CN101519725A

CN101519725A - Method for extracting precious metal from auto-exhaust catalyst by hydrometallurgy and pyrometallurgy complex process

Info

Publication number: CN101519725A
Application number: CN200910094317A
Authority: CN
Inventors: 吴晓峰; 汪云华; 童伟锋; 赵家春; 范兴祥; 昝林寒; 李柏榆; 李楠
Original assignee: Kunming Institute of Precious Metals
Current assignee: Kunming Institute of Precious Metals
Priority date: 2009-04-09
Filing date: 2009-04-09
Publication date: 2009-09-02
Anticipated expiration: 2029-04-09
Also published as: CN101519725B

Abstract

The invention relates to a method for extracting precious metal from a disabled auto-exhaust catalyst, which comprises the following steps: 1. lixiviating precious metal from the disabled auto-exhaust catalyst by a hydrometallurgy process and obtaining precious metal concentrates after permuting lixivium; 2. lixiviating slag, collecting precious metal of the slag by a pyrometallurgy process to obtain a precious metal phase and selectively lixiviating base metal in the precious metal phase to obtain precious metal concentrates; and 3 combining the precious metal concentrates obtained in the first two steps and refining the precious metal concentrates to produce platinum, palladium and rhodium products. The invention compensates the deficiency that the percent recovery of the precious metal is low by simply treating the disabled auto-exhaust catalyst with the hydrometallurgy process and has the advantages that the contents of platinum, palladium and rhodium in the waste slag are smaller than 1g/t and the product purity reaches 99.95 percent.

Description

Wet-fiery integrated process is extracted the method for precious metal from automobile catalyst

Technical field

The present invention relates to from auto-exhaust catalyst to reclaim the method for platinum metals, be specifically related to the method for efficient recovery platinum metals from the auto-exhaust catalyst that comprises precious metal or various low-grade material.

Background technology

The precious metal tail-gas catalyst was brought into use in domestic automobile industry from 2000, the loading of freight waggon was about 200,000 in 2000, and China's light-duty vehicle output reached 5,200,000 in 2005, reached 7,000,000 in 2006, and tempo is doubled and redoubled.After 2006, domestic automobile all requires to install cleaning catalyst, and according to statistics, 2005～2006 years, China's automobile catalyst platinum metals consumption reached 20～30 tons.China's auto output surpassed 1,000 ten thousand in 2007, and following automobile volume of production and marketing will continue to increase, and the platinum metals consumption will constantly increase.Press the work-ing life of 80,000 kilometers of automobile catalysts and calculate, will welcome the peak period that automobile exhaust purifier is scrapped and changed the coming years.To this type of resource effective recycling, will have the potential economic worth.

The existing industrial process that reclaims the platinum metals from automobile catalyst mainly contains wet method, pressure cyanide method and plasma melting.

Plasma melting is in the presence of trapping agent, with the plasma melting automobile catalyst that lost efficacy, enriching and recovering platinum metals, is 20th century new and high technologies that just occur of the mid-80.Advantage: in the plasma melting process, because the heat flux height of plasma arc, fusion process efficient and speed obviously improve, and this method makes carrier melt slag making with high temperature, and temperature can reach more than 2000 ℃.Concentration ratio is big, flow process is brief, production efficiency is high, no waste water and exhaust emission.Shortcoming: when the plasma melting method is used to handle honeycomb-like cordierite carrier automobile catalyst, have the deficiency of two aspects: the one, the slag stickiness that trichroite generates is big, metal and slag separation difficulty; The 2nd, under smelting temperature, if there is carbon, silicon-dioxide in the trichroite (at least a portion) is reduced to elemental silicon, generate high silicon iron with the iron that adds as the platinum metals trapping agent, ferrosilicon forms new alloy mutually with the platinum metals, this alloy has extremely strong antiacid, alkali resistant character, makes subsequent technique very difficult.In addition because equipment is special, at present China still not have large-scale be the plasma melting device fabrication, plasma gun is short work-ing life, has limited its practical application, needs the material liner, to solve the refractory materials wear problem that Yin Gaowen causes.

