Method for co-processing lead glass and waste catalyst
Technical Field
The invention relates to the technical field of solid waste treatment, in particular to a method for the cooperative treatment of lead glass and a waste catalyst.
Background
The automobile exhaust catalyst mainly plays a role in converting CO and CH in automobile exhaustxAnd NOxConversion to non-toxic CO2、H2O and N2. Currently, the catalyst most widely used in automobiles is a catalyst using cordierite as a carrier, and platinum group metal particles are coated on the surface of the carrier. During the long-term use of the catalyst, the platinum group metal loses its catalytic activity due to contamination and encapsulation by impurities, and becomes a spent catalyst. A large amount of waste automobile catalysts are generated in China every year and are important platinum group metal secondary resources. At present, the methods for recovering platinum group metals from waste automobile catalysts mainly comprise pyrometallurgical method, wet method and combined fire-wet method. Among the pyrometallurgical processes, there are plasma smelting, metal trapping, pyrogenic chlorination, high temperature volatilization and incineration. Because of the high melting point of the catalyst, high temperature heating is usually required during the pyrogenic process, and large amounts of fluxing agents and collectors need to be added. The slag phase after smelting contains a large amount of sensible heat, the prior art mostly only focuses on the recovery of platinum group metals, and the utilization of the molten slag phase is neglected. For example, patent document No. 201810185054.8 discloses a "method for recovering noble metal platinum from automobile waste catalyst by fire method", which comprises melting with an iron-containing oxide as a collector in a DC arc furnace at a high temperature of 1600-2000 deg.C, naturally cooling the upper slag liquid at room temperature to form a glass state or forming a glass by water quenchingThe beads, which have high energy consumption for smelting, do not effectively recover the slag.
Disclosure of Invention
Aiming at the problems in the prior art, the invention mainly aims to provide a method for the cooperative disposal of lead glass and a waste catalyst, which is used for extracting platinum group metals in the waste automobile catalyst, and simultaneously preparing lead-containing glass and other components of the waste automobile catalyst into microcrystalline glass with high added value, so as to realize the harmless and high-value recovery of the lead glass and the waste automobile catalyst.
In order to solve the technical problems, the invention adopts the technical scheme that: a method for the cooperative disposal of lead glass and a waste catalyst comprises the following steps:
s1: crushing lead glass and a waste catalyst to 0.074-0.178 mm; lead glass, waste catalyst, calcium oxide and reducer anthracite are uniformly mixed, and are put into a graphite crucible after being agglomerated; placing the graphite crucible in a high-temperature furnace, smelting at 1300-1500 ℃, and simultaneously blowing argon above the melt;
s2: after smelting, performing water quenching on the upper layer glass melt to obtain basic glass particles, and separating the lower layer metal melt after cooling in the air to obtain lead alloy;
s3: and drying, fine grinding and sintering the basic glass particles to obtain the glass ceramics.
As a preferred embodiment of the present invention, the lead glass is waste cathode ray tube cone glass, and the chemical composition of the lead glass by mass percentage is as follows: 20-25% of PbO and SiO240-55%、K2O 4-9%、Na2O 3-6%、CaO 1-5%、Al2O32-6%。
As a preferred embodiment of the present invention, the waste catalyst is a waste automobile three-way catalyst, and the chemical composition of the waste automobile three-way catalyst is as follows: MgO 8-13 wt%, SiO235-50% of Al in percentage by mass2O3The mass percentage content is 25-40%, the Pt content is 300-700g/t, the Pd content is 800-1400g/t, and the Rh content is 100-300 g/t.
In a preferred embodiment of the invention, when the lead glass, the waste catalyst, the calcium oxide and the anthracite are mixed, the mass ratio of the lead glass to the waste catalyst is (1-1.5):1, the mass of the calcium oxide is 15-30% of the total mass of the lead glass and the waste catalyst, and the addition amount of the anthracite is 2-3% of the mass of the lead glass.
In a preferred embodiment of the present invention, the high temperature furnace is a medium frequency induction furnace.
In a preferred embodiment of the present invention, the flow rate of the argon gas to be blown is 0.4 to 0.8 L.min-1。
As a preferred embodiment of the present invention, SiO in the base glass particles is obtained240-60% of CaO, 14-23% of Al2O3The content is 13-20%.
As a preferred embodiment of the invention, the total content of platinum, palladium and rhodium in the lead alloy is 0.5-1.0%, and the comprehensive recovery rate of platinum, palladium and rhodium is more than or equal to 98%.
As a preferred embodiment of the present invention, in step S3, the sintering process includes: heating the finely ground basic glass particles to 950 ℃ and 1150 ℃ at the heating rate of 5-10 ℃/min, preserving the heat for 1-3h, and cooling along with the furnace to obtain the microcrystalline glass, wherein the lead content in the microcrystalline glass is less than or equal to 0.8%.
