Method for recovery of platinum metal-containing sludge
FIELD: sludge recovery from surface depositions of chemical equipment.
SUBSTANCE: invention relates to method for recovery of sludge containing platinum-group metals from equipment using platinum metal-based catalysts. Method includes treatment with aqueous solution of active chemical agent (e.g. sodium-ammonium-substituted ethylenediaminetetraacetic salts) while controlling pH value and removing sludge retained on treated surface with diluted aqueous solution of mineral salts or mixture thereof. pH value is adjusted at 2-10, preferably at 3-9 by adding of organic acid selected from group containing citric, oxalic, maleic, phthalic, adipic, glutaric, succinic acids or basic agents selected from sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, and hydrochloric acid, sulfuric acid or phosphoric acid is used as mineral acid.
EFFECT: recovery platinum-group metal with improved yield.
4 cl, 1 tbl, 12 ex
The invention relates to the technology of extracting sludge containing platinum group metals (PGMs)from deposits on the surfaces of equipment of chemical plants using the catalysts containing these metals and losing them in the process of operation.
During long-term operation units, for example, in the production of non-concentrated nitric acid, heat exchange surfaces, the accumulation of IPY by the condensation of vapors of their oxides. At the same time there and on the inner walls of the apparatus are deposited fine particles of sludge containing PGM separated mechanically from the surface of the catalyst gauzes. As a result of significant quantities of PGMs are tubes in boilers, condensers-condensers, Cuba absorption column, the bottoms of storage of finished products.
The method for extracting sludge containing metals of the platinum group of deposits on surfaces of the apparatus installations using platinum catalysts, including the processing of these surfaces with an aqueous solution of the active chemical agent in the presence of circulation of the solution along the surface being cleaned and bubbling air into the treatment zone followed by filtration of the separated sludge from the solution. As the active agent is proposed to use three groups of chemicals, sharply distinguishing the I in its properties: mineral and organic acids, alkalis, amines [RF Patent №2083261, 1996, 22, 11/00].
The disadvantages of this method is the necessity of the use of forced circulation of the active chemical agent in conjunction with air sparging, which complicates the process and increases the corrosion of the base metal. The particle size of the formed sludge is very small, which makes use of to highlight filtering. Some of the used chemicals cause increased corrosion even in the absence of bubbling and circulating. Recommended concentrations of these reagents (3-6%) is too high, which leads to increased their expenditure on treatment.
Closest to the invention is a method for extracting slurry containing platinum group metals from deposits on the surfaces of the apparatus units, using catalysts based on platinum, including first processing deposits with an aqueous solution of the active chemical agent to adjust pH of the medium, and then removing remaining on the treated surfaces of the sludge. As an active chemical agent is used an aqueous solution of fluoride and/or hydrohloride ammonium, pH adjustment in the range of 3-9,5 lead ammonia. To remove the loosened sludge from the treated surface using a sparging or mechanical sobremisana [RF Patent №2188246, 2000, From 22 In 11/00].
N the drawbacks of this method consist in the use of sparging air or mechanical Sobrevivencia, what complicates the cleaning process. The concentration of the active chemical agent is too high 3-5%, which leads to increased consumption of reagents for treatment. Regulation of pH with ammonia is quite difficult, corrosion of the base metal equipment at low pH high, especially in the presence of air sparging. The particle size of the formed sludge is very small, which makes use of to highlight filtering. Processing time the reagent is large (~24 hours).
The present invention is directed to solving the following technical tasks: simplify the extraction process sludge, reduced consumption of reagents, reducing the corrosive effects on the treated surface, reducing processing time while maintaining a high degree of extraction of platinum group metals.
The technical result is achieved by a method of extraction of sludge containing metals of the platinum group of deposits on the surfaces of equipment and piping installations using catalysts based on platinum, including first processing deposits with an aqueous solution of the active chemical agent to adjust pH of the medium, and then removing remaining on the treated surface of the sludge. According to the invention as the active chemical agent use sodium ammonization salt atlantium tetraoxane acid, and removing remaining on the treated surface of the sludge is carried out by treatment with an aqueous solution of diluted mineral acids or mixtures thereof. The adjustment of pH in the region of 2-10, preferably 3-9, carry out the addition of organic acids from the group of citric, oxalic, maleic, phthalic, adipic, glutaric, succinic or alkaline reagents from the group of: caustic soda or caustic potash, carbonate of sodium or potassium, ammonium water. As a mineral acid using hydrochloric, sulfuric, phosphoric acid or mixtures thereof.
Distinctive features of the method according to the present invention lies in the fact that the treatment of the sediments as the active chemical agent use sodium ammonization salt ethylenediaminetetraacetic acid adjusted pH in the region of 2-10, and removing remaining on the treated surface of the sludge is carried out by treatment with an aqueous solution of diluted mineral acids or mixtures thereof.