It is the novel process that just proposes recent years that the pressure cyanide method is utilized the prussiate high-temperature pressurizing method that directly selectivity leach to reclaim the platinum metals from the inefficacy automobile catalyst, be to accelerate leaching velocity by improving temperature of reaction, make under the normal temperature and pressure can not cyaniding platinum palladium generation cyanogenation.Cyanide process platinum metals rate of recovery height, strong to material adaptability, there are not harmful waste residue and exhaust gas emission, waste liquid is easily handled.But prussiate belongs to violent in toxicity, and control is strict, difficult management, and facility investment is big.

Wet method is selected for use acid, alkali or the suitable Synergist S-421 95 of strong oxidizing property that waste material is all dissolved or is partly dissolved, and reclaims precious metal then from solution or insoluble slag.Processing cost is lower, technical feasibility.But the precious metal rate of recovery is low, and particularly the rate of recovery of rhodium is lower, and the intractable low-grade material.Though aforesaid method is simple and be widely used in the recovery of precious metal in the auto-exhaust catalyst, but it is all not thorough to reclaim precious metal, residue all contains a certain amount of precious metal, be low to moderate tens gram tons, high to a few hectogram tons, mainly adopt wet method from spent automotive exhaust catalysts, to extract precious metal in China at present.

Summary of the invention

The present invention be directed to deficiency and defective that existing Wet technique exists, proposed a kind of efficient method of from spent automotive exhaust catalysts, extracting platinum, palladium, rhodium.Adopt wet-fiery integrated process to remedy simple employing wet processing spent automotive exhaust catalysts and caused the low defective of the precious metal rate of recovery, make it have the precious metal rate of recovery more efficiently than existing processes, looser operational condition, and be easy to industrial realization.

Technical scheme of the present invention is:

1, with crusher spent automotive exhaust catalysts is carried out fragmentation, utilize pulverizing mill to pulverize then, and in broken and abrasive dust process, add water spray or water smoke;

2, render to the spent automotive exhaust catalysts powder in the hydrochloric acid soln and add oxygenant and leach wherein precious metal, filter, with precious metal solution with leach residue and separate;

3, iron powder and zinc powder are joined precious metal solution and replace, obtain the precious metal concentrate;

4, pack into after leaching residue and trapping agent, slag former mixing and place chamber type electric resistance furnace or the interior intensification melting of electric arc furnace in the clay plumbago crucible, after the fusion, constant temperature for some time, precious metal enters alloy phase to be separated with slag;

5, gained is contained the alloy phase selectivity leaching base metal wherein of precious metal, obtain the precious metal concentrate;

6, the precious metal concentrate of step 3 and 5 is merged carry out refining output platinum, palladium, rhodium product.

The present invention compared with prior art has the following advantages and beneficial effect:

1, owing to there is pyrogenic process that the precious metal that it leaches in the residue is further reclaimed, the processing condition of the precious metal among the present invention in the wet method leaching spent automotive exhaust catalysts are comparatively loose, for example, only adopt the precious metal in the hydrometallurgic recovery spent automotive exhaust catalysts, common before leaching to carrying out the roasting carbonization treatment to improve the leaching yield of precious metal to spent automotive exhaust catalysts, can save this processing step in the present invention, simplify flow process, reduce production cost.In Chinese patent CN1385545A, be to improve the leaching yield of precious metal, extraction temperature 〉=100 ℃, extraction temperature is about 80 ℃ in the present invention, and temperature is low can to reduce solution evaporation, cuts down the consumption of energy.

2, leach the residue melting technology and adopted new smelting formula, can capture precious metal efficiently from leach residue, bullion content makes it have the precious metal rate of recovery more efficiently than existing processes less than 1g/t in the metallurgical slag

3, adopting wet-fiery integrated process to remedy simple employing wet processing spent automotive exhaust catalysts and caused the low defective of the precious metal rate of recovery, is the country that a platinum metals lacks particularly in China, and precious metal reclaims the saving that the interests resource is arranged efficiently.

The present invention be directed to deficiency and defective that prior art exists, proposed a kind of efficient method of from spent automotive exhaust catalysts, extracting platinum, palladium, rhodium.Make it have better environment friendly than existing processes, the precious metal rate of recovery more efficiently, and be easy to realize.