The other raw material lead glass in the invention is waste cathode ray tube cone glass, and the chemical composition of the lead glass in percentage by mass is as follows: 20-25% of PbO and SiO240-55%、K2O 4-9%、Na2O 3-6%、CaO 1-5%、Al2O32 to 6 percent. Lead-containing glass has good electrical properties and can absorb harmful rays, and therefore is used for producing Cathode Ray Tubes (CRT) for televisions and displays. With the rapid development of display technology, the conventional CRT display is gradually replaced by advanced one, resulting in a large number of CRT displays entering the scrapping stage. More than 30% of CRT glass is lead-containing glass containing about 20-25% of PbO and 40-55% of SiO24-9% of K2O and 3-6% of Na2O, and the like. Lead is a good collector of platinum group metals and is easy to separate, and the use of lead-containing glass as a waste automotive catalyst can achieve efficient extraction of platinum group metalsAnd the dosage of the auxiliary additive is reduced.
Specifically, the principle of the present invention for disposing lead glass in cooperation with a waste automobile catalyst is as follows. The lead is subjected to carbothermic reduction at high temperature to produce metallic lead, the lead glass is mixed with the waste automobile catalyst, metallic lead particles produced by the lead glass at high temperature can react with platinum group metals to generate alloys, and the platinum group metals are captured. Lead exists in the glass in the form of lead silicate, the reduction rate is lower than that of lead oxide, so that the metal lead stays in the melt for a longer time, and the trapping efficiency of the platinum group metal is ensured. Smelting in an induction furnace to generate electromagnetic stirring, promoting the contact of metal lead particles and platinum group metals to ensure more sufficient reaction, introducing argon to generate stirring, and further strengthening the trapping effect. Lead glass contains a large amount of low melting point K2O and Na2And O, the melting point of the waste automobile catalyst can be greatly reduced, the viscosity of the melt is reduced, the fluidity of the glass melt is improved, and the trapping is promoted. After the lead catches platinum group metals, the lead is continuously gathered and grows up and finally settles to the bottom of the crucible. The upper metal layer is glass melt and mainly contains SiO2CaO and Al2O3Is the main component of the microcrystalline glass. Lead glass provides the SiO required by microcrystalline glass2While lead glass contains K2O and Na2O, the crystallization performance of the microcrystalline glass can be improved, the crystallization activation energy is improved, and sintering is promoted; SiO required by microcrystalline glass provided by waste automobile catalyst2、Al2O3Containing ZrO at the same time2、Fe2O3Is a good nucleating agent and can promote the crystallization of the microcrystalline glass. And pouring the glass melt into water to form base glass particles, and sintering the base glass at the temperature close to the crystallization temperature to obtain the microcrystalline glass product.
The invention has the following beneficial effects:
(1) the cheap and easily-obtained waste lead-containing glass is used as a trapping agent, platinum group metals in the waste automobile catalyst are efficiently recovered, the using amount of auxiliary additives and the trapping agent is reduced, the waste is treated by waste, the produced lead alloy can be separated from the lead product and the platinum group metals in a vacuum volatilization mode, and the production cost is reduced.
(2) Lead in the lead glass exists in the form of lead silicate, the retention time of the lead in a melt is long during smelting, and the platinum group metal trapping efficiency is high.
(3) The lead-containing glass is used as the trapping agent, so that the melting point and viscosity of the waste automobile catalyst can be reduced, the energy consumption is reduced, and the trapping efficiency is improved.
(4) The method fully utilizes the component characteristics of the lead glass and the waste automobile catalyst, realizes the synergistic treatment of two solid wastes through one-step high-temperature smelting, fully utilizes the sensible heat of the melt, prepares the non-metal component into a microcrystalline glass product with high added value, realizes the harmlessness and high-value recycling of the lead glass and the waste automobile catalyst, and has obvious environmental and economic benefits.
Drawings
FIG. 1 is a process flow diagram of the method for co-processing lead glass and waste catalyst provided by the present invention.
Detailed Description
The technical solution of the present invention will be described in detail by specific examples.
In the following examples, the agents used are all commercially available. The concentrations or contents in the respective examples are mass percentages.
The lead glass treated in each example and the analysis of the components of the spent catalyst are shown in tables 1 and 2, respectively.
TABLE 1 lead glass composition
Composition (I)
|
SiO2 |
PbO
|
CaO
|
Al2O3 |
K2O
|
Na2O
|
The mass percentage content
|
50.1%
|
22.4%
|
3.8%
|
3.9%
|
8.4%
|
4.1% |
TABLE 2 spent automotive catalyst composition
Composition (I)
|
SiO2 |
MgO
|
Al2O3 |
Pt
|
Pd
|
Rh
|
The mass percentage content
|
37.7%
|
10.6%
|
34.3%
|
348.6g/t
|
1056.1g/t
|
214.7g/t |
Example 1
The method for treating the waste catalyst and the lead glass by adopting the lead glass and the waste catalyst for cooperative treatment as shown in the figure 1 comprises the following steps:
crushing lead glass and waste catalyst to 0.074-0.178mm, taking 200g of waste catalyst, adding 200g of lead glass, 60g of calcium oxide and 4g of anthracite, adding 5g of cellulose as a binder, uniformly mixing in a mixing tank, pressing the mixture into powder by a powder tablet press
The sample was loaded into a graphite crucible.
