WO2018006433A1

WO2018006433A1 - Recovery of palladium from catalyst materials

Info

Publication number: WO2018006433A1
Application number: PCT/CN2016/089495
Authority: WO
Inventors: Biqin CHEN; Zhenqiang Yang; Yuxin Song; Jun JIA; Ping Jiang; Michael B. Korzenski
Original assignee: Entegris, Inc.
Priority date: 2016-07-08
Filing date: 2016-07-08
Publication date: 2018-01-11

Abstract

Disclosed is a process for recycling palladium-containing catalyst materials, wherein the process comprises: (a) grinding the palladium-containing catalyst in a milling module; (b) removing palladium from the palladium-containing catalyst using a removal composition; (c) optionally (i) separating the palladium-containing catalyst from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a solid and a liquid, and (ii) rinsing the solid with a first rinse subsequent to separation. The process can efficiently recover palladium from the catalyst materials while minimizing the amount of chemicals and other resources used.

Description

RECOVERY OF PALLADIUM FROM CATALYST MATERIALS

FIELD

The present invention relates generally to processes for recycling catalyst materials to recover palladium and other precious metals.

DESCRIPTION OF THE RELATED ART

Precious transition metal ions and their coordination complexes find industrial applications as supported catalysts and performance chemicals in fine chemicals industries. For example， metals like Ag， Au， Pd， Pt and Rh are used in a variety of industrial applications as catalysts for oxidation， hydrogenation and dehydrogenation reactions. Palladium salt catalysts are also widely used in catalyzing such reactions as oxidation， dehydrogenation， hydrogenation， isomerization and dimerization. Similarly， coordination metal complexes of Pd， Pt， Ru and Rh are used as commercial catalysts in homogeneous conditions for hydroformylation and hydrogenation reactions. The efficient recovery and purification of platinum group metals， such as palladium and platinum， from spent catalyst is economically desired. Consequently， research efforts have been directed to develop processes for the substantial recovery of such metals from spent catalysts. Various polymeric materials， modified silica， zeolite and/or clay materials are often used as support for these metals. However， owing to difficulties in separation of metal complexes from product mixtures， heterogenized catalysts have been developed where coordination metal complexes are supported on polymeric or inorganic solid support like silica， carbon， zeolite， and alumina. Commercially， it is important to recover the precious metals from the support to the maximum extent possible once the catalyst is deactivated.

In certain situations， the catalysts are deactivated during the reaction cycle or subsequent work-up and the reaction effluent may comprise various remnants， e.g.， complexes of various valence states for the metal ions. In many cases， the presence of excessive contaminants reduces the efficacy of recycling of the catalyst. In view of the environmentally stipulated restrictions on disposal of metal containing waste， effective recovery of the residual precious metals is of paramount importance for a process to be environmentally acceptable and economically viable.

Furthermore， during the recovery of precious metals from ore or scrap including spent catalysts， the use of solvent extraction to separate the precious metals from one another and from base metals that may also be present is becoming more widespread. The hydrometallurgical processes employed for the separation and recovery of the platinum group metals， (e.g.， platinum， palladium and rhodium) ， typically involve dissolving the metal ions by some type of oxidative acidic chloride leach， typically with aqua regia or hydrochloric acid/chlorine gas followed by solvent extraction.

An efficient and environmentally sustainable process for recovering palladium and other precious metals from palladium-containing catalysts has not been developed. The process should efficiently recover palladium from the catalyst materials while minimizing the amount of chemicals and other resources used.

SUMMARY

Embodiments of the invention relate generally to systems and processes for recycling palladium-containing catalysts to separate precious metals， e.g.， palladium， for reuse and/or recovery.

Embodiments of the invention relate to integrated， intelligent systems and processes for recycling palladium-containing catalysts.

In one embodiment， a process for recycling palladium-containing catalyst is described， wherein the process comprises：

(a) optionally one or more of (i) grinding the palladium-containing catalyst in a milling module， (ii) processing the palladium-containing catalyst to remove at least one other chemical species， and/or (iii) crushing the palladium-containing catalyst；

(b) removing palladium from the palladium-containing catalyst using a removal composition； and

(c) optionally (i) separating the palladium-containing catalyst from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a solid and a liquid， and (ii) rinsing the solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts. In another embodiment， a process for recycling palladium-containing catalyst is described， wherein the process comprises：

(a) ashing the palladium-containing catalyst in a furnace module to yield a first solid comprising ash；

(b) optionally grinding the first solid in a milling module；

(c) leaching palladium from the first solid using a first removal composition； and

(d) optionally (i) separating the first solid from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a second solid and a liquid， and (ii) rinsing the second solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts.

Other aspects， features and advantages will be more fully apparent from the ensuing disclosure and appended claims.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates generally to systems and processes for recycling palladium-containing catalyst materials to obtain precious metals for reuse and/or recovery. More particularly， the present invention relates generally to systems and processes for recycling palladium-containing catalyst materials to more efficiently separate and recover precious metals， e.g.， palladium， while simultaneously minimizing the use of chemicals and other resources. The system and process of using may be controlled by one or more programmable logic controllers (PLC) that coordinate and regulate automated process steps in the apparatus. The one or more PLCs allow multiple different processing modules to operate simultaneously through the apparatus， providing maximum throughput per square foot of factory space. Multi-tasking capability includes scheduling software that provides the system the intelligence necessary to be able to concurrently process multiple modules and multiple processes， when process times in each tank may not be balanced. Process recipes and procedures based on the type of palladium-containing catalyst， as well as batch size， can be stored in PLCs and automatically or manually initiated at the time batches of palladium-containing catalyst enter the process stream. In one embodiment， each module has at least one PLC. Further， when necessary， a supervisory control and data acquisition (SCADA) device or equivalent thereof and/or a communication network can be used to control the one or more PLCs. The systems and processes described herein enable high volume processing of catalyst material with precious metal recovery efficiencies of greater than 80％， preferably greater than 90％and more preferably greater than 95％.

As used herein， “precious metals” include the metals gold， silver， platinum， palladium， rhodium， iridium， osmium， rhenium， ruthenium and alloys comprising same.

As used herein， “base metals” corresponds to iron， nickel， zinc， copper， aluminum， tungsten， molybdenum， tantalum， magnesium， cobalt， bismuth， cadmium， titanium， zirconium， antimony， manganese， beryllium， chromium， germanium， vanadium， gallium， hafnium， indium， niobium， rhenium， thallium， alloys comprising same， and combinations thereof.

As used herein， “about” is intended to correspond to greater than or less than no more than 5 ％of the stated value.

As used herein， “substantially removed” is defined herein to be that more than 95 wt. ％of the material originally present is removed， dissolved or otherwise solubilized， preferably more than 98 wt. ％， more preferably more than 99 wt. ％， and most preferably more than 99.9 wt. ％. “Not substantially removed” is defined herein to be that less than 5 wt. ％of the material originally present is removed， dissolved or otherwise solubilized， preferably less than 2 wt. ％， more preferably less than 1 wt. ％， even more preferably less than 0.1 wt. ％， and most preferably less than 0.001 wt％.

As used herein， the term “leaches” or “removes” corresponds to the complete or partial removal or extraction of the particular metal or other desired material into the particular removal composition. The particular metal or other desired material is dissolved or otherwise solubilized in the particular removal composition， preferably dissolved.

As defined herein， “crushing” corresponds to any method that substantially exposes the palladium-containing catalyst material to a removal composition， e.g.， cracking， pulverizing or shredding the palladium-containing catalyst material.

As defined herein， “milling” corresponds to any method that reduces a larger material into a smaller material using a compressive force， thereby increasing the surface area of the material that can be exposed to a removal composition for removal of metals and other desired materials therefrom. Milling can be accomplished with a negligible rise in temperature of the materials being milled.

As defined herein， “grinding” corresponds to any method that reduces a larger material into a smaller material using a shearing force or a cutting action， thereby increasing the surface area of the material that can be exposed to a removal composition for removal of metals and other desired materials therefrom.

It should be appreciated that the “removal compositions” described herein are specifically and/or selectively formulated to remove one or more metals or other desired materials. Further， the removal compositions can be proprietary， commercially available， or both.