Description of drawings

Fig. 1 is the process flow sheet of the invention process example.

Embodiment

1, leaches

The automobile spent catalyst at first carries out fragmentation, and powder process is got 200g at every turn it is added in the hydrochloric acid soln, heats up about 80 ℃, feeds chlorine, stirs and leaches, filter,

The leaching result is as follows:

2, displacement

Leach liquor is placed beaker, add iron powder earlier and replace, add zinc powder more earlier and replace, precipitation precious metal wherein obtains the precious metal concentrate, and the result is as follows in displacement:

3, melting

Get the automobile spent catalyst and leach residue, add trapping agent, slag former and reductive agent, behind the mixer mixing, in the clay-graphite crucible of packing into, place in the high temperature resistance furnace, in 1400 ℃ of constant temperature 0.5 hour, after finishing, melting takes out, be cooled to room temperature, melted material is poured out, at this moment melt is divided into precious metal alloys and smelting slag two-phase, and with slag sample preparation in sampling machine, sample send analyzing and testing platinum, palladium, rhodium content wherein.

Melting trapped experimental result is as follows:

4, selectivity leaches

Take by weighing precious metal alloys 100 grams, the sulphuric acid soln 1200ml of preparation 3.33N is added to precious metal alloys in the sulphuric acid soln solution that has prepared at every turn, stirring at room 5 hours, and vacuum filtration, residue washing 3 times is dried, is weighed.

High and low metal separation experimental result is as follows:

Take by weighing leached mud 10 grams at every turn one time, precious metal alloys are added in the sulphuric acid soln that has prepared, sulfuric acid concentration is 4N, places in the thermostat water bath, be warming up to 75 ℃, constant temperature stirred 7.5 hours, vacuum filtration, residue washing 4 times is dried, is weighed, and obtains the precious metal concentrate.

High and low metal separation secondary leaching experiment result is as follows:

Claims

1, a kind of method of extracting precious metal from spent automotive exhaust catalysts is characterized in that this technology carries out according to the following steps:

1), spent automotive exhaust catalysts is carried out fragmentation, utilizes pulverizing mill to pulverize then, and in broken and abrasive dust process, add and spray water or water smoke with crusher;

2), render to the spent automotive exhaust catalysts powder in the hydrochloric acid soln and add oxygenant and leach wherein precious metal, filter, with precious metal solution with leach residue and separate;

3), iron powder and zinc powder joined precious metal solution replace, obtain the precious metal concentrate;

4), place chamber type electric resistance furnace or the interior intensification melting of electric arc furnace in the clay plumbago crucible of packing into after leaching residue and trapping agent, slag former mixing, after the fusion, constant temperature, precious metal enter alloy phase to be separated with slag;

5), alloy phase selectivity that gained is contained precious metal leaches base metal wherein, obtains the precious metal concentrate;

6), with step 3) and 5) the precious metal concentrate merge and to carry out refining output platinum, palladium, rhodium product.

2, the method for from spent automotive exhaust catalysts, extracting precious metal according to claim 1, it is characterized in that step 2) described render in the hydrochloric acid soln and add oxygenant leach wherein precious metal, filter, be meant: add in the hydrochloric acid soln, heat up about 80 ℃, feed chlorine, stir and leach and filter.

3, the method for from spent automotive exhaust catalysts, extracting precious metal according to claim 1, it is characterized in that step 4) is described places intensification melting in chamber type electric resistance furnace or the electric arc furnace, after the fusion, constant temperature for some time is meant: place in the high temperature resistance furnace, in 1400 ℃ of constant temperature 0.5 hour.

4, the method for from spent automotive exhaust catalysts, extracting precious metal according to claim 1, it is characterized in that the described selectivity leaching of step 5) is meant: compound concentration is the sulphuric acid soln of 3.33～4N, precious metal alloys are added in the sulphuric acid soln that has prepared, place in the thermostat water bath, be warming up to 30～80 ℃, constant temperature stirred 5～7.5 hours, vacuum filtration, residue washing 2～4 times is dried, is weighed, and obtains the precious metal concentrate.