CN1143682A

CN1143682A - Method and digesting surface for recovering noble metals and aluminium from waste aluminium base catalyst

Info

Publication number: CN1143682A
Application number: CN95109350A
Authority: CN
Inventors: 杨茂才; 孙萼庭; 周杨霁
Original assignee: KUNMING NOBLE METAL INST CHINA NONFERROUS METAL INDUSTRY GENERAL Co
Current assignee: KUNMING NOBLE METAL INST CHINA NONFERROUS METAL INDUSTRY GENERAL Co
Priority date: 1995-08-23
Filing date: 1995-08-23
Publication date: 1997-02-26
Anticipated expiration: 2015-08-23
Also published as: CN1043250C

Abstract

A process for recovering noble metals from waste Al-base catalyst includes such technological steps as alkali digestion, water immersion for removing Al, chlorinating in aqueous solution to dissolve Pt, flocculating silica gel with animal glue, destroying animal glue with diluted sulfuric acid, displacement of Zn (or Fe) to obtain coarse Pt, refining to obtain pure Pt, and immersing dealuminization liquid in water to obtain natroalum or other aluminium salt. The digesting furnace is composed of bottom, refractory brick wall, insulating liner, movable top, kerosene blast burner as heat source and thermocouple for measuring temp..

Description

Method for recovering noble metal and aluminum from waste aluminum-based catalyst and digestion furnace

A method and a digester for recovering precious metals and aluminum from a spent aluminum-based catalyst. The present invention belongs to noble metal metallurgy.

Noble metal catalysts are widely used in the petrochemical industry and consist of a substrate and a noble metal active part. After long-term use, the active component noble metal in the catalyst is polluted by various impurities to lose activity, and becomes a waste catalyst. Noble metals are widely used, but the resources are limited, so the noble metals are expensive, and the waste materials containing the noble metals naturally become very important secondary resources. The method for recovering noble metal from the spent catalyst includes a noble metal selective dissolution method, a soluble carrier dissolution method, a dry volatilization method, a plasma smelting method, a copper smelting trapping method and the like. Patent ZL91104386.1 "method for recovering platinum from waste catalyst" (application date: 91.06.24) adopts noble metal selective dissolving method to treat T-12 waste platinum catalystThe agent provides a simple method with high platinum recovery rate and high purity, but the application is limited to a matrix insoluble catalyst, and the matrix is not recycled. The I-5 aluminum-based platinum catalyst is Al₂O₃The pellet catalyst as the matrix comprises the following main components (percent): al (Al)₂O₃96 Pt 0.36-0.37 SiO₂1.67Fe 0.37 Mn 0.11 Pb trace Ni, the diameter of the pellet is 1.5-2mm, the pellet is calcined at 1150 deg.C, and the matrix Al₂O₃The crystal form of (A) has been changed from r-type to a-type, wherein the powder accounts for about 30-40%, and most of platinum is distributed in Al in a micro-fine particle state₂O₃The middle or edge area of the matrix is coated by the matrix, belongs to a material difficult to process, and is processed by a method of selective dissolution of noble metal, so that the recovery rate of platinum is not high.

The object of the present invention is to provide a catalyst derived from Al₂O₃Recovery of platinum for any crystalline form of the spent aluminum-based catalystHigh efficiency, high purity, simple and easy operation, and can comprehensively recover aluminum, and special equipment for effectively implementing the method.