As defined herein， a “module” corresponds to a distinct system and corresponding process that is capable of facilitating the chemical， mechanical， thermal (i.e.， heat) ， and physical processes needed to accomplish a desired end goal， for example， the leaching of palladium from the palladium-containing catalyst material. The modules may be connected and/or operate serially or in parallel， with or without intervening steps therebetween， or not connected at all， e.g.， a module could be off-site relative to other modules or a module may be within another module.

As used herein， “ashing” or “to ash” corresponds to a process wherein an organic material， also known as “ashable content， ” is reacted with air or other oxygen source at a high temperature， e.g.， burned， to leave only noncombustible material.

As used herein， “slurry” corresponds to a mixture of solids in a liquid， for example， particle-containing solids in a liquid. Slurries tend to be a thick fluid and can be pumped and the solid will settle as a result of gravity if left in an unagitated state.

As defined herein， a “loaded” removal composition corresponds to a removal composition that is substantially saturated with the metal ions or has otherwise reached a predetermined concentration or threshold of a constituent of a removal composition (e.g.， a certain metal ion) or pH. Considered another way， the loaded removal composition can no longer substantially dissolve or solubilize the metal (s) it was intended to remove.

As defined herein， a “loaded” rinse liquid corresponds to a rinse liquid that no longer effectively rinses the solid or has otherwise reached a predetermined concentration or threshold of a chemical constituent (e.g.， a certain metal ion) or pH.

As defined herein， “moving means” correspond to manual or mechanical systems for moving objects from one location to another location including one or more of a conveyor belt， a conveyor track， a conveying wheel， a conveying roller， gravity conveyor， robots， a robotic loading arm with a moving mechanism， Schmidt conveyors， overhead conveyors with powered channels/tracks， tracks， elevators， collection conveyors， monorails， belts， link chains， transporter with wheels， trucks， hand trucks， trays， fork lifts， boom lifts， scissor lifts， straddle lifts， cantilever lifts， post lifts， vertical lifts， horizontal lifts， trolleys， pallets， dollies， caddies， pulleys， clamps， hoists， hooks， forks， stackers， bucket elevators， carousels， cranes， guided vehicles， carts， pumps， slurry pumps， or combinations of the foregoing. For the purposes of this application， any conveying systems can include speed control and/or variable speed.

As defined herein， “agitation means” or ″agitation″ includes， but is not limited to， top stirrers/mixers， bottom stirrers/mixers， side stirrers/mixers， screw agitators， rocking or rotating means， rotary mixers， sonication， ultrasonic energy， blenders， blades， dispersers， rotors， propellers， recirculators， baffles， impellers， internal fins or augers within containing means that result in agitation when rotated， and any combination thereof.

As defined herein， “liquid-solid separation means” include， but are not limited to， centrifugation (e.g.， decanter， cone-shaped) ， decanting， filtering， drying， evaporation， osmosis， sedimentation， precipitation， filter presses， and combinations thereof.

As defined herein， “ventilation means” corresponds to forced air (mechanical) ventilation such as local exhaust ventilation (hoods， ductwork， air cleaning device， fans， exhaust stacks， scrubbers， and combinations thereof) .

As defined herein， a “container” or a “containing means” can include， but is not limited to， gaylords， drums， baskets， tanks， bags， barrels， boxes， hoppers， supersacks， bins， bottles， and cylinders.

For the purposes of the present disclosure， a “monorail” preferably includes at least one of layout flexibility， tracks， rails， slopes， switches turntables， interlocks， entry/exit sections， as well as curves. The monorail may be elevated and/or run at grade and can connect to other systems， such as conveyors， elevators， or cranes. The monorails can be arranged to move a “container” or a “containing means. ” The monorail can also be arranged to move boards and/or components from one module to another.

As defined herein， “intelligent” refers to the control of one or more systems and/or processes of using said systems using one or more programmable logic controllers (PLC) that coordinate and regulate automated process steps in the systems. PLCs allow multiple different processing modules， and multiple different containing means within each module， to operate simultaneously through the apparatus， providing maximum throughput per square foot of factory space. Multi-tasking capability includes， but is not limited to， scheduling software developed that provides the system the intelligence necessary to be able to concurrently process and sample multiple modules and multiple containing means within each module， recipe input and adaptation， materials handling， real-time monitoring， sensing， data acquisition and analysis， remote and/or wireless use and communication， and any combination thereof. The intelligent system (s) and/or process (es) can communicate with other system (s) and/or process (es) securely， using a network.

As defined herein， an “intelligent system” corresponds to a computer-based system that has the capacity to gather and analyze data and communicate with itself and/or other systems within the apparatus. For example， a module as described herein， can analyze data and communicate with itself and/or another module within the apparatus， thereby making adjustments to the process and/or recipe. In addition， an intelligent system is capable of shutting down a portion of， or the entire， system to ensure worker safety. Moreover， an intelligent system is capable of determining when maintenance to the hardware and/or software must occur.

As defined herein， a “recipe” corresponds to the parameters used and/or programmable and/or input and/or chosen and/or adjusted to ensure maximum process efficiency， maximum metal removal， and minimum waste production using the system and process described herein. Parameters considered include， but are not limited to， ratio of solid to liquid during removal process， processing time， processing temperature， processing sequence， addition rates， the palladium-containing catalyst being processed， the amount of palladium-containing catalyst being processed， concentration of chemicals in the removal compositions， order of addition， the amount of effluent that must be disposed of properly， type of agitation means， speed of agitation， how many times the removal or rinse composition has been reused/recirculated， type of material being processed， concentration of metal ion constituents， current and voltage changes， and other pre-specified thresholds.

Many different types of palladium-containing catalysts are known in the art. For example， catalytic converters operate by converting the polluting exhaust gases (carbon monoxide， nitrogen oxides and unburnt petrol) into non-toxic emissions such as water， nitrogen and carbon dioxide via a ceramic monolith containing noble metals in a wash-coat， nowadays mainly palladium and to a lesser extent platinum and rhodium. In fact， the palladium， platinum and rhodium noble metal content has changed in the course of time with a substantial increase in the palladium content with respect to platinum and rhodium. Dissolution of the palladium contained in these ceramic monoliths consisting for the most part of complex systems/composite materials， for example Pd _(0.7％w/w) /Al₂O₃ or Pd _(0.7％w/w) /Ce_0.6Zr_0.4O₂ _(10％w/w) /Al₂O₃ or Pd _(2.8％w/w) /Ce_0.6Zr_0.4O₂ _(10％w/w) /Al₂O₃， is not an easily solvable technical problem. In catalytic converters the palladium is present in a very small quantity with respect to the weight of the wash-coat and ceramic monolith and is highly dispersed on the surface of the support. The strong interaction of the palladium with the ceria/zirconia solid solution， designed to prevent sintering of the catalytic converter and therefore prolong its life， makes extraction of the palladium difficult. Furthermore， the capacity of ceria oxide based systems to easily release reticular oxygen reduces the metallic character of the palladium particles. For the purposes of the present invention， catalytic converter material comprising palladium are hereinafter referred to as ″catalystl″ or ″C1. ″

Another kind of palladium-containing catalyst material is often referred to as ″palladium on alumina″ balls， which generally comprise an alumina core with a relatively thin crust comprising palladium and range in diameter from 3-10 mm. The palladium on alumina balls typically comprise about 0.1 to about 1 wt％palladium. The palladium on alumina balls are generally used for deoxidation or dehydrogenation processes in the petrochemical， polymer， chemical， and pharmaceutical industries. For the purposes of the present invention， palladium on alumina balls are hereinafter referred to as ″catalyst3″ or ″C3. ″

Still another kind of palladium-containing catalyst material is a carbon-based catalyst typically used for catalytic hydrogenations. The carbon-based palladium-containing catalyst is black in appearance and is also referred to as ″palladium on carbon， ″ and ″Pd/C. ″ The amount of palladium present is typically about 5 to about 10 wt％. For the purposes of the present invention， palladium on carbon is hereinafter referred to as ″catalyst4″ or ″C4. ″

It was surprisingly discovered that the efficiency of the process of removing palladium from the catalyst was dependent on the source of the catalyst. Each favored process will be described hereinbelow.

Processes to Reclaim Palladium from Catalyst1

Five different samples of C1 were obtained and analyzed for chemical content， as provided hereinbelow in Table 1. In general， the palladium-containing catalyst1 can comprise palladium， manganese， cerium， calcium， aluminum， and magnesium and either platinum or rhodium or both platinum and rhodium. The palladium concentration in the catalyst1 was experimentally determined to be in a range from about 500 to 2500 ppm.

