CN108411122B - Flux and alkaline flux for recovering ruthenium from supported ruthenium catalyst waste and method for recovering ruthenium - Google Patents

Abstract

The invention discloses a flux for recovering ruthenium from a waste of a supported ruthenium _- based catalyst and a method for recovering an alkaline _flux and ruthenium _. It is composed according to the weight ratio of 0‑1:1. The basic flux is composed of the following components according to weight percentage: basic molten salt 50%-70%, peroxide 16%-26%, K ₂ SiF ₆ 0-16%, KAlF ₄ 8%-16%. It can reduce the melting temperature of the supported ruthenium-based catalyst waste, improve the fluidity of the supported ruthenium-based catalyst waste in the alkali melting system, reduce energy consumption, improve the recovery efficiency of ruthenium, and save the recovery of ruthenium from the supported ruthenium-based catalyst waste. the cost of.

Description

Recovery of Ruthenium Flux, Basic Flux and Ruthenium from Supported Ruthenium-based Catalyst Waste method of recycling

technical field

The present invention relates to a flux for recovering ruthenium from wastes of supported ruthenium-based catalysts, a basic flux for recovering ruthenium from wastes of supported ruthenium-based catalysts, and a method for recovering ruthenium.

Background technique

Ruthenium, one of the platinum group metals, is found in small amounts (one part in a billion) in the earth's crust and is the rarest precious metal. my country's ruthenium resources are scarce, and almost all rely on imports (accounting for 99% of the total demand). Therefore, it is necessary to recover and reuse ruthenium containing ruthenium and ruthenium-based compounds. Ruthenium and ruthenium-based compounds have stable chemical properties and strong corrosion resistance. They cannot be dissolved in hydrochloric acid, sulfuric acid, nitric acid and aqua regia at room temperature, while the ruthenium in the supported ruthenium-based catalyst is closely attached to the surface or cavities of the carrier. very difficult. In the recycling process of ruthenium, the main method currently used is the alkali fusion method, and the general method is to put the ruthenium-containing waste into the peroxide of the alkali molten salt to carry out high temperature alkali fusion (the temperature is about 750 degrees Celsius), Then, oxidative distillation is carried out to collect in an acidic or basic solution and reduce to soluble ruthenium or a ruthenium-based compound. In the whole recycling process, high temperature melting is required (about 750 degrees Celsius, when the alkali melting temperature is low, the melting time is as long as 600 minutes), and the energy consumption is high. In addition, in order to improve the recovery rate of ruthenium, it is necessary to carry out long-term melting or multiple recovery under high temperature conditions, which consumes a lot of energy and basic flux, which is not conducive to the recovery and utilization of ruthenium in the supported ruthenium-based catalyst waste.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the first object of the present invention is to provide a flux for recovering ruthenium from the waste of supported ruthenium-based catalysts, and the second object of the present invention is to provide a kind of recovery of ruthenium from waste of supported ruthenium-based catalysts The basic flux, the third purpose is to provide a method for recovering ruthenium in the waste of a supported ruthenium-based catalyst.

In order to achieve the above-mentioned first purpose, the technical scheme of the present invention is: a flux for recovering ruthenium from a supported ruthenium-based catalyst waste, characterized in that: by K ₂ SiF ₆ and KAlF ₄ in a weight ratio of 0-1:1 composition.

Preferably: the weight ratio of K ₂ SiF ₆ to KAlF ₄ is 1:1. Since the compounds of K ₂ SiF ₆ and _{KAlF 4} are similar in composition, a eutectic system is formed, the melting point of _{KAlF 4} is lowered, and the eutectic temperature of the molten salt will also decrease accordingly _. The liquidus temperature of the molten salt gradually decreases. When the weight ratio of K ₂ SiF ₆ to KAlF ₄ is 1:1, the eutectic temperature of the molten salt system will no longer decrease, so that the melting time can be controlled within 60 min, and the recovery rate is greater than 99 %, increase the melting speed and reduce energy consumption.