The method provided by the invention comprises the steps of alkali digestion, water leaching and dealuminization, aqueous solution chlorination and platinum dissolution, animal glue flocculation silica gel, dilute sulfate nitrate animal glue, zinc replacement (or iron replacement) to obtain crude platinum, refining the crude platinum to obtain pure platinum, and water leaching and dealuminization of aluminum liquid to prepare sodium alum Na₂AL₂(SO₄)₄·24H₂O]The method comprises the following specific steps: (1) mixing the waste catalyst and sodium hydroxide, wherein the dosage of the waste catalyst and the sodium hydroxide (weight ratio) is 1: 1-3, preferably 1: 1-1.2, and carrying out alkali digestion reaction in a designed and manufactured digestion furnace at the temperature of 500-: ， (ii) a (2) Leaching alkaline digestion residue with water at boiling temperature for 5-30 min, wherein the ratio of alkaline digestion residue weight gram to water volume milliliter is 1: 5-12, preferably 1: 5-10,the aluminum removal rate is more than or equal to 98 percent, and the platinum contained in the water immersion aluminum removal liquid is less than 0.0005 g/L; (3) dissolving water-soaked residues in 3-6mol of HCl medium at a temperature of 80-85 ℃ for 1 time, wherein the ratio of weight grams of the residues to volume milliliters of HCl solution is about 1: 4, activating platinum by alkali digestion, dissolving most of the platinum in HCl for 1-2 hours, extracting supernatant, adding sodium chlorate oxidant into the residues under the conditions of the same concentration of HCl medium, dosage ratio and temperature, wherein the addition amount of the sodium chlorate oxidant is 10% of the weight of the residues, and the time is 1-2 hours, and dissolving again; (4) mixing the platinum solutions, adding 5-10% gelatin solution (volume ratio of gelatin solution to feed solution of 1: 10000-25: 1000) at room temperature, stirring slowly to flocculate silica gel, filtering to remove silica gel and platinum-dissolving residue, and adding into the solution2-3% concentrated sulfuric acid at 90-100 deg.C, and breaking animal glue for 20-30 min; (5) gradually adding zinc powder (or iron powder) into the solution obtained in the step (4) at normal temperature for replacement to obtain crude platinum precipitate, filtering, dissolving the crude platinum once again by a aqua regia dissolving method or a sodium chlorate oxidation aqueous solution chlorination method, hydrolyzing by sodium bromate, hydrolyzing by a carrier, precipitating platinum by ammonium chloride, and calcining to obtain pure sponge platinum powder refined by a traditional refining method; (6) adding sulfuric acid into the water leaching dealumination solution for reaction, evaporating the obtained solution to obtain sodium alum [ Na]₂AL₂(SO₄)₄·24H₂O]And (4) crystallizing.

In order to realize high implementation efficiency of the method, the alkali digestion furnace is designed and manufactured, and is now described with reference to the attached drawings, wherein fig. 1 is a schematic view of a digestion furnace (I), a1 is a front view, b1 is a side view, C1 is a top view, 1, a furnace top steel frame, 2, a furnace top heat-insulating brick, 3, a hanging ring, 4, a furnace wall, 5, an inner lining heat-insulating layer, 6, a heat source fire spraying hole, 7 and a thermocouple. FIG. 2 is a schematic view showing the charging of a digester (I),A is a schematic view showing the charging of a bottom tray, B2-5 layers are schematic views showing the charging of a digester, C is a schematic view showing arrangement of refractory brick pads, 8 is a refractory brick pad, 9 is a flame path of a hearth, FIG. 3 is a schematic view showing the charging of a digester (II), a2 is a front view, B2 is a side view, and C2 is a top view, and (1), (2), (3), (4), (5), (6), (7) are the same as those in FIG. 1 and (10) are fire-blocking bricks.