Table 1： Chemical content of samples of Catalyst1

	C1-A/ppm	C1-B/ppm	C1-C/ppm	C1-D/ppm	C1-E/ppm
obtained shape	honeycomb	honeycomb	shredded	shredded	shredded
Sr	330.09
Mn	8020.13	6953.38	13608.43	1756.68	9514.96
Pd	2551.80	779.91	2497.86	425.69	779.24
Pt	177.78	78.87	0.00	0.00	0.00
Rh	0.00	34.43	100.40	34.46	14.42
Ce	2038.56	6523.63	2952.27	4760.27	3147.85
Zn	3995.89
Cr	227.27
Ca	＞9510	＞113 16.17	＞6029.49	＞2873.52	＞7707.71
Al	＞42330	＞55967.16	＞83952.02	＞45246.33	＞58611.92
Mg	＞24120	＞23753.82	＞11424.50	＞13382.05	＞6964.91

In a first aspect， a process for recovering palladium from palladium-containing catalyst C1 is described， said process comprising contacting the palladium-containing catalyst C1 with a first removal composition at process conditions necessary to substantially remove more than about 90％， preferably more than about 92.5％， and most preferably more than about 95％of the palladium contained in the palladium-containing catalyst C1. The process conditions comprise temperature in a range from about 20℃ to about 100℃， preferably about 40℃ to about 80℃， at time in a range from about 1 min to about 200 min， preferably about 30 min to about 90 min. Preferably， the process includes moving the palladium-containing catalyst material within a module automatically or manually， and/or moving the palladium-containing catalyst material from module to module， automatically or manually， using a moving means. The process may be controlled by one or more controlling device including， but not limited to， PLCs that coordinate and regulate one or more automated process steps.

With regards to the process of the first aspect， the contacting comprises immersing the palladium-containing catalyst C1 in the first removal composition within a containing means， optionally with agitation. The ratio of solid catalyst C1 to first removal composition can be in a range from about 1∶1 to about 1∶100 (solid to liquid) ， preferably about 1∶10 to about 1∶25 (solid to liquid) .

In a further embodiment， at the end of the prescribed contact， the palladium-containing catalyst C1 can undergo a separation S1 from the first removal composition using liquid-solid separation means and the separated solid catalyst C1 can be rinsed with a first rinse， wherein the first rinse preferably comprises water. The ratio of solid catalyst C1 to first rinse liquid can be in a range from about 1∶1 to about 1∶10 (solid to liquid) ， preferably about 1∶1 to about 1∶5 (solid to liquid) . Subsequent to separation S1， the first removal composition can be sent for further processing， either (i) the introduction of palladium-containing catalyst C1 that has not been processed for the chemical removal of palladium therefrom as described above or (ii) to post-contact processing to extract the palladium metal from the first removal composition comprising palladium ions， as described hereinbelow. In other words， the first removal composition can be reused in the contacting step until the first removal composition is loaded with palladium ions such that the dissolution or solubilization of palladium therein slows and is no longer efficient， as readily determined by the person skilled in the art. Once the first removal composition is loaded with palladium ions， it is sent for further processing to extract the palladium metal from the first removal composition comprising palladium ions， as described hereinbelow. At the completion of the rinse， the rinsed catalyst C1 can undergo a separation S2 from the first rinse using liquid-solid separation means and the first rinse liquid can be sent for further processing， either (a) to be used for further rinsing， (b) to post-rinsing processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or (c) to produce new first removal composition. In other words， the first rinse liquid can be reused until the first rinse liquid is no longer effective as a rinse， as readily determined by the person skilled in the art. Once the first rinse liquid is no longer effective as a rinse liquid， it can be sent for further processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or can be used to product new first removal composition. The solid catalyst C1 subsequent to separation from the first removal composition can be rinsed one time as described， or multiple times， for example， two times， three times， four times， or more， as needed to ensure that the palladium ions are removed from the solid catalyst C1.

In another embodiment of the process of the first aspect， the process further comprises (i) grinding the palladium-containing catalyst C1 in a milling module to yield a solid comprising ground materials， (ii) processing to remove other species， and/or (iii) crushing to yield a solid comprising crushed materials， said solid being subsequently contacted with the first removal composition at process conditions necessary to substantially remove more than about 90％， preferably more than about 92.5％， and most preferably more than about 95％of the palladium contained in the palladium-containing solid. In other words， the palladium-containing catalyst C1 may be ground， previously processed to remove other species， crushed， and/or in the shape of the original catalyst material when it is contacted with the first removal composition.

The apparatus for the process of the first aspect can comprise， consist of， or consist essentially of a containing means for the dissolution/solubilization of palladium， liquid-solid separation means， and optionally at least one rinse container， wherein the removal apparatus is capable of removing palladium from palladium-containing catalyst C1. The palladium-containing catalyst C1 may have been ground， previously processed to remove other species， crushed， and/or in the shape of the original catalyst material prior to contacting with the first removal composition. The apparatus can further comprise at least one of： a first removal composition container in liquid communication with the containing means for the dissolution/solubilization of palladium； at least one rinse liquid container in liquid communication with the at least one rinse container； at least one centrifuge； agitation means in at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one pump； heating/cooling means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one air input for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； real-time sampling and adjustment； programmable logic controllers or equivalent thereof； sensing means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； and ventilation means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container. Preferably， the apparatus is designed such that the palladium-containing catalyst C1， whether batch or otherwise， can move from container to container， automatically or manually， using a moving means. The containers of the apparatus can be operated in series with one another， with or without intervening parts. The apparatus may be controlled by one or more controlling devices including， but not limited to， PLCs that coordinate and regulate one or more automated process steps in the apparatus.

The processes of the first aspect are capable of maximizing the efficiency of precious metal， e.g.， palladium， removal. The processes ensure that the palladium-containing catalyst C1 is processed to ensure a minimization of resources (e.g.， chemicals， energy， hardware， software， footprint of the facility， water) ， a minimization of waste， and a maximization of metal reclaimed. This is accomplished， in part， using at least one programmable logic controller， which can be controlled by a SCADA device. It should be appreciated that depending on the module， the process can be either a wet process， a dry process， a chemical process， a physical process， an electrical process， a mechanical process， or some combination of more than one of the foregoing processes. For example， wet processing includes， but is not limited to， metal removal using chemicals and rinsing， while dry processing includes， but is not limited to， thermal processing (i.e.， heating) ， grinding， and burning. In one embodiment， each module has at least one PLC controlling it. In another embodiment， multiple modules have at least one PLC controlling them. When more than one PLC is present， a SCADA device can be used to control the one or more PLCs. A SCADA device is a computer-based system that monitors and controls industrial， infrastructure and facility-based processes. Although not discussed at length， the process of the first aspect also removes platinum and/or rhodium， when present.

Notably， the process of the first aspect does not involve pyrometallurgical chlorination.

In summary， the embodiments of the first aspect include a process for recycling palladium-containing catalyst material C1， wherein the process comprises， consists of， or consists essentially of：

(a) optionally one or more of (i) grinding the palladium-containing catalyst C1 in a milling module， (ii) processing the palladium-containing catalyst C1 to remove at least one other chemical species， and/or (iii) crushing the palladium-containing catalyst C1；

(b) removing palladium from the palladium-containing catalyst C1 using a first removal composition； and

(c) optionally (i) separating the palladium-containing catalyst C1 from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a solid and a liquid， and (ii) rinsing the solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts， and wherein the process efficiently recovers more than about 90％， preferably more than about 92.5％， and most preferably more than about 95％of the palladium contained in the palladium-containing catalyst C1. Preferably， the process includes moving the palladium-containing catalyst material within a module automatically or manually， and/or moving the palladium-containing catalyst material from module to module， automatically or manually， using a moving means. The process may be controlled by one or more controlling device including， but not limited to， PLCs that coordinate and regulate one or more automated process steps.

Processes to Reclaim Palladium from Catalyst3

Two different samples of C3 were obtained and analyzed for chemical content， as provided hereinbelow in Table 2. In general， the palladium-containing catalyst3， which is palladium on alumina balls， can comprise a substantial amount of aluminum as well as palladium， iron， zinc， and some nickel. The palladium concentration in the catalyst3 was experimentally determined to be in a range from about 600 to 800 ppm.