In order to achieve the above-mentioned second purpose, the technical scheme of the present invention is: an alkaline flux for recovering ruthenium from a supported ruthenium-based catalyst waste, which is characterized in that: it is composed of the following components according to weight percentage: alkaline molten salt 50%～ 70%, peroxide 16% to 26%, K ₂ SiF ₆ 0 to 16%, KAlF ₄ 8% to 16%.

Preferably: the weight ratio of the K ₂ SiF ₆ and KAlF ₄ is 1:1.

Using the above scheme, KAlF ₄ has low viscosity, low surface tension, high fluidity, and still exists in the molecular state in the liquid state, has superfluid properties, and improves the fluidity, mass transfer and transfer of ruthenium waste in the alkali melting system. Thermal efficiency is significantly improved. The mixing of KAlF ₄ with alkaline molten salt and peroxide reduces the eutectic point of the system, while the molecular formula of K ₂ SiF ₆ is close to that of KAlF _4. After adding, it can increase the solubility in the eutectic melt and promote the melting. Therefore, the entire quaternary system exhibits a decrease in the eutectic temperature. The basic flux obtained by the invention can reduce the melting temperature by 120°C to 197°C, has low energy consumption, short melting time and high recovery rate.

In the above scheme: the alkaline molten salt is an alkali metal hydroxide or an alkaline earth metal hydroxide or an alkali metal carbonate or an alkaline earth metal carbonate.

In the above scheme: the peroxide is an alkali metal peroxide or an alkaline earth metal peroxide.

In the above scheme: it is composed of the following components according to weight percentage: KOH 60%, K ₂ O ₂ 20%, K ₂ SiF ₆ 10%, KAlF ₄ 10%. By using the alkaline flux with the percentage and composition, the melting temperature can be reduced to 553 degrees Celsius, which is the most reduced compared with the corresponding binary alkaline flux.

In order to achieve the above-mentioned third object, the technical scheme of the present invention is: a method for recovering ruthenium from a supported ruthenium-based catalyst waste, which is characterized in that: comprising placing the supported ruthenium-based catalyst waste in a reactor, adding the above-mentioned alkaline The flux is then heated to 553-630 °C for the melting step.

Preferably: the mass of the basic flux is 25-35 times the mass of the supported ruthenium-based catalyst waste.

Beneficial effect: using the flux of the present invention, when obtaining the same recovery rate of ruthenium (90% to 99%), the melting temperature of the composite alkaline flux is higher than that of the binary alkaline flux (made of alkaline molten salt and The peroxide composition) is lowered by 120°C to 197°C, thereby reducing energy consumption and reducing the recovery cost of ruthenium in the waste of the supported ruthenium-based catalyst.

Detailed ways

Below in conjunction with embodiment, the present invention is further described:

Example 1

_Weigh the loaded ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times of the amount of the waste. K ₂ SiF ₆ 10%, KAlF ₄ 10%, the temperature is raised to 553° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%. And adopt binary basic flux with composition of KOH 75%, K ₂ O ₂ 25% (remove K ₂ SiF ₆ and KAlF ₄ ,), heat up to 553° C., hold time 60min, the recovery of ruthenium in the supported ruthenium-based catalyst waste The rate is 76%. If the temperature is raised to 750°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%. The energy consumption is much higher than the basic flux of the present invention.

Example 2

Weigh the load _- type ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times the amount of the waste. K ₂ SiF ₆ 12%, KAlF ₄ 12%, the temperature is raised to 580° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%. Using binary alkaline flux with the composition of KOH 76% and K ₂ O ₂ 24%, the temperature was raised to 580° C. and the holding time was 60 min. The recovery rate of ruthenium in the supported ruthenium-based catalyst waste was 78%. If the temperature is raised to 750°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 3

_Weigh the loaded ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times of the amount of the waste. K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature is raised to 590° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste can reach more than 99%. Using a binary alkaline flux with a composition of 75% KOH and 25% K ₂ O ₂ , the temperature was raised to 590° C. and the holding time was 60 min. The recovery rate of ruthenium in the supported ruthenium-based catalyst waste was 79%. If the temperature is raised to 750°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 4