Additional distinguishing features are that the adjustment of pH in the region of 2-10, preferably 3-9, carry out the addition of organic acids from the group of citric, oxalic, maleic, phthalic, adipic, glutaric, succinic or alkaline reagents from the group caustic soda, caustic potash, sodium carbonate, potassium carbonate. As diluted min the mineral acids used salt, phosphoric, sulfuric, or a mixture thereof.
The present invention meets the condition of patentability - novelty”, as in the prior art failed to find technical solutions, the essential features which would coincide with all the signs in the first independent clause. The present invention meets the condition of patentability - “inventive step”, since the prior art has failed to find technical solutions, the hallmarks of which are aimed at providing the same technical problems, the solution of which the invention is directed.
The essence of the proposed method lies in the fact that when exposed to the sodium and ammonium salts of ethylenediaminetetraacetic acid (EDTA) at pH 2.0 to 10 (preferably 3 to 9) of the dense sludge on the treated surface are removed, mainly ions of Fe3+, Fe2+at pH 2.0-7 and/or mainly ions of Al, Si, Mg, Ca at pH 7-10, thick residue on the cleaned surface acquires a special structure and subsequent short-term exposure to concentrated solution of mineral acid leads to swift detachment in the form of flakes. This flaking particles have a relatively large size, which makes use of filtering is not needed, because they almost immediately settle to the bottom of cleansing the constituent unit. The nature of the reagents, as well as lack of circulation and bubbling dramatically reduce corrosion. The processing time of the active reagent is reduced by 2-4 times (on average, three times).
The invention is illustrated by the following examples.
Example 1. The outer surface of the tube bundles economizer installation of diluted nitric acid production by the so-called combined scheme, which are thick black deposits of Fe2O3+Fe2About3·1,2 H2About 50 g/m2containing 9.5% of the PGM process 5 hours with an aqueous solution containing 0,55% 2N-substituted salts of EDTA and 0.35% maleic acid. the pH of the solution during the course of treatment varies from 3.0 to 6.0. After processing the pipe heater for 20 minutes immersed in 4%aqueous solution of hydrochloric acid, which is accompanied by the almost complete destruction of the remaining sludge from treated surfaces (almost 100%removal of sludge from smooth surfaces). Removing PGM - 98,1%. The PGM content in the spent solution is less than 1 mg/L. Traces of corrosion on the basic material and welds not found.
Example 2. The outer surface of the tube bundles of the economizer, which are deposits of oxides of divalent or trivalent iron, 9.5% of the IPY, and -10% of compounds of Si and Al (trapped in deposits of refractory lining), obrabecim the Ute 6 hours with an aqueous solution, containing 0.35% of 4N-substituted EDTA, prepared by dissolving EDTA in aqueous solution of sodium carbonate. The initial pH of the solution of 4-substituted EDTA at the beginning of treatment equal to 9.2 at the end of the processing pH 7.5. After processing the pipe heater for 20 minutes immersed in 4%aqueous solution of hydrochloric acid, which is accompanied by the almost complete destruction of the remaining sludge from treated surfaces. Removing PGM - 97,0%, the content of platinum group metals in the spent solution of 2 mg/L. No corrosion of the base metal and welded joints of pipes.
Examples 3-9 are summarized in table 1.
Example 10 (the prototype). The outer surface of the tube bundles of the economizer from example 1 is treated for 24 hours with an aqueous solution containing 4% of NH4F at pH 3.0, while air flow through the impeller is placed under the pipe heater. At the end of the process the solution is filtered, separating crumbled sludge. The degree of extraction of PGMs is 97%. Corrosion of welds lined x-ray analysis.
Example 11 are summarized in table 1.
Set in the present invention, the technical problems are solved only with the observance of the processing sequence including a first processing deposits in an aqueous solution of sodium ammonization salt of EDTA in the claimed period of pH, and then removing remaining on the treated surface by semirestored diluted mineral acids. When changing this sequence on the back of the main positive effect is a high degree of extraction of PGM - drops, which is evident from the following example.
Example 12. The pipe heater with sediments from example 1 is treated first with 4%Hcl solution for 20 minutes, and then for 6 hours with an aqueous solution containing 0,55% 2N-substituted EDTA. The degree of surface cleaning 40-50%, and the degree of extraction of PGM - 25%.
Considering the above examples are obvious advantages of the proposed method for extracting sludge containing PGM compared with the known, namely:
1. Practically no corrosion at high efficiency extraction of PGM, which makes possible the repeated execution of the following operations on the same hardware.
2. The simplification of the processing result from the elimination of the purification technology-intensive and not always available at the work site operations circulation sparging and filtration.