Table 2： Chemical content of samples of Catalyst3

	C3-A/ppm	C3-B/ppm
Al	＞37144.4	＞321082.0
Fe	＞5999.4	124.3
Pb	1139.0
Pd	813.4	634.0
Zn	708.7	539.8
Ni	253.0	5.1
Cu	65.8
Ag	31.1
Ca		3193.1
Pt		ND
Rh		ND

In a second aspect， a process for recovering palladium from palladium-containing catalyst C3 is described， said process comprising contacting the palladium-containing catalyst C3 with a second removal composition at process conditions necessary to substantially remove more than about 80％， preferably more than about 85％， and most preferably more than about 90％of the palladium contained in the palladium-containing catalyst C3. The process conditions comprise temperature in a range from about 20℃ to about 100℃， preferably about 40℃ to about 80℃， at time in a range from about 1 min to about 100 min， preferably about 1 min to about 30 min.

With regards to the process of the second aspect， the contacting comprises immersing the palladium-containing catalyst C3 in the second removal composition within a containing means， optionally with agitation. The ratio of solid catalyst C3 to second removal composition can be in a range from about 1∶1 to about 1∶100 (solid to liquid) ， preferably about 1∶10 to about 1∶25 (solid to liquid) .

In a further embodiment， at the end of the prescribed contact， the palladium-containing catalyst C3 can undergo a separation S1 from the second removal composition using liquid-solid separation means and the separated solid catalyst C3 can be rinsed with a first rinse， wherein the first rinse preferably comprises water. The ratio of solid catalyst C3 to first rinse liquid can be in a range from about 1∶1 to about 1∶10 (solid to liquid) ， preferably about 1∶3 to about 1∶5 (solid to liquid) . Subsequent to separation S1， the second removal composition can be sent for further processing， either (i) the introduction of palladium-containing catalyst C3 that has not been processed for the chemical removal of palladium therefrom as described above or (ii) to post-contact processing to extract the palladium metal from the second removal composition comprising palladium ions， as described hereinbelow. In other words， the second removal composition can be reused in the contacting step until the second removal composition is loaded with palladium ions such that the dissolution or solubilization of palladium therein slows and is no longer efficient， as readily determined by the person skilled in the art. Once the second removal composition is loaded with palladium ions， it is sent for further processing to extract the palladium metal from the second removal composition comprising palladium ions， as described hereinbelow. At the completion of the rinse， the rinsed catalyst C3 can undergo a separation S2 from the first rinse using liquid-solid separation means and the first rinse liquid can be sent for further processing， either (a) to be used for further rinsing， (b) to post-rinsing processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or (c) to produce new second removal composition. In other words， the first rinse liquid can be reused until the first rinse liquid is no longer effective as a rinse， as readily determined by the person skilled in the art. Once the first rinse liquid is no longer effective as a rinse liquid， it can be sent for further processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or can be used to product new second removal composition. The solid catalyst C3 subsequent to separation from the second removal composition can be rinsed one time as described， or multiple times， for example， two times， three times， or more， as needed to ensure that the palladium ions are removed from the solid catalyst C3.

In another embodiment of the process of the second aspect， the process further comprises (i) grinding the palladium-containing catalyst C3 in a milling module to yield a solid comprising ground materials， (ii) processing to remove other species， and/or (iii) crushing to yield a solid comprising crushed materials， said solid being subsequently contacted with the second removal composition at process conditions necessary to substantially remove more than about 80％， preferably more than about 85％， and most preferably more than about 90％of the palladium contained in the palladium-containing solid. In other words， the palladium-containing catalyst C3 may be ground， previously processed to remove other species， crushed， and/or in the shape of the original catalyst material when it is contacted with the second removal composition.

The apparatus for the process of the second aspect comprises， consists of， or consists essentially of a containing means for the dissolution/solubilization of palladium， liquid-solid separation means， and optionally at least one rinse container， wherein the removal apparatus is capable of removing palladium from palladium-containing catalyst C3. The palladium-containing catalyst C3 may have been ground， previously processed to remove other species， crushed， and/or in the shape of the original catalyst material prior to contacting with the second removal composition. The apparatus can further comprise at least one of： a second removal composition container in liquid communication with the containing means for the dissolution/solubilization of palladium； at least one rinse liquid container in liquid communication with the at least one rinse container； at least one centrifuge； agitation means in at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one pump； heating/cooling means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one air input for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； real-time sampling and adjustment； programmable logic controllers or equivalent thereof； sensing means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； and ventilation means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container. Preferably， the apparatus is designed such that the palladium-containing catalyst C3， whether batch or otherwise， can move from container to container， automatically or manually， using a moving means. The containers of the apparatus can be operated in series with one another， with or without intervening parts.

The processes are capable of maximizing the efficiency of precious metal， e.g.， palladium， removal. The processes ensure that the palladium-containing catalyst C3 is processed to ensure a minimization of resources (e.g.， chemicals， energy， hardware， software， footprint of the facility， water) ， a minimization of waste， and a maximization of metal reclaimed. This is accomplished， in part， using at least one programmable logic controller， which can be controlled by a SCADA device. It should be appreciated that depending on the module， the process can be either a wet process， a dry process， a chemical process， a physical process， an electrical process， a mechanical process， or some combination of more than one of the foregoing processes. For example， wet processing includes， but is not limited to， metal removal using chemicals and rinsing， while dry processing includes， but is not limited to， thermal processing (i.e.， heating) ， grinding， and burning. In one embodiment， each module has at least one PLC controlling it. In another embodiment， multiple modules have at least one PLC controlling them. When more than one PLC is present， a SCADA device can be used to control the one or more PLCs. A SCADA device is a computer-based system that monitors and controls industrial， infrastructure and facility-based processes. Although not discussed at length， the process of the second aspect also removes platinum and/or rhodium， when present.

In summary， the embodiments of the second aspect include a process for recycling palladium-containing catalyst material C3， wherein the process comprises， consists of， or consists essentially of：

(a) optionally one or more of (i) grinding the palladium-containing catalyst C3 in a milling module， (ii) processing the palladium-containing catalyst C3 to remove at least one other chemical species， and/or (iii) crushing the palladium-containing catalyst C3；

(b) removing palladium from the palladium-containing catalyst C3 using a second removal composition； and

(c) optionally (i) separating the palladium-containing catalyst C3 from the second removal composition using liquid-solid separation means subsequent to palladium removal to yield a

solid and a liquid， and (ii) rinsing the solid with a first rinse subsequent to separation， wherein the processes are positioned and/or operated in series with one another， with or without intervening parts， and wherein the process efficiently recovers more than about 80％， preferably more than about 85％， and most preferably more than about 90％of the palladium contained in the palladium-containing catalyst C3. Preferably， the process includes moving the palladium-containing catalyst material within a module automatically or manually， and/or moving the palladium-containing catalyst material from module to module， automatically or manually， using a moving means. The process may be controlled by one or more controlling device including， but not limited to， PLCs that coordinate and regulate one or more automated process steps.

Processes to Reclaim Palladium from Catalyst4

One of C4 was obtained and analyzed for chemical content， before and after ashing， as provided hereinbelow in Table 3. Prior to ashing， the carbon content in C4 was greater than 99 wt％. In general， the palladium-containing catalyst4 can comprise palladium， barium， chromium， and manganese.

Table 3： Chemical content of samples of Catalyst4

In a third aspect， a process for recovering palladium from palladium-containing catalyst C4 is described， said process comprising：

ashing the palladium-containing catalyst C4 in a furnace module to yield a solid comprising ash； and

leaching the palladium-containing catalyst C4 using a first removal composition at process conditions necessary to substantially remove more than about 90％， preferably more than about 95％， and most preferably more than about 98％of the palladium contained in the palladium-containing catalyst C4.

The ashing step improves the efficiency of the process because the carbon in the catalyst C4 interferes with the dissolution process of the palladium in the presence of the first removal composition. In one embodiment， the palladium-containing catalyst4 can be introduced to a furnace in the presence of air at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours， optionally but preferably followed by the introduction of hydrogen gas to the furnace at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours. The leaching process conditions comprise temperature in a range from about 20℃ to about 100℃， preferably about 40℃ to about 80℃， at time in a range from about 1 min to about 200 min， preferably about 30 min to about 120 min.