Weigh the load-type ruthenium-based catalyst waste in the reactor, add composite alkaline flux according to 30 times the amount of the waste, and the weight ratio of the components of the composite alkaline flux is: NaOH 60%, Na ₂ O ₂ 20%, K ₂ SiF ₆ 10%, KAlF ₄ 10%, the temperature is raised to 587° C., and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%. Using binary alkaline flux with the composition of NaOH 75% and Na ₂ O ₂ 25%, the temperature was raised to 587° C. and the holding time was 60 min. The recovery rate of ruthenium in the supported ruthenium-based catalyst waste was 74%. If the temperature is raised to 760°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 5

Weigh the load-type ruthenium-based catalyst waste in the reactor, add a composite alkaline flux according to 30 times the amount of the waste, and the component formula weight ratio of the composite alkaline flux is: NaOH 58%, Na ₂ O ₂ 18%, K ₂ SiF ₆ 12%, KAlF ₄ 12%, the temperature is raised to 605° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%. However, using binary alkaline flux consisting of NaOH 76% and Na ₂ O ₂ 24%, heating to 605° C. for 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste is only 77%. If the temperature is raised to 760°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 6

Weigh a certain amount of load-type ruthenium-based catalyst waste in the reactor, add a composite alkaline flux by 30 times the amount of the waste, and the component formula weight ratio of the composite alkaline flux is: NaOH 63%, Na ₂ O ₂ 21%, K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature was raised to 618 ° C and the holding time was 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reached more than 99%; and the composition was NaOH 75% , Na ₂ O ₂ 25% binary alkaline flux, the temperature was raised to 618° C., the holding time was 60 min, and the recovery rate of ruthenium in the supported ruthenium-based catalyst waste was 78%. If the temperature is raised to 760°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 7

Weigh the load-type ruthenium-based catalyst waste in the reactor, add a composite alkaline flux according to 30 times the amount of the waste, and the composition weight ratio of the composite alkaline flux is: Na ₂ CO ₃ 63%, BaO ₂ 21%, K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature was raised to 620° C., and the holding time was 60 min. The recovery rate of ruthenium in the supported ruthenium-based catalyst waste reached more than 99%. However, using a binary alkaline flux with a composition of Na ₂ CO ₃ 75% and BaO ₂ 25%, heating to 620° C. for 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste is only 70%. If the temperature is raised to 780°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 8

Weigh the loaded ruthenium-based catalyst waste in the reactor, add a composite alkaline flux according to 30 times the amount of the waste, and the composition weight ratio of the composite alkaline flux is: Ca(OH) ₂ 63%, BaO ₂ 21%, K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature was raised to 622° C., and the holding time was 60 min. The recovery rate of ruthenium in the supported ruthenium-based catalyst waste reached more than 99%. However, using a binary alkaline flux with a composition of Ca(OH) ₂ 75% and BaO ₂ 25%, heating to 620° C. for 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste is only 72%. If the temperature is raised to 780°C and the holding time is 60min, the recovery rate of ruthenium can reach 99%.

Example 9

Weigh the load-type ruthenium-based catalyst waste in the reactor, and add composite basic flux according to 30 times the amount of the waste. The composition weight ratio of the composite basic flux is: K ₂ CO ₃ 63%, BaO ₂ 21%, K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature was raised to 619° C. and the holding time was 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reached more than 99%. On the other hand, using a binary alkaline flux with a composition of CaCO ₃ 75% and BaO ₂ 25%, heating to 619° C. and holding for 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste is only 73%. If the temperature is raised to 780°C and the holding time is 60min, the recovery rate of ruthenium can reach more than 99%.

Example 10

_Weigh the loaded ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times of the amount of the waste. KAlF ₄ was 10%, the temperature was raised to 630° C., and the recovery rate of ruthenium in the supported ruthenium-based catalyst waste was maintained for 60 minutes to reach 99%.