Smelting the material in a medium frequency induction furnace, heating the sample to 1400 ℃, and blowing argon gas above the melt, wherein the flow of the argon gas is 0.5 L.min-1. After smelting for 2h, pouring the upper glass liquid into water, drying to obtain 335g of basic glass particles, placing the metal melt at the bottom of the crucible and the crucible in the air for cooling, and separating slag phase to obtain 35.4g of lead alloy.
And (3) finely grinding the base glass, putting the ground glass into a corundum crucible, putting the corundum crucible into a tubular resistance furnace, heating to 1100 ℃ at the heating rate of 5 ℃/min, preserving heat for 3h, and cooling along with the furnace to obtain the microcrystalline glass.
Through detection, the total content of platinum, palladium and rhodium in the lead alloy of the embodiment is 0.90%, the comprehensive recovery rate of platinum, palladium and rhodium is 98.1%, and the content of lead in the glass ceramics is 0.6%.
Example 2
The method for treating the waste catalyst and the lead glass by adopting the lead glass and the waste catalyst co-processing method shown in the figure 1 comprises the following steps:
crushing lead glass and waste catalyst to 0.074-0.178mm, and taking waste200g of catalyst, 300g of lead glass, 100g of calcium oxide, 7.5g of anthracite and 8g of cellulose are added and uniformly mixed in a mixing tank, and the mixture is pressed into granules by a powder tablet press
The sample was loaded into a graphite crucible.
Smelting the material in a medium frequency induction furnace, heating the sample to 1500 ℃, and blowing argon gas above the melt, wherein the flow of the argon gas is 0.4 L.min-1. After 4h of smelting, the upper glass liquid is poured into water, after drying, 432g of basic glass particles are obtained, the metal melt at the bottom of the crucible and the crucible are placed in the air for cooling, and 52.7g of lead alloy is obtained after slag phase separation.
And (3) finely grinding the base glass, putting the ground glass into a corundum crucible, putting the corundum crucible into a tubular resistance furnace, heating to 950 ℃ at the heating rate of 8 ℃/min, preserving heat for 1h, and then cooling along with the furnace to obtain the microcrystalline glass.
Through detection, the total content of platinum, palladium and rhodium in the lead alloy of the embodiment is 0.60%, the comprehensive recovery rate of platinum, palladium and rhodium is 98.3%, and the content of lead in the glass ceramics is 0.4%.
Example 3
The method for treating the waste catalyst and the lead glass by adopting the lead glass and the waste catalyst co-processing method shown in the figure 1 comprises the following steps:
crushing lead glass and waste catalyst to 0.074-0.178mm, taking 200g of waste catalyst, adding 250g of lead glass, 130g of calcium oxide, 5g of anthracite and 6g of cellulose, uniformly mixing in a mixing tank, and pressing the mixture into powder by a powder tablet press
The sample was loaded into a graphite crucible.
Smelting the material in a medium frequency induction furnace, heating the sample to 1300 ℃, and blowing argon gas above the melt, wherein the flow of the argon gas is 0.8 L.min-1. After 3h of smelting, the upper glass liquid is poured into water and dried to obtain 426g of basic glass particles, and the metal melt at the bottom of the crucible and the crucible are placed in the air togetherAfter cooling and separation of the slag phase, 44.7g of lead alloy was obtained.
And (3) finely grinding the base glass, putting the ground glass into a corundum crucible, putting the corundum crucible into a tubular resistance furnace, heating to 1000 ℃ at the heating rate of 10 ℃/min, preserving heat for 2h, and then cooling along with the furnace to obtain the microcrystalline glass.
Through detection, the total content of platinum, palladium and rhodium in the lead alloy of the embodiment is 0.71%, the comprehensive recovery rate of platinum, palladium and rhodium is 98.4%, and the content of lead in the glass ceramics is 0.7%.
Example 4
The method for treating the waste catalyst and the lead glass by adopting the lead glass and the waste catalyst co-processing method shown in the figure 1 comprises the following steps:
crushing lead glass and waste catalyst to 0.074-0.178mm, taking 200g of waste catalyst, adding 200g of lead glass, 80g of calcium oxide, 5g of anthracite and 8g of cellulose, uniformly mixing in a mixing tank, and pressing the mixture into powder by a powder tablet press
The sample was loaded into a graphite crucible.
Smelting the material in a medium frequency induction furnace, heating the sample to 1450 deg.C, and blowing argon gas with flow rate of 0.4 L.min above the melt-1. After smelting for 2h, pouring the upper glass liquid into water, drying to obtain 379.3g of basic glass particles, placing the metal melt at the bottom of the crucible and the crucible together in the air for cooling, and separating slag phase to obtain 37.5g of lead alloy.
And (3) finely grinding the base glass, putting the ground glass into a corundum crucible, putting the corundum crucible into a tubular resistance furnace, heating to 1150 ℃ at the heating rate of 7 ℃/min, preserving heat for 3h, and cooling along with the furnace to obtain the microcrystalline glass.
Through detection, the total content of platinum, palladium and rhodium in the lead alloy of the embodiment is 0.85%, the comprehensive recovery rate of platinum, palladium and rhodium is 98.0%, and the content of lead in the glass ceramics is 0.8%.