With regards to the process of the third aspect， the contacting comprises immersing the palladium-containing catalyst C4 in the first removal composition within a containing means， optionally with agitation. The ratio of solid catalyst C4 to first removal composition can be in a range from about 1∶10 to about 1∶200 (solid to liquid) ， preferably about 1∶70 to about 1∶120 (solid to liquid) .

In a further embodiment， at the end of the prescribed contact， the palladium-containing catalyst C4 can undergo a separation S1 from the first removal composition using liquid-solid separation means and the separated solid catalyst C4 can be rinsed with a first rinse， wherein the first rinse preferably comprises water. The ratio of solid catalyst C4 to first rinse liquid can be in a range from about 1∶1 to about 1∶10 (solid to liquid) ， preferably about 1∶3 to about 1∶5 (solid to liquid) . Subsequent to separation S 1， the first removal composition can be sent for further processing， either (i) the introduction of palladium-containing catalyst C4 that has not been processed for the chemical removal of palladium therefrom as described above or (ii) to post-contact processing to extract the palladium metal from the first removal composition comprising palladium ions， as described hereinbelow. In other words， the first removal composition can be reused in the contacting step until the first removal composition is loaded with palladium ions such that the dissolution or solubilization of palladium therein slows and is no longer efficient， as readily determined by the person skilled in the art. Once the first removal composition is loaded with palladium ions， it is sent for further processing to extract the palladium metal from the first removal composition comprising palladium ions， as described hereinbelow. At the completion of the rinse， the rinsed catalyst C4 can undergo a separation S2 from the first rinse using liquid-solid separation means and the first rinse liquid can be sent for further processing， either (a) to be used for further rinsing， (b) to post-rinsing processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or (c) to produce new first removal composition. In other words， the first rinse liquid can be reused until the first rinse liquid is no longer effective as a rinse， as readily determined by the person skilled in the art. Once the first rinse liquid is no longer effective as a rinse liquid， it can be sent for further processing to extract the palladium metal from the first rinse liquid comprising palladium ions， as described hereinbelow， or can be used to product new first removal composition. The solid catalyst C4 subsequent to separation from the first removal composition can be rinsed one time as described， or multiple times， for example， two times， three times， or more， as needed to ensure that the palladium ions are removed from the solid catalyst C4.

In another embodiment of the process of the third aspect， the process further comprises grinding the palladium-containing catalyst C4 in a milling module subsequent to ashing to yield a solid comprising ground materials， said solid being subsequently contacted with the first removal composition at process conditions necessary to substantially remove more than about 90％， preferably more than about 95％， and most preferably more than about 98％of the palladium contained in the palladium-containing solid. In other words， the ashed palladium-containing catalyst C4 may be ground before contact with the first removal composition.

The apparatus for the process of the third aspect comprises， consists of， or consists essentially of a furnace module， a containing means for the dissolution/solubilization of palladium， liquid-solid separation means， and optionally at least one rinse container， wherein the removal apparatus is capable of removing palladium from palladium-containing catalyst C4. The ashed palladium-containing catalyst C4 may have been ground prior to contacting with the first removal composition. The apparatus can further comprise at least one of： a first removal composition container in liquid communication with the containing means for the dissolution/solubilization of palladium； at least one rinse liquid container in liquid communication with the at least one rinse container； at least one centrifuge； agitation means in at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one pump； heating/cooling means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； at least one air input for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； real-time sampling and adjustment； programmable logic controllers or equivalent thereof； sensing means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container； and ventilation means for at least one of the containing means for the dissolution/solubilization of palladium and/or the at least one rinse container. Preferably， the apparatus is designed such that the palladium-containing catalyst C4， whether batch or otherwise， can move from furnace to container to container， automatically or manually， using a moving means. The furnace and containers of the apparatus can be operated in series with one another， with or without intervening parts.

It should be appreciated by the person skilled in the art that the first composition of the first aspect may be the same as or different from the first composition of the third aspect.

The processes are capable of maximizing the efficiency of precious metal， e.g.， palladium， removal. The processes ensure that the palladium-containing catalyst C4 is processed to ensure a minimization of resources (e.g.， chemicals， energy， hardware， software， footprint of the facility， water) ， a minimization of waste， and a maximization of metal reclaimed. This is accomplished， in part， using at least one programmable logic controller， which can be controlled by a SCADA device. It should be appreciated that depending on the module， the process can be either a wet process， a dry process， a chemical process， a physical process， an electrical process， a mechanical process， or some combination of more than one of the foregoing processes. For example， wet processing includes， but is not limited to， metal removal using chemicals and rinsing， while dry processing includes， but is not limited to， thermal processing (i.e.， heating) ， grinding， and burning. In one embodiment， each module has at least one PLC controlling it. In another embodiment， multiple modules have at least one PLC controlling them. When more than one PLC is present， a SCADA device can be used to control the one or more PLCs. A SCADA device is a computer-based system that monitors and controls industrial， infrastructure and facility-based processes. Although not discussed at length， the process of the third aspect also removes platinum and/or rhodium， when present.

In summary， the embodiments of the third aspect include a process for recycling palladium-containing catalyst material C4， wherein the process comprises， consists of， or consists essentially of：

(a) ashing the palladium-containing catalyst C4 in a furnace module to yield a first solid comprising ash；

(b) optionally grinding the first solid in a milling module；

(d) optionally (i) separating the first solid from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a second solid and a liquid， and (ii) rinsing the solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts， and wherein the process efficiently recovers more than about 90％， preferably more than about 95％， and most preferably more than about 98％of the palladium contained in the palladium-containing catalyst C4. Preferably， the process includes moving the palladium-containing catalyst material within a module automatically or manually， and/or moving the palladium-containing catalyst material from module to module， automatically or manually， using a moving means. The process may be controlled by one or more controlling device including， but not limited to， PLCs that coordinate and regulate one or more automated process steps.

Real-Time Monitoring

To achieve the high precious metal removal and recovery efficiency described herein， the process (es) ， hardware， evolved gas， palladium-containing catalyst material， solids， removal composition， raw materials for removal composition， process composition and rinse liquid， process rinse liquid may be monitored in real-time and the data acquired sent to at least one PLC for analysis and further action as needed. The real-time monitoring can occur in any container， within any of the lines， during any point in a process. For example， chemical reactions wherein a removal composition is used to remove at least one metal from the palladium-containing catalyst material can be monitored whereby real-time sampling occurs and a concentration of one or more components determined. This allows the computer to make adjustments so that the removal composition remains at a steady concentration over time. Alternatively， once a certain concentration is achieved， the chemical reaction may be complete and/or the removal composition may be loaded and/or an endpoint may be reached. Similarly， real-time sampling of rinse liquids can occur， allowing the computer to determine the status of the rinse liquid. Often the pH of a removal composition or a rinse liquid must be adjusted and real-time sampling permits this action. The solids can be sampled in real-time as well. Real-time sampling also ensures that workers and the environment are not at risk by engaging the “kill switch” if some pre-specified threshold is achieved. These are just a few examples of the advantages of real-time monitoring and sampling.

Real-time monitoring can include， but is not limited to： temperature； pressure； liquid and/or gas leak detection； and the monitoring of chemical constituents and/or pH values and/or oxidation reduction potentials and/or end points and/or conductivity in solids and/or liquids during mixing， flow， levels， weight， storage， blending， agitation， reactions， recovery， reuse， feed and bleed， neutralization， buffering， diluting， pH adjustment， loading， NOx suppression， filtration， separation， centrifugation， precipitation， diffusion dialysis， resin-based acid recycle and metals recovery， electrowinning， wastewater treatment， and/or regeneration. The chemical constituents monitored can be raw chemical constituents or compositions comprising at least one chemical constituent. The real-time monitoring can occur in any container in any module， within any of the lines， during any point in a process. Process hardware can be monitored in real-time as well. Any of the gases evolved from any of the reactions can be monitored in real-time. Real-time monitoring and analysis can be in-line， direct， indirect， continuous， scheduled and/or require sample preparation. The sampling can be manual or automatic. The analytical analysis to determine concentration can be manual or automatic. Concentrations can be determined using any “analytical techniques” or “sensing means” known in the art including， but not limited to， pH measurement， atomic absorption spectroscopy， atomic emission spectroscopy， inductively coupled plasma spectroscopy， inductively coupled plasma optical emission spectroscopy， UV-Vis spectrophotometry， UV spectrophotometry， titrations， infrared spectroscopy， temperature-controlled infrared spectroscopy， colorimetry， liquid chromatography， high performance liquid chromatography， refractive index sensor， optical sensors， chemical sensors， electrochemical techniques (e.g.， pulsed cyclic galvanostatic analysis， multi-variate analysis， galvanostatic， potentiodynamic) ， cyclic voltammetry， linear polarization， radio frequency identification， and any other technique known by the skilled artisan to measure chemical concentrations.

