkali to adjust the pH value to be 2.8, continuing to react for 70min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 9.8mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.0%, 99.0% and 95.0%.

Example 5

The components of a pregnant solution are shown in Table 5

TABLE 5 pregnant solution ingredients

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 2.9, controlling the temperature to be 95 ℃, controlling the concentration of iron ions in the pregnant solution to be 55.0g/L, reacting for 100min after the feed liquid is added, controlling the pH value of the solution to be 2.9 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with a dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 2.9 and the temperature to be 95 ℃, stirring and washing for 100min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, adjusting the pH value of the filter cake to 1.2 by using liquid alkali, heating the slurry to 95 ℃, adding sodium nitrite, adjusting the pH value to 2.9 by adding the liquid alkali according to 8.5 times of the mass of the noble metal, reacting for 60min, continuing to react for 90min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 5.8mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.7%, 99.6% and 96.6%.

Example 6

The components of a pregnant solution are shown in Table 6

TABLE 6 pregnant solution ingredients

The method for separating iron from pregnant solution comprises the following steps:

1) hydrolysis: adding liquid caustic soda and pregnant solution into a reaction kettle simultaneously by adopting a continuous hydrolysis method, controlling the pH value of the solution to be 3.0, controlling the temperature to be 100 ℃, controlling the concentration of iron ions in the pregnant solution to be 46.7g/L, reacting for 100min after the feed liquid is added, controlling the pH value of the solution to be 3.0 all the time, and filtering after the reaction is finished to obtain a first filter cake;

2) washing: washing the first filter cake with dilute hydrochloric acid solution, controlling the pH value of the dilute hydrochloric acid solution to be 3.0 and the temperature to be 100 ℃, stirring and washing for 120min, and filtering to obtain a second filter cake;

3) and dissolving the second filter cake again by using hydrochloric acid, adjusting the pH value of the filter cake to 1.5 by using liquid alkali, heating the slurry to 100 ℃, adding sodium nitrite, adjusting the pH value to 3.0 by adding 10 times of the mass of the noble metal for 60min, adding the liquid alkali, adjusting the pH value to be 3.0, continuing to react for 120min, and filtering to obtain a third filter cake.

And analyzing the components of the third filter cake and the iron removal liquid (the filtrate and the washing liquid are integrated), wherein the concentration of iron ions in the iron removal liquid is 4.8mg/L, and the recovery rates of platinum, palladium and rhodium are respectively 99.8%, 99.6% and 97.6%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention. It should be noted that other equivalent modifications can be made by those skilled in the art in light of the teachings of the present invention, and all such modifications can be made as are within the scope of the present invention.