The designed and manufactured digestion furnace consists of furnace bottoms (8, 9), a furnace wall (4), an inner lining heat-insulating layer (5), furnace tops (1, 2, 3), a heat source (6) and a thermocouple (7), and is in a cuboid shape, and is characterized in that the furnace bottom is provided with a cross-shaped flame channel (9), furnace bottom refractory brick cushion blocks (8) are laid above the channel, and the cushion blocks are arranged above and around the flame channel and are spaced from each other; the furnace wall (4) is built by refractory bricks, and a light insulating brick layer (5) is built in the furnace wall; the furnace top is movable and is formed by alternately stacking a steel frame (1) with a lifting ring (3) and 2 or 3 layers of light heat-insulating bricks in the steel frame; kerosene blowtorch is used as heat source, and the lower part of the furnace is simultaneously sprayed into the furnace from the four-side flame spraying holes (6), and the flame flowing direction is adjusted by the fire blocking bricks (10) and the material tray for fire isolation and the coordination with the flame channel at the bottom of the furnace. The digestion furnace with the structure has high heating speed, good heat preservation performance and energy consumption saving; the movable furnace top structure is convenient for hoisting and placing, is convenient for charging and discharging, ensures that the furnace top has uniform air permeability and enough heat preservation, is favorable for volatilization of combustion waste gas and water vapor of reaction products and flame diffusion, can ensure that the upper area of the furnace reaches the temperature required by reaction, and can also be provided with a material drying steel disc above the furnace top to bake wet materials by utilizing waste heat; the material in the furnace can fill the whole furnace chamber, so the processing capacity of the equipment is high; the size of the furnace body can be adjusted according to the production scale, the adaptability is strong, the material tray can be made of materials such as burning-resistant cast iron, steel plates, stainless steel plates and the like, and can bear the corrosion of caustic alkali at the temperature of 800 ℃; the operation atmosphere is good, and a separate ventilation and dust collection system is not required to be established.

The invention has the advantages that: 1. the recovery rate of platinum is greater than or equal to 97%, the purity is as high as 99.95% -99.99%, the method can be directly used for manufacturing the new catalyst 2, the method is simple and easy to implement, 3, aluminum can be comprehensively recovered, 4, the structure of the digestion furnace is reasonable, the operation is stable and reliable, the energy consumption is low, and the environment is not polluted.

Examples

Two kinds of digestion furnaces are built by using refractory bricks, light insulating bricks, steel, a blast lamp and a thermocouple according to the structural design in the specification:

the effective size of the furnace of the digestion furnace (I) is 1400 multiplied by 1100 multiplied by 1000mm, each furnace can be provided with 104 small material trays with the size of 290 multiplied by 220multiplied by 140mm, the material is charged with 800 multiplied by 880Kg, 8 kerosene blowlamps are used for blasting fire, the heating and digestion time is 6 to 7 hours per furnace, the coal oil consumption is 70Kg per furnace, the primary water leaching and dealuminization rate is 88 to 92 percent, the noble metal platinum is enriched by 8.3 to 12.5 times, and the platinum content of the water leaching dealuminization liquid is less than 0.0005 g/l (the same below). The effective size of the furnace of the digestion furnace (II) is 1100 multiplied by 900mm, each furnace is provided with 6 large charging trays with the size of 900 multiplied by 430 multiplied by 420mm, the furnace is charged with 400 plus materials/furnace, 4 blowlamps are used for blasting fire, the heating and digestion time is 3 to 3.5 hours/furnace, the coal consumption oil is 25 Kg/furnace, the cumulative dealuminization rate of the secondary digestion water is 98 to 98.5 percent, and the platinum enrichment is 50 to 66.6 times.

Example 1 pellet-shaped spent aluminum-based platinum catalyst 1000g, content of a-Al₂O₃96.5 percent of Pt 3650g/t, (1) carrying out alkaline digestion reaction for 1.5 hours at the temperature of 700 ℃ under the condition that the weight ratio of the waste catalyst to the sodium hydroxide is 1: 1; (2) leaching alkali to eliminate slag with water in the weight ratio of slag to water volume of 1 to 5 at boiling temperature for 6 min and aluminum eliminating rate of 98%; (3) placing the water leaching slag in a 6N HCl medium, wherein the ratio of the weight gram of the slag to the volume milliliter of the HCl solution is 1: 4, and adding sodium chlorate with the weight of 10 percent of the slag as an oxidant to chloridize and dissolve platinum; (4) gradually adding zinc powder into the platinum solution at normal temperature to replace crude platinum, filtering the crude platinum powder, dissolving the crude platinum powder for 1 time by the method (3), hydrolyzing the platinum solution obtained in the step (5) and the step (4) by sodium bromate, hydrolyzing a carrier, hydrolyzing ammonium chloride to precipitate platinum, and calcining by the traditional refining method to obtain 3.563g of spongy platinum, wherein the purity is 99.95 percent, and the recovery rate is 97.6 percent; (6) adding industrial sulfuric acid into the water leaching dealuminization solution for reaction, and evaporating the solution to obtain sodium alum crystals Na₂AL₂(SO₄)₄·24H₂O]And recovering the aluminum.