The at least one PLC and the SCADA， when present， can be used for at least one of the following： data processing； managing and controlling module (s) ； storing of recipes； blending chemistries； separating materials； data archiving and reporting； controlling computer networks and systems； safety， efficiency， economic， and ecological operations； maintenance； leak detection and containment location and special requirements necessary； sampling and monitoring of a variable； and/or printing production reports.

Furnace Module

Palladium-containing catalyst materials can be processed to increase the efficiency of removal of precious metals. In one embodiment， the palladium-containing catalysts can be sent to a furnace/ashing module to ash the combustible materials， e.g.， carbon， thereby increasing the efficiency of recovery of palladium from the palladium-containing catalyst.

In one embodiment， a furnace module comprises a furnace or some other heating means， and means to control the air input into the furnace. In a further embodiment， the furnace module may operate in a continuous and/or batch mode and comprises a furnace， means to feed and/or load the furnace with palladium-containing catalysts， and means to control the air input into the furnace. The type， size and/or capacity of the furnace can be readily determined by one skilled in the art based on factors including， but not limited to， operating temperature， footprint， throughput， capacity， weight， type of material to be ashed and combinations of the foregoing. The furnace comprises one or more heating elements. Preferably， the heating element is electric and comprises one or more materials including， but not limited to， metal， metal alloys， metal superalloys， ceramics， composites and combinations of the foregoing. More preferably， the heating element comprises one or more alloy materials including， but not limited to， Inconel， Monel， Hastelloy， Incoloy Waspaloy， Rene， Haynes， MP98T， TMS， CMSX and combinations of the foregoing. Examples of useful furnaces include， but are not limited to， top loading furnaces， bottom loading furnaces， front loading furnaces， continuous furnaces， bench furnaces， batch furnaces， truck in furnaces， box furnaces， belt furnace， shelf furnaces， truck in furnaces， elevator furnaces， tunnel furnaces， bell furnaces， pusher furnaces， tube furnaces， shaker furnaces and combinations of the foregoing. The furnace may comprise fixed and/or adjustable parameters that may operate manually or automatically including， but not limited to， throughput， weight， capacity， temperature， temperature ramp rate， time， air flow， pressure， ventilation and combinations of the foregoing.

In an embodiment， the furnace includes means to control the air input into the furnace because the furnace ashes the palladium-containing catalysts at high temperatures， e.g.， in a range from about 500℃ to about 800℃， preferably about 600℃ to about 700℃. For example， the furnace may require a supply of air provided at a known minimum airflow. The furnace may comprise means to control the direction， rate and/or flow of air through the furnace including， but not limited to， one or more blowers， fans， dampers， ducts， air curtains， air guides， baffles and combinations of the foregoing. Further， pressure sensors， flow sensors， gas sensors (e.g.， O₂ sensor) ， and/or temperature sensors can be included to control and regulate one or more components in the effluent. The furnace may further comprise means to introduce hydrogen gas at a known minimum air flow. Since palladium is easily oxidized， and the palladium oxide is more difficult to recover using chemical means， palladium-containing catalyst material that is ashed in air， e.g.， to remove combustible materials， may be burned in hydrogen gas to remove the oxide layer (s) . For example， in one embodiment， the palladium- containing catalyst4 can be introduced to a furnace in the presence of air at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours， optionally but preferably followed by the introduction of hydrogen gas at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours.

The furnace preferably includes a ventilation and/or abatement system to handle combustible gases and any ash material that may become airborne. In one embodiment， the ventilation system can or may include an electrostatic precipitator or some filtering system. Further， the furnace shall be in compliance with local fire and air quality codes.

The means to feed the furnace with palladium-containing catalyst material may be automatic or manual and may include at least one of the moving means described herein. Further， the palladium-containing catalyst material may be fed individually or in one or more batches into the furnace. Batches of palladium-containing catalyst material may be formed in the furnace as the palladium-containing catalyst material are fed into the furnace. The palladium-containing catalyst material may be fed into the furnace on one or more support surfaces that support the individual or batch of palladium-containing catalyst material or the palladium-containing catalyst material may be fed onto one or more support surfaces already in the furnace. “Support surfaces” include， but are not limited to， racks， shelves， trays， containers and combinations of the foregoing. Preferably， the palladium-containing catalyst material are arranged on one or more trays having a base surface and a sidewall having a height that extends above the base surface. Further the one or more trays may be solid and/or perforated. The height of the tray sidewall is selected so as to maximize the efficiency of the ashing process and may be selected based on one or more process parameters including but not limited to weight， capacity， temperature， time， air flow， pressure， ventilation and combinations of the foregoing. In one embodiment， the tray sidewall height is from between about 1 mm and about 15 cm. Preferably， the furnace is a batch furnace that includes one or more racks and can accommodate one or more trays. The palladium-containing catalyst material are manually or automatically placed on/in the trays and the trays can be manually or automatically loaded in the furnace. The furnace and trays should be constructed from a material that will withstand the temperatures， pressures， and VOCs of the ashing process and will not be a source of contamination during the heating/cooling processes.

The furnace can be cooled to ambient temperatures following ashing， either with the assistance of refrigeration， the introduction of air to the furnace， by uncontrolled cooling to ambient temperature， or any other means of cooling， as understood by the person skilled in the art.

Preferably， the furnace module ashes the palladium-containing catalyst material based on at least one process recipe that is based on one or more parameters that may be manually or automatically input including， but not limited to， throughput， weight of catalyst material， capacity of the furnace， temperature， temperature ramp rate， cycle time， air flow， pressure， ventilation and combinations of the foregoing， Preferably the process recipe is selected by a PLC that controls one or more functions of the furnace module to ash greater than 80％， preferably greater than 95％， of the ashable content of the palladium-containing catalyst material. In one embodiment， the process recipe includes a programmable temperature/time profile that is based on one or more of type， weight and amount of palladium-containing catalyst material to be ashed. The temperature/time profile for the furnace process may include， but is not limited to， preheating， the rate of continuous temperature ramping， ramp/hold， the rate of stepped temperature ramping， the rate of staged temperature ramping， and combinations of the foregoing.

The material remaining following processing in the furnace module can be sent to further processing to extract palladium from the material or can be sent to a grinding or milling module， or eventually both， as readily determinable by the person skilled in the art.

Milling Module

Grinding or milling means can be used to prepare the palladium-containing catalyst materials for further processing. The grinding means include， but are not limited to， an industrial grinder. The milling means include， but are not limited to， a hammermill， a wet ball mill， etc. The palladium-containing catalyst materials or ash comprising the palladium-containing catalyst materials can be introduced to the grinding or milling means and the materials ground into smaller pieces， for example， less than 10 mesh (1.70 mm) ， more preferably less than 20 mesh (0.85 mm) ， and most preferably less than 30 mesh (0.60 mm) . The grinding or milling means should be equipped with a dust recovery system because of the ash that can be stirred up during the grinding or milling process. Preferably the dust recovery system is capable of capturing dust so that it can be collected and processed. In addition， the grinding or milling means preferably includes means to load and unload solids therein， e.g.， containing means and/or moving means. For example， the palladium-containing catalyst material can be loaded into the grinding or milling means using a conveyor or screw feed.

The ground material remaining following processing in the grinding or milling module can be sent to further processing to extract palladium from the material， as readily determinable by the person skilled in the art. The material can be moved to the next module in a container， e.g.， a hopper， automatically or manually， on one or more moving means. It should be appreciated that the palladium-containing catalyst material can arrive at the fab already ground for further processing using the systems and processes described herein.

Processing Removal Comnositions and Rinse Liquids Subsequent to Use

As discussed herein， once a removal composition is loaded， or otherwise no longer useful for metal removal， and/or once a rinse liquid is no longer useful for rinsing， they can be for further processing including， but not limited to， electrowinning， reduction， diffusion dialysis， pH adjustment， cementation， wastewater treatment， resin-based acid recycle and metals recovery， and any combination thereof， depending on the removal composition or rinse liquid， as disclosed hereinabove.