Example 11

_Weigh the loaded ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times the amount of the waste. K ₂ SiF ₆ 8%, KAlF ₄ 10%, the temperature was raised to 607° C., and the recovery rate of ruthenium in the supported ruthenium-based catalyst waste was maintained for 60 min to reach 99%.

Example 12

_Weigh the loaded ruthenium _- based catalyst waste in the reactor, and add composite alkaline flux according to 30 times the amount of the waste. K ₂ SiF ₆ 1%, KAlF ₄ 10%, the temperature was raised to 618° C., and the recovery rate of ruthenium in the supported ruthenium-based catalyst waste was maintained for 60 min to reach 99%.

Example 13

Weigh the load-type ruthenium-based catalyst waste in the reactor, add the composite alkaline flux according to 35 times the weight of the waste, and the composition weight ratio of the composite alkaline flux is: KOH 60%, K ₂ O ₂ 20%, K ₂ SiF ₆ 10%, KAlF ₄ 10%, the temperature is raised to 553° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%.

Example 14

Weigh the load _- type ruthenium _- based catalyst waste in the reactor, add the composite alkaline flux according to 25 times the amount of the waste. K ₂ SiF ₆ 10%, KAlF ₄ 10%, the temperature is raised to 553° C. and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%.

Example 15

Weigh the load-type ruthenium-based catalyst waste in the reactor, add the composite alkaline flux according to 25 times the weight of the waste, and the composition weight ratio of the composite alkaline flux is: KOH 50%, K ₂ O ₂ 18%, K ₂ SiF ₆ 16%, KAlF ₄ 16%, the temperature is raised to 602° C., and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%.

Example 16

Weigh the load _- type ruthenium _- based catalyst waste in the reactor, add the composite alkaline flux according to 25 times the amount of the waste. K ₂ SiF ₆ 8%, KAlF ₄ 8%, the temperature was raised to 593° C., and the holding time was 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reached more than 99%.

Example 17

Weigh the load-type ruthenium-based catalyst waste in the reactor, add the composite alkaline flux according to 25 times the weight of the waste, and the composition weight ratio of the composite alkaline flux is: KOH 50%, K ₂ O ₂ 26%, K ₂ SiF ₆ 12%, KAlF ₄ 12%, the temperature is raised to 587° C., and the holding time is 60 min, the recovery rate of ruthenium in the supported ruthenium-based catalyst waste reaches more than 99%.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (5)

1. A method for recovering ruthenium from a supported ruthenium catalyst waste is characterized by comprising the following steps: the method comprises the steps of putting a supported ruthenium catalyst waste into a reactor, adding an alkaline flux, and heating to 553-630 ℃ for melting, wherein the alkaline flux comprises the following components in percentage by weight: 50-70% of alkaline molten salt, 16-26% of peroxide and K ₂SiF ₆0～16%、KAlF ₄8% -16%, the K ₂SiF ₆And KAlF ₄In a weight ratio of 1: 1.

2. The method for recovering ruthenium from the waste supported ruthenium catalyst according to claim 1, wherein the method comprises the following steps: the alkaline molten salt is alkali metal hydroxide or alkaline earth metal hydroxide or alkali metal carbonate or alkaline earth metal carbonate.

3. The method for recovering ruthenium from the waste supported ruthenium catalyst according to claim 1 or 2, wherein: the peroxide is an alkali metal peroxide or an alkaline earth metal peroxide.

4. The method for recovering ruthenium from the waste supported ruthenium catalyst according to claim 3, wherein the method comprises the following steps: the composition comprises the following components in percentage by weight: KOH 60%, K ₂O ₂20%、K ₂SiF ₆10%、KAlF ₄10%。

5. The method for recovering ruthenium from the waste supported ruthenium catalyst according to claim 4, wherein: the mass of the alkaline flux is 25-35 times of that of the supported ruthenium catalyst waste.