3. Low consumption of reagents: the concentration of the active agent and organic acids do not exceed 1%.
4. A significant reduction in processing time.
It should be noted that the recommended range of initial pH of the working solution due to the increase in corrosion testing of pipes at pH<3 and increased losses of PGM with worked solutions at pH outside the range 2-9.
The high efficiency of the process, is explained by the selective effect of the active chemical agent in the respective ranges of pH values on individual items included in a thick residue on the treated surface. The result of such exposure dense precipitate is riddled with numerous thin cross-cutting channels through which mineral acid reaches the surface of the base metal, resulting in rapid removal of this sediment in the form of relatively large scales.
|Results purification of samples stills economizer with compositions of sediments on the surface of the examples No. 1 (a) and 2 (b) - according to the text.|
|# example||Active reagent and his concia in R-re, g/l||Regulated than pH||Source. pH R-RA||The final pH R-RA||Processing time active reagent per hour||What removes the sludge from the treated surface||The efficiency of extraction of PGM,%||Notes|
|1(a)||2Na-EDTA 5,5||Maleic acid||3,0||6,0||5||20 min exposure to 4%Hcl||98,1||the absence of corrosion|
|2(6)||4Na, EDTA 3,5||PA2CO3||8,9||7.5||6,5||20 min exposure to 4%Hcl||97.0||the absence of corrosion|
|3(a)||2Na-EDTA 5,5||citric acid||3,2||5,9||5,5||25 min 5% NSR||98,0||the absence of corrosion|
|4 (a)||2Na-EDTA 5.5||a mixture of glutaric, adipic and succinic acids*||3,1||5,8||6,0||20 min exposure to 4%Hcl||98,5||the absence of corrosion|
|5 (a)||2Na-EDTA 4,0||citric acid||1,8||4,3||5,0||30 min 5% N3RHO4||99,0||corrosion of the pipe welds. Loss of PGM with OTP. R-rum >2 mg/l|
|6(6)||4Na, EDTA 5,5||NaOH||10,0||7,1||6,0||30 min 5% N3RHO4||97,5||the absence of corrosion. Loss of PGM with OTP. R-rum >2 mg/l|
|7(6)||4Na, EDTA 5,5||Na2CO3||11,0||7,5||6,0||30 min 5% N3RHO4||98,0||the absence of corrosion. Loss of PGM >2 mg/l|
|8(6)||4Na, EDTA 6,0||KON||11,0||7,6||6.0||25 min 5% N3RHO4||99,0||the absence of corrosion. Loss of PGM with OTP. R-rum >2 mg/l|
|9 (a)||2Na-EDTA 5,0||oxalic acid||2,2||5,5||6,0||25 min 5% H2SO4||98,5||the absence of corrosion. Loss of PGM >1.5-2 mg/l|
|10 (a) **||NH4F 40,0||ammonia (NH4OH)||3,0||3,1||24||sparging air||97,0||Corrosion of welds|
|11 (a) **||NH4F 40,0||ammonia (NH4OH)||9,0||8,8||24||sparging air||70,0||Corrosi is missing. Unsatisfactory removal of deposits from the surface.|
|* is the waste product of caprolactam|
** examples of the method prototype
1. The method for extracting slurry containing platinum group metals from deposits on the surfaces of the apparatus units, using catalysts based on platinum, including processing deposits with an aqueous solution of the active chemical agent to adjust the pH of the environment and the subsequent destruction of remaining on the treated surface of the slurry, characterized in that the treatment of the sediments as the active chemical agent use sodium-substituted ammonium salts of ethylenediaminetetraacetic acid adjusted pH in the region of 2-10, and removing remaining on the surfaces of the sludge is carried out by treatment with an aqueous solution of diluted mineral acids or mixtures thereof.
2. The method according to claim 1, characterized in that the adjustment of pH is carried out in the field 3-9.
3. The method according to claim 1 or 2, characterized in that the adjustment of the pH is performed by adding an organic acid from the group of citric, oxalic, maleic, phthalic, adipic, glutaric, succinic or alkaline reagents from the group of: caustic soda, caustic potash, sodium carbonate, potassium carbonate.
4. The method according to claim 1, characterized in that the mineral KIS is from the use of salt, phosphoric, sulfuric.
FIELD: noble metal hydrometallurgy.
SUBSTANCE: invention relates to method for acid leaching of platinum method from secondary raw materials, in particular from ceramic support coated with platinum metal film. Target metals are leached with mixture of hydrochloric acid and alkali hypochlorite at mass ratio of OCl-/HCL = 0.22-0.25 and redox potential of 1350-1420 mV.
EFFECT: decreased leaching temperature, reduced cost, improved platinum metal yield.
FIELD: non-iron metallurgy, in particular reprocessing of lead cakes from zinc manufacturing.