Example 2 pellet-shaped waste aluminum-based platinum catalyst 10g containing r-Al₂O₃96.5 percent, and the Pt 4000g/t (1) is subjected to alkali digestion for 1 hour under the conditions that the waste catalyst and the sodium hydroxide are 1: 2.82 and the temperature is 800 ℃; (2) the conditions of water leaching dealumination are the same as example 1, the aluminum removal rate is 98.50%, platinum concentrate is produced, the grade is 26.6%, the weight is 0.15g, the platinum is enriched by 66.5 times, and the recovery rate is more than 99%.

EXAMPLE 3 Small spherical spent aluminum-based platinum catalystReagent 902.2g, 2Al₂O₃96.5 percent of Pt 897g/t, (1) carrying out alkali digestion for 2 hours under the conditions that the ratio of waste to sodium hydroxide is 1: 1 and the temperature is 600 ℃, and (2) carrying out water leaching dealumination under the same conditions as example 1, wherein the aluminum removal rate is 98 percent, platinum concentrate is produced, the grade is 5.93 percent, the weight is 13.65g, the platinum is enriched by 66 times, and the recovery rate is more than 99 percent.

Example 4 pellet-shaped spent alumina-based platinum catalyst 300Kg containing a-Al₂O₃96.5% and 0.36% of Pt, (1) mixing the waste catalyst withsodium hydroxide, reacting the waste material and the sodium hydroxide for 6 hours in a designed and manufactured alkali digestion furnace (I) at the temperature of 800 ℃, and (2) leaching alkali digestion slag by water, wherein the ratio of the weight kilogram of the slag to the volume liter of the water is 1: 10, and the temperature: boiling water at the temperature of 30 minutes, wherein the leaching rate of aluminum is 92 percent, the leaching solution contains platinum less than 0.0005 g/L, (3) leaching water slag of 24Kg (containing Pt 4.48 percent), dissolving platinum once at the temperature of 85 ℃ under the condition that the ratio of the weight kilogram of the slag to the volume liter of hydrochloric acid is 1: 4 in 3mol of HCl medium (platinum is activated by alkaline digestion and HCl is soluble), extracting supernatant, dissolving the slag for 1 time by using dilute aqua regia (concentrated nitric acid: concentrated hydrochloric acid is 1: 3, and adding water for diluting for 1 time), converting the aqua regia dissolving solution into hydrochloric acid medium, combining the hydrochloric acid medium with the 1 st HCl dissolving solution, adding 5 percent animal glue solution at normal temperature, stirring the glue solution and the feed solution (volume ratio) of 25: 1000, filtering after flocculating silica gel, washing slag, obtaining 18Kg of platinum-dissolved residue (containing Pt 0.116 percent), and the platinum rate of 98.07 percent; returning the platinum-dissolved residue to the digestion process to recover platinum again.

The invention is not only suitable for recovering platinum and aluminum from the aluminum-based platinum-containing catalyst, but also suitable for recovering noble metal and aluminum from the aluminum-based platinum-containing catalyst, palladium-containing catalyst and rhodium-containing catalyst.