Palladium reclamation means include， but are not limited to palladium electrowinning and/or other chemical palladium reclamation methods such as reduction. With regards to electrowinning， preferably urea， sodium hydroxide， or both is added to a solution comprising palladium that needs to be electrowon. With regards to other chemical palladium reclamation methods， a solution comprising palladium ions can be reacted with about 1 wt％to about 15 wt％ammonium chloride， preferably about 5 wt％to about 12wt％ammonium chloride， and additional nitric acid to form solid PdCl₄ (NH₄) ₂. The PdCl₄ (NH₄) ₂ precipitate can be separated from the liquid and dissolved in hot water at a temperature in a range from about 40℃ to about 60℃ to yield PdCl₄ (NH₄) ₂ in solution. After separation of any solid from the PdCl₄ (NH₄) ₂ solution， ascorbic acid can be combined with the PdCl₄ (NH₄) ₂ solution to yield pure palladium. Preferably， the ratio of weight percent of ascorbic acid to the concentration of palladium in the solution is about 1∶1 to about 1∶10， more preferably about 1∶4 to about 1∶7. Preferably， the palladium reduction process does not require the use of iron powder and/or butyl xanthate.

Advantageously， electrowinning permits the recovery of one metal at a time， depending on the current. It should be appreciated that the current of the electrowinning process can be maintained at a constant current， changed over time， or both. It should also be appreciated that the voltage of the electrowinning process can be maintained at a constant current， constant voltage， changed over time， or all of the above.

First Removal Comoosition

One embodiment of a first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， optionally at least one halide， optionally at least one acid， and optionally at least one solvent. In another embodiment， the first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， at least one halide salt， optionally at least one acid， and optionally at least one solvent. In one embodiment， the first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， at least one halide， at least one acid， and at least one solvent. In one embodiment， the first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， at least one chloride salt， at least one acid， and at least one solvent. In another embodiment， the first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， at least one chloride salt， at least one sulfur-containing acid， and at least one solvent. In still another embodiment， the first removal composition comprises， consists of， or consists essentially of at least one oxidizing agent， at least one alkaline chloride salt， at least one sulfur-containing acid， and at least one solvent. In yet another embodiment， the first removal composition comprises， consists of， or consists essentially of at least one nitrate salt oxidizing agent， at least one alkaline chloride salt， at least one sulfur-containing acid， and at least one solvent. The first removal composition is aqueous in nature and has a pH less than about 2， more preferably less than about 1. The weight percent ratio of the at least one oxidizing agent to at least one acid is in a range from about 0.1∶1 to about 5∶1， preferably about 1∶1 to about 3∶1. The weight percent ratio of the at least one halide to at least one acid is in a range from about 0.1∶1 to about 5∶1， preferably about 0.5∶1 to about 2∶1.

Oxidizing agents are included in the composition to oxidize the metals to be removed into an ionic form and accumulate highly soluble salts of dissolved metals. Oxidizing agents contemplated herein include， but are not limited to， ozone， nitric acid (HNO₃) ， bubbled air， cyclohexylaminosulfonic acid，， hydrogen peroxide (H₂O₂) ， oxone (potassium peroxymonosulfate， 2KHSO₅·KHSO₄·K₂SO₄) ， ammonium polyatomic salts (e.g.， ammonium peroxomonosulfate， ammonium chlorite (NH₄ClO₂) ， ammonium chlorate (NH₄ClO₃) ， ammonium iodate (NH₄IO₃) ， ammonium perborate (NH₄BO₃) ， ammonium perchlorate (NH₄ClO₄) ， ammonium periodate (NH₄IO₃) ， ammonium persulfate ( (NH₄) ₂S₂O₈) ， ammonium hypochlorite (NH₄ClO) ) ， sodium polyatomic salts (e.g.， sodium persulfate (Na₂S₂O₈) ， sodium hypochlorite (NaClO) ) ， potassium polyatomic salts (e.g.， potassium iodate (KIO₃) ， potassium permanganate (KMnO₄) ， potassium persulfate， potassium persulfate (K₂S₂O₈) ， potassium hypochlorite (KClO) ) ， tetramethylammonium polyatomic salts (e.g.， tetramethylammonium chlorite ( (N(CH₃) ₄) ClO₂) ， tetramethylammonium chlorate ( (N (CH₃) ₄) ClO₃) ， tetramethylammonium iodate ( (N(CH₃) ₄) IO₃) ， tetramethylammonium perborate ( (N (CH₃) ₄) BO₃) ， tetramethylammonium perchlorate ( (N(CH₃) ₄) ClO₄) ， tetramethylammonium periodate ( (N (CH₃) ₄) IO₄) ， tetramethylammonium persulfate ( (N(CH₃) ₄) S₂O₈) ， tetramethylammonium nitrate) ， tetrabutylammonium polyatomic salts (e.g.， tetrabutylammonium peroxomonosulfate， tetrabutylammonium nitrate) ， peroxomonosulfuric acid， urea hydrogen peroxide ( (CO (NH₂) ₂) H₂O₂) ， peracetic acid (CH₃ (CO) OOH) ， sodium nitrate， potassium nitrate， ammonium nitrate， and combinations thereof. Most preferably， the oxidizing agent comprises a nitrate ion including， but not limited to， nitric acid， sodium nitrate， potassium nitrate， ammonium nitrate， tetraalkylammonium nitrate， and combinations thereof.

The at least one halide is preferably a chloride-containing compound including， but not limited to， hydrochloric acid， and alkaline chlorides (e.g.， sodium chloride， potassium chloride， rubidium chloride， cesium chloride， magnesium chloride， calcium chloride， strontium chloride， ammonium chloride， quaternary ammonium chloride salts) ， and combinations thereof， with the proviso that the chloride-containing compound cannot include copper chloride， chlorine gas， or a second， different halide. Preferably， the at least one halide comprises an alkaline chloride， even more preferably an alkali metal chloride such as sodium chloride. The at least one halide can also include salts and/or acids comprising bromide and iodide including， but not limited to， sodium bromide， sodium iodide， potassium bromide， potassium iodide， rubidium bromide， rubidium iodide， cesium bromide， cesium iodide， magnesium bromide， magnesium iodide， calcium bromide， calcium iodide， strontium bromide， strontium iodide， ammonium bromide， ammonium iodide， quaternary ammonium bromide salts， and quaternary ammonium bromide salts.

The at least one acid is preferably a sulfur-containing species such as sulfuric acid， sulfate salts (e.g.， sodium sulfate， potassium sulfate， rubidium sulfate， cesium sulfate， magnesium sulfate， calcium sulfate， strontium sulfate， barium sulfate) ， sulfonic acid， sulfonic acid derivatives， and combinations thereof. Sulfonic acid derivatives contemplated include methanesulfonic acid (MSA) ， ethanesulfonic acid， 2-hydroxyethanesulfonic acid， n-propanesulfonic acid， isopropanesulfonic acid， isobutenesulfonic acid， n-butanesulfonic acid， n-octanesulfonic acid) ， benzenesulfonic acid， benzenesulfonic acid derivatives， and combinations thereof. Preferably， the at least one acid comprises sulfuric acid， preferably concentrated sulfuric acid.

In a particularly preferred embodiment， the first removal composition comprises， consists of， or consists essentially of sodium chloride， sulfuric acid or a salt thereof (e.g.， sodium sulfate) ， nitric acid or a salt thereof (i.e.， sodium nitrate) ， and water.

The first removal composition can further comprise at least one complexing agent (e.g.， a noble metal complexing agent) ， at least one buffering agent， at least one corrosion inhibitor， at least one NOx suppressing agent， at least one surfactant， at least one anti-foaming agent， at least one passivating agent， and any combination thereof.

The first removal composition comprises， consists of， or consists essentially of at least one nitrate-containing salt and at least one solvent.

The at least one nitrate-containing salt can include， but is not limited to， nitric acid， sodium nitrate， potassium nitrate， ammonium nitrate， tetraalkylammonium nitrate， and combinations thereof. Preferably， the at least one nitrate-containing salt comprises nitric acid， ammonium nitrate， sodium nitrate， or combinations thereof.

