Spent Catalyst Metal Recovery via Low-Temperature Alkaline Leaching
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Solution Overview
Problem
Conventional methods for recovering valuable metals from spent catalysts in oil refining and petrochemical processes require high temperature and high pressure, leading to environmental pollution and economic losses due to the generation of harmful gases and excessive energy consumption, and are unable to recover metals like aluminum and nickel effectively.
Innovation Solution
A method involving a leaching step at less than 100°C under normal pressure using a sodium hydroxide solution to extract VO3− compounds from spent catalysts, followed by a precipitation step with ammonium chloride, which allows for the recovery of vanadium, molybdenum, aluminum, and nickel without producing harmful gases or liquid waste, and eliminates the need for high-temperature heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high temperature and high pressure processes are used to remove sulfur and leach metal compounds from spent catalysts, then sulfur removal and metal recovery are achieved, but harmful gases such as sulfur dioxide are generated causing environmental pollution and excessive energy costs are incurred
Solution Approach 1:
The patent changes the temperature parameter from high temperature (conventional roasting) to low temperature (below 100°C leaching), and changes the chemical environment by using alkaline solutions instead of oxidative roasting conditions. This parameter change allows sulfur removal and metal leaching to occur under mild conditions without generating harmful sulfur dioxide gases, thus resolving the contradiction between effective sulfur removal and harmful gas generation
Solution Approach 2:
The patent introduces an alkaline leaching solution as an intermediary medium to facilitate sulfur removal and metal extraction. Instead of using high temperature oxidative conditions that produce harmful gases, the alkaline solution acts as a gentle mediator that dissolves sulfur compounds and metal compounds from the spent catalyst under mild conditions, achieving the same goal without environmental pollution
2Quantity of substance
If high temperature and high pressure processes are used to remove sulfur and leach metal compounds from spent catalysts, then sulfur removal and metal recovery are achieved, but excessive energy costs are incurred
Solution Approach 1:
The patent fundamentally changes the temperature parameter from high temperature (conventional roasting requiring hundreds of degrees Celsius) to low temperature (leaching process below 100°C). This parameter change dramatically reduces the energy input required for the process while maintaining effective sulfur removal and metal recovery, thus resolving the contradiction between sulfur removal efficiency and energy cost
3Quantity of substance
If high temperature processes are used to recover metals from spent catalysts, then sulfur removal is achieved, but metals such as aluminum, nickel, and cobalt cannot be recovered and are discarded as industrial waste
Solution Approach 1:
The patent uses an alkaline leaching solution as an intermediary that selectively dissolves metal compounds from the spent catalyst without requiring high temperature conditions. This gentle chemical environment preserves the integrity of metal compounds containing aluminum, nickel, and cobalt, allowing them to be leached into the solution and subsequently recovered, thus resolving the contradiction between sulfur removal and metal recovery
Solution Approach 2:
The patent changes the temperature parameter from high temperature (which causes metal compound degradation) to low temperature (below 100°C leaching). This parameter change prevents the decomposition of metal compounds during the sulfur removal process, enabling simultaneous recovery of sulfur and valuable metals like aluminum, nickel, and cobalt, thus resolving the contradiction between sulfur removal and metal recovery
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method significantly reduces environmental pollution and energy costs by recovering valuable metals with high recovery rates without generating SOx or liquid waste, and enables the recovery of metals like aluminum and nickel that were previously discarded.
Implementation Method 1
a leaching step in which a first inorganic compound containing VO3− is leached from the spent catalyst at a temperature of less than 100° C. under normal pressure
Implementation Method 2
a precipitation step in which a second inorganic compound containing VO3− is precipitated by addition of a salt to the first inorganic compound leached out in the leaching step
Data Source
AI summary
A method for recovering valuable metals is disclosed. The method includes: a spent catalyst preparation step in which a spent catalyst is prepared; and a leaching step in which a first inorganic compound containing VO3− is leached from the spent catalyst at a temperature of less than 100° C. under normal pressure.