Claims

1. A process for recovering noble metal and Al from waste Al-base catalyst includes alkali digestion, water immersion for removing Al, dissolving Pt in aqueous solution by chlorination, flocculating animal gum, breaking animal gum by diluted sulfuric acid, zinc displacement (or iron displacement), refining coarse Pt, preparing Na alum₂AL₂(SO₄)₄·24H₂O]The method comprises the following steps:

1.1 alkaline digestion conditions were: mixing the waste catalyst with alkali, wherein the alkali is sodium hydroxide, the dosage of the alkali is that the weight ratio of the waste catalyst to the sodium hydroxide is 1: 1-3, the temperature is 500-;

1.2 the water immersion dealumination conditions are as follows: leaching aluminum salt from the alkaline digestion residue with water to remove aluminum, wherein the ratio of the weight gram of the alkaline digestion residue to the volume milliliter of the water is 1: 5-12, the temperature is the boiling temperature of the water, and the time is 5-30 minutes;

1.3 conditions for chloridizing and dissolving platinum in aqueous solution are as follows: dissolving the water leached aluminum-removed slag in 3-6mol HCl medium at a ratio of weight gram of slag to volume milliliter of HCl solution of about 1: 4 at 80-85 ℃ for 1-2 hours, extracting supernatant, adding sodium chlorate oxidant into the residual slag under the conditions of HCl medium with the same concentration, dosage ratio and temperature, dissolving for 1-2 hours, wherein the addition amount of the sodium chlorate oxidant is 10% of the weight of the residual slag;

1.4 flocculating the silica gel with the conditions for destroying the gelatin by dilute sulfuric acid are as follows: adding 5-10% animal gelatin solution into platinum solution at room temperature, stirring slowly to flocculate silica gel, filtering, adding 2-3% concentrated sulfuric acid into the solution at 90-100 deg.C for 20-30 min;

1.5 zinc displacement or iron displacement to obtain crude platinum → the refining method of the crude platinum is as follows: adding zinc powder (or iron powder) into the solution obtained in step 1.4 at normal temperature, gradually replacing to obtain crude platinum precipitate, dissolving the crude platinum after filtering by aqua regia or sodium chlorate oxidation aqueous solution chlorination method, hydrolyzing with sodium bromate, hydrolyzing with carrier, precipitating platinum with ammonium chloride, and calcining to obtain pure sponge platinum powder refined platinum by traditional refining method;

1.6 the method for preparing the sodium alum by leaching the molten aluminum by water comprises the following steps: adding sulfuric acid into the water leaching dealumination solution for reaction, evaporating the obtained solution to obtain sodium alum [ Na]₂AL₂(SO₄)₄·24H₂O]And (4) crystallizing.

2. The method for recovering noble metals and aluminum from a waste aluminum-based catalyst according to claim 1, wherein:

2.1 the alkaline digestion conditions are: mixing the waste catalyst and sodium hydroxide, wherein the consumption of the waste catalyst and the sodium hydroxide is 1: 1-1.2 (weight ratio), the temperature is 600-;

2.2 the water leaching dealumination conditions are as follows: the alkaline digestion residue is subjected to dealuminization by leaching aluminum salt with water, wherein the dosage of the aluminum salt is that the ratio of the weight gram of the alkaline digestion residue to the volume milliliter of water is 1: 5-10, the temperature is the boiling temperature of the water, and the time is 5-30 minutes.

3. The digester as claimed in claim 1, which is comprised of a bottom (8, 9), walls (4), an insulating layer (5) of lining, tops (1, 2, 3), a heat source (6), and a thermocouple (7) for measuring temperature, and is a cuboid, characterized in that the bottom has a cross-shaped flame channel (9), and a bottom refractory brick pad (8) is laid above the channel, and the pads are arranged along the upper and peripheral sides of the flame channel with a space therebetween; the furnace wall is built by refractory bricks, and a light insulating brick layer is built in the furnace wall; the furnace top is movable and is formed by stacking a steel frame (1) with a hanging ring (3) and 2 or 3 layers of light heat-insulating bricks (2) in the steel frame in a crossed manner; kerosene blowtorch is used as heat source (6), and the lower part of the furnace is simultaneously sprayed into the furnace from the four-side flame spraying holes, and flame flowing direction is adjusted by the fire blocking bricks (10) and the material tray fire isolation and the coordination with the flame channel at the bottom of the furnace.