SUBSTANCE: claimed method includes heat treatment of lead cake with flux followed by smelting wherein before heat treatment mixture of lead cake, calcium hydroxide, and clinker from lead cake milling is balled to produce pellets. Pellets have fineness preferably of 30-100 mm. Method of present invention affords the ability to increase total coefficient of lead recovery by 3.1 %.
EFFECT: decreased energy consumption and reduced dust content in exhaust gas.
2 cl, 1 tbl
FIELD: nonferrous metallurgy.
SUBSTANCE: claimed method comprises combining slags using extraction principle with number of extractions n approaching infinity. Depleting agent efficient in presence of reducing agent is selected from materials enriched with pyrite, pyrrotine, calcium sulfide, and calcium sulfate; metal and alloys mainly containing Si, Al, Fe, C, etc. as well as reducing and sulfidizing complexes consisting of sulfides, oxides, and reducing substances (C, Me). Carbonaceous reducers, utilized individually or in mixture, are any known carbonaceous reducers. Degree of metal Me recovery is in accordance with conventional extraction equation.
EFFECT: increased degree of recovery of nickel from slags, reduced consumption of depleting agent, reduced power consumption and loss of sulfur into gas phase.
6 cl, 1 tbl
FIELD: non-iron metallurgy, in particular reprocessing of aluminum waste.
SUBSTANCE: claimed method includes junk charge into premelted flux at ratio of 1:(5-10); heating up to melt temperature; smelting under flux layer, and separation of metal from flux. Equimolar mixture of sodium chloride and potassium chloride with addition of 2.9-52.6 % (in respect to total flux weight) magnesium fluoride is used as flux, and in melting process flux layer with thickness of 4.5-20 cm is maintained. Method affords the ability to conserve original composition and eliminate additional burdening with magnesium.
EFFECT: decreased burn-off loss, especially for magnesium, metal of improved quality.
4 cl, 3 tbl, 5 ex
FIELD: mining art; hydro-metallurgical processing of ores and concentrates; extraction of beneficial components by underground leaching, heap leaching, vessel leaching and tank leaching.
SUBSTANCE: proposed method includes preparation of material for leaching-out process, delivery of leaching solution, discharge, collection and reworking of productive solution; intensification of leaching-out process is performed through ultrasonic treatment of material which is preliminarily saturated with solution of reagent (or water)inert to beneficial component and dissolving harmful admixtures. After discharge of leaching solution (or water), beneficial component is leached-out by leaching solution till reduction of its concentration in productive solution corresponding to maximum level obtained during standard leaching-out process. Then periodic ultrasonic treatment of material is performed again at contact with leaching solution till concentration of beneficial component in productive solution gets equal to permissible level for reworking of this solution in settling plant. Periodicity of ultrasonic treatment is determined by special relationship; radiators are mounted in cylindrical cavities (wells) or on surface of material.
EFFECT: enhanced intensification and efficiency due to increased rate of extraction of beneficial components; reduced consumption of reagents.
5 cl, 3 dwg,1 ex
FIELD: metal recovery, in particular noble metals from technologically proof raw materials.
SUBSTANCE: method includes raw grinding to 0.2 mm; blending with batch containing halogen salts and/or oxygen-containing salts, and mixture opening: cake cooling, leaching with simultaneous reaction pulp agitation with hot water, and metal recovery from solution and insoluble residue. Opening is carried out in electrical furnace at 100-120oC preferably at redox potential of 1.8-2.6 V, by elevating of temperature up to 450-560oC at rate of 8-10oC/min and holding for 1-7 h at highest mixture redox potential. Opened and cooled cake is grinded and leached in opened agitator.
EFFECT: environmentally friendly method with increased yield; utilization of unconventional noble and non-iron metal sources.
1 cl, 2 tbl
FIELD: metallurgy; production of platinum and palladium concentrates and silver from platinum-containing raw materials.
SUBSTANCE: proposed method includes sulphatizing roasting and/or sulphatizing of platinum-containing raw material at temperature of 200-600 C for 1-17 hours. Cinder is molten with sodium chloride at mass ratio of 1:(1-10) at temperature of 600-900 C; fusion cake is leached-out with water at mass ratio of fusion cake to water equal to 1: (1-10) at temperature of 80-90 C. After filtration of this pulp filtrate and residue are obtained; filtrate settles separating the silver concentrate in form of sediment of insoluble salt of silver chloride from liquid phase. Silver concentrate is washed with solution of concentrated hydrochloric acid and water at mass ratio of 1:10; leaching residue is washed with solution of concentrated hydrochloric acid and water at ratio 1:1, after which it is washed with water. Washing water is mixed with liquid phase obtained after separation of silver chloride from filtrate and sediment in form of platinum-palladium concentrate is let to settle; this sediment is separated by filtration and is washed with water.
EFFECT: complete primary extraction of platinum metals from platinum-containing raw material; reduced toxicity; reduced duration of process; reduced power requirements.
1 tbl, 1 ex