The at least one solvent includes， but is not limited to， water， methanol， ethanol， isopropanol， butanol， pentanol， hexanol， 2-ethyl-l-hexanol， heptanol， octanol， ethylene glycol， propylene glycol， butylene glycol， tetrahydrofurfuryl alcohol (THFA) ， butylene carbonate， ethylene carbonate， propylene carbonate， dipropylene glycol， diethylene glycol monomethyl ether， triethylene glycol monomethyl ether， diethylene glycol monoethyl ether， triethylene glycol monoethyl ether， ethylene glycol monopropyl ether， ethylene glycol monobutyl ether， diethylene glycol monobutyl ether， triethylene glycol monobutyl ether， ethylene glycol monohexyl ether， diethylene glycol monohexyl ether， ethylene glycol phenyl ether， propylene glycol methyl ether， dipropylene glycol methyl ether (DPGME) ， tripropylene glycol methyl ether (TPGME) ， dipropylene glycol dimethyl ether， dipropylene glycol ethyl ether， propylene glycol n-propyl ether， dipropylene glycol n-propyl ether (DPGPE) ， tripropylene glycol n-propyl ether， propylene glycol n-butyl ether， dipropylene glycol n-butyl ether， tripropylene glycol n-butyl ether， propylene glycol phenyl ether， 2， 3-dihydrodecafluoropentane， ethyl perfluorobutylether， methyl perfluorobutylether， alkyl carbonates， alkylene carbonates， 4-methyl-2-pentanol， tetramethylene glycol dimethyl ether， and combinations thereof. Preferably， the at least one solvent comprises water.

Notably， the first removal composition is substantially devoid of aqua regia， chlorine gas， phosgene， sulfides， and adducts of the formula [R， R′dazdt·nXY] .

Second Removal Composition

The second removal composition comprises， consists of， or consists essentially of at least one nitrate-containing salt and at least one solvent.

The at least one solvent includes， but is not limited to， water， methanol， ethanol， isopropanol， butanol， pentanol， hexanol， 2-ethyl-1-hexanol， heptanol， octanol， ethylene glycol， propylene glycol， butylene glycol， tetrahydrofurfuryl alcohol (THFA) ， butylene carbonate， ethylene carbonate， propylene carbonate， dipropylene glycol， diethylene glycol monomethyl ether， triethylene glycol monomethyl ether， diethylene glycol monoethyl ether， triethylene glycol monoethyl ether， ethylene glycol monopropyl ether， ethylene glycol monobutyl ether， diethylene glycol monobutyl ether， triethylene glycol monobutyl ether， ethylene glycol monohexyl ether， diethylene glycol monohexyl ether， ethylene glycol phenyl ether， propylene glycol methyl ether， dipropylene glycol methyl ether (DPGME) ， tripropylene glycol methyl ether (TPGME) ， dipropylene glycol dimethyl ether， dipropylene glycol ethyl ether， propylene glycol n-propyl ether， dipropylene glycol n-propyl ether (DPGPE) ， tripropylene glycol n-propyl ether， propylene glycol n-butyl ether， dipropylene glycol n-butyl ether， tripropylene glycol n-butyl ether， propylene glycol phenyl ether， 2， 3-dihydrodecafluoropentane， ethyl perfluorobutylether， methyl perfluorobutylether， alkyl carbonates， alkylene carbonates， 4-methyl-2-pentanol， tetramethylene glycol dimethyl ether， and combinations thereof. Preferably， the at least one solvent comprises water.

Notably， the second removal composition is substantially devoid of aqua regia， chlorine gas， phosgene， sulfides， and adducts of the formula [R， R′dazdt·nXY] .

Although the invention has been variously disclosed herein with reference to illustrative embodiments and features， it will be appreciated that the embodiments and features described hereinabove are not intended to limit the invention， and that other variations， modifications and other embodiments will suggest themselves to those of ordinary skill in the art， based on the disclosure herein. The invention therefore is to be broadly construed， as encompassing all such variations， modifications and alternative embodiments within the spirit and scope of the claims hereafter set forth.

Claims

A process for recycling palladium-containing catalyst， wherein the process comprises：

(a) optionally one or more of (i) grinding the palladium-containing catalyst in a milling module， (ii) processing the palladium-containing catalyst to remove at least one other chemical species， and/or (iii) crushing the palladium-containing catalyst；

(b) removing palladium from the palladium-containing catalyst using a removal composition；and

(c) optionally (i) separating the palladium-containing catalyst from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a solid and a liquid， and (ii) rinsing the solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts.
The process of claim 1， wherein the palladium-containing catalyst comprises catalytic converter material comprising palladium， manganese， cerium， calcium， aluminum， and magnesium and either platinum or rhodium or both platinum and rhodium.
The process of claim 2， wherein the removal composition is a first removal composition.
The process of claim 1， wherein the palladium-containing catalyst comprises palladium-on-alumina balls comprising aluminum as well as palladium， iron， zinc， and some nickel.
The process of claim 4， wherein the removal composition is a second removal composition.
The process of any of the preceding claims， further comprising grinding the palladium-containing catalyst in a milling module.
The process of any of the preceding claims， further comprising crushing the palladium-containing catalyst.
The process of any of the preceding claims， wherein the palladium is removed from the palladium-containing catalyst using a first removal composition at about 20℃ to about 100℃， preferably about 40℃ to about 80℃， at time in a range from about 1 min to about 200 min， preferably about 30 min to about 90 min.
The process of any of the preceding claims， wherein the ratio of palladium-containing catalyst to first removal composition is about 1∶1 to about 1∶100， preferably about 1∶10 to about 1∶25.
The process of any of the preceding claims， further comprising separating the palladium-containing catalyst from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a solid and a liquid， and rinsing the solid with a first rinse subsequent to separation.
A process for recycling palladium-containing catalyst， wherein the process comprises：

(a) ashing the palladium-containing catalyst in a furnace module to yield a first solid comprising ash；

(b) optionally grinding the first solid in a milling module；

(c) leaching palladium from the first solid using a first removal composition； and

(d) optionally (i) separating the first solid from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a second solid and a liquid， and (ii) rinsing the second solid with a first rinse subsequent to separation，

wherein the processes are positioned and/or operated in series with one another， with or without intervening parts.
The process of claim 11， wherein the palladium-containing catalyst comprises a carbon-based catalyst comprising carbon， palladium， barium， chromium， and manganese.
The process of claims 11 or 12， wherein the ashing of palladium-containing catalyst in a furnace module to yield a first solid comprising ash comprises：

(a) feeding the palladium-containing components into a catalyst； and

(b) heating the palladium-containing catalyst in the furnace in the presence of air at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours； and

(c) optionally， heating the palladium-containing catalyst in the furnace in the presence of hydrogen at temperatures in a range from about 500-700℃ for time in a range from about 2 to about 6 hours.
The process of any of claims 11-13， further comprising grinding the first solid in a milling module.
The process of any of claims 11-14， wherein the palladium is removed from the solid using a first removal composition at about 20℃ to about 100℃， preferably about 40℃ to about 80℃， at time in a range from about 1 min to about 200 min， preferably about 30 min to about 120 min.
The process of any of claims 11-15， wherein the ratio of first solid to first removal composition is about 1∶10 to about 1∶200， preferably about 1∶70 to about 1∶120.
The process of any of the preceding claims， further comprising separating the first solid from the first removal composition using liquid-solid separation means subsequent to palladium removal to yield a second solid and a liquid， and rinsing the solid with a first rinse subsequent to separation.
The process of claims 10 or 17， wherein the liquid is further processed to reclaim palladium， wherein the processing comprises electrowinning and/or chemical reclamation methods.
The process of claim 18， wherein the chemical reclamation method comprises：

(i) contacting a solution comprising palladium ions with ammonium chloride and nitric acid to form solid PdCl₄ (NH₄) ₂；

(ii) separating the PdCl₄ (NH₄) ₂ solid from the liquid；

(iii) dissolving the PdCl₄ (NH₄) ₂ solid in water at a temperature in a range from about 40℃ to about 60℃ to yield PdCl₄ (NH₄) ₂ in solution； and

(iv) combining PdCl₄ (NH₄) ₂ in solution with ascorbic acid to yield solid palladium.
The process of any of the preceding claims， wherein the process further comprises moving palladium-containing catalyst within a module or apparatus automatically or manually， using a moving means.
The process of any of the preceding claims， wherein the process further comprises moving palladium-containing catalyst from module to module and/or within a module， automatically or manually， using a moving means.