Spent Molybdenum Catalyst
Spent catalysts are a valuable source of molybdenum. They are derived from the oxidation of clinically unsaturated hydrocarbons. They are often formed as by-product streams in the chemical processing industry. Therefore, it is important to recover these valuable metals and dispose of them safely and economically.
Recovering molybdenum from spent catalysts is environmentally friendly and can be a profitable venture for the industry. There are a number of existing recovery processes. However, they require extensive processing equipment and expensive chemical reagents. Thus, the present invention provides a simple, efficient and economical method for recovering molybdenum constituents from spent catalysts.
The present invention is particularly effective for recovering molybdenum from organic solutions of spent catalysts. This process is especially suitable for achieving molybdenum recovery from spent catalysts that contain less than 2% molybdenum. A high extraction capacity also characterizes it.
In order to improve the effectiveness of the process, supplemental reagents can be used. These can include 10%-30% ammonium hydroxide.
An aqueous extractant is added intermittently to the organic solution of spent molybdenum catalyst. The aqueous extractant may consist of water, soluble reagents or both. As a result of the interaction between the extractant and the organic solution, the molybdenum in the spent catalyst can be separated from the organic phase.
The molybdenum can be recovered in the form of ammonium molybdenum compounds or in the air. This product can be calcined and transformed into molybdenum oxides.
Recovery of vanadium from spent catalyst residues
In order to recover vanadium from spent molybdenum catalyst residues, a novel process was developed. This process comprises a leaching step to remove the molybdenum from the unsupported spent hydroprocessing catalysts, followed by solvent extraction to extract the metals. The concentrations and temperature of the leaching solutions were optimized for complete extraction.
Spent HDS catalysts contain a variety of important metals and are considered hazardous industrial wastes. Several methods have been proposed for recovering the metals from these spent catalysts. However, they vary considerably in terms of recovery rates. Therefore, these methods need to be adapted to specific industrial conditions.
An initial study was performed to determine the effect of the roasting time and temperature on the leaching of spent HDS catalysts. It was found that a roasting time of 140 minutes is sufficient for the removal of more than 80% of vanadium.
A further increase in roasting time did not increase the recovery. However, an increased caustic soda concentration did lead to a proportional increase in V recovery. Likewise, an increase in the organic-to-aqueous ratio produced a more complete extraction.
In addition, it was found that the amount of time required for vanadium precipitation was not affected by temperature change. Similarly, the precipitation of molybdenum did not increase when the temperature was increased.
Alternative sources of metal recovery
A spent catalyst is a solid waste which is generated due to petroleum refining. It is an important secondary industrial resource which can be retrieved by several processes.
There are many different sources of metal recovery from spent catalysts. The most commonly used process is the hydrometallurgical route. However, this method requires more energy and is more expensive than other processes. Another option is the biotechnological route.
One method is to use the two-stage roasting and water-leaching procedure. This procedure enables a high recovery of molybdenum and vanadium. Mo and V are widely used in preparing various types of steel.
In this study, three different roasting and leaching parameters were evaluated: temperature, time, and the amount of soda ash added. Results showed that roasting was the most energy-consuming step.
In addition, the addition of soda ash had an impact on the leaching of molybdenum. It was found that a 20 wt.% addition was the optimum value. Moreover, the initial concentration of Co-Mo catalyst was analyzed. After leaching, the molybdenum concentration was compared with the initial concentration in the spent catalyst.
The elemental analysis showed some fractions of sulfur and carbon in the catalyst. To isolate the sulfides, a carbon disulfide was used.
Working Across The Globe
London Chemicals & Resources Ltd (LCR) is an international distributor, stockist and supplier of industrial inorganic chemicals. We hold several agencies and serve a global customer base both directly and via a network of local agents. LCR is committed to providing efficient service and competitive pricing to all customers.
Working closely with several producer principals around the world, quality, consistency and reliability are all important watchwords for LCR ensuring that our customers return again and again.
Raw materials are supplied for a wide range of applications including battery, catalyst, ceramic, fertiliser, glass, plating, refinery, superalloy and other industries. Our materials are usually packed in drums or bags in accordance with UN, CLP and other applicable local and international regulations.
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Our experienced, friendly and knowledgeable staff at LCR are familiar with relevant legislation, transport procedures and documentation including REACH, SDSs and ADR.
To view our safety data sheet relating to vanadium pentoxide powder, please click here.
Who Are We?
London Chemicals & Resources Ltd (LCR) operates globally, processing non-ferrous metal-containing secondaries and distributing a range of metal salts and alloys which, in many cases, are recycled from these secondaries.
We hold exclusive agencies from Full Yield Industry Co Limited based in Taiwan and AGR-CR based in Spain. LCR source more than 90% of the spent catalysts and other feedstocks processed at Full Yield and represent them exclusively for sales of vanadium, molybdenum and nickel chemicals.
We also represent a completely new processing plant; AGR-CR treating spent catalysts and other secondaries and scheduled to start commercial operations in Q1, 2020. LCR offers commercially competitive recycling options with an emphasis on environmentally sound management. Our experienced, friendly and knowledgeable staff are familiar with relevant legislation, transport procedures and documentation including trans-frontier notifications; REACH, SDSs and ADR. Quality, consistency and reliability are all important watchwords for LCR ensuring that our customers return again and again.
We are regularly purchasing and recycling secondaries containing cobalt, copper, molybdenum, nickel, tungsten, vanadium and zinc found typically in boiler ashes and slags, catalysts spent – unused or out of date, drosses, dusts, filter cakes, furnace dust, galvanic solution residues, grindings and grinding sludges, metallics, shavings, metal powders, picking solutions, plating sludges, production wastes, residues, skimmings, sludges, wastewater treatment residues.
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