Metal Recovery from Waste Molybdic Catalysts via Oxidizing Acid Leaching

Solution Overview

Problem

Conventional methods for recycling metals from waste catalysts, such as those used in the oil-refining industry, are inefficient due to high energy consumption, contamination by sulfur or sulfides, and the difficulty in recycling nickel and cobalt, leading to environmental pollution and low recycling rates.

Innovation Solution

A method involving leaching waste molybdic catalysts in a highly oxidized acid to dissolve and oxidize metals, followed by refining to extract metallic oxides, which reduces contamination, energy use, and improves recycling efficiency, while avoiding the negative effects of aluminum and sulfur.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional high-temperature roasting (950-1050°C) is used to extract metals from waste catalysts, then metal extraction can be achieved, but energy consumption increases significantly and sulfur/sulfide contamination worsens

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent changes the chemical parameters of the extraction process by using oxidizing acids (nitric acid, sulfuric acid, or their mixtures) instead of conventional high-temperature roasting. The acid concentration and oxidation potential are adjusted to achieve effective metal dissolution at ambient or moderate temperatures, thereby reducing energy consumption while maintaining extraction efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal-mechanical roasting process with a chemical dissolution process using oxidizing acids. Instead of relying on high temperature and mechanical agitation, the solution uses chemical oxidation and dissolution mechanisms to extract metals, fundamentally changing the extraction mechanism from thermal to chemical

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Quantity of substance

If high-temperature roasting is applied to waste catalysts, then metals can be extracted, but sulfur and sulfides diffuse and cause serious environmental pollution

Engineering Contradiction:

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the temperature parameter from high (950-1050°C) to ambient or moderate conditions, and changes the chemical environment from oxidative heating to controlled acid dissolution. This prevents sulfur/sulfide volatilization and diffusion while effectively extracting metals through chemical dissolution, thereby eliminating sulfur pollution

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful sulfur-containing compounds in waste catalysts into beneficial soluble sulfate forms through oxidation by the acid solution. The sulfur that would otherwise be a pollutant is transformed into soluble species that remain in the leachate, allowing for complete metal extraction without environmental release of sulfur

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If conventional roasting methods are used, then processing can proceed, but nickel and cobalt are difficult to recycle, reducing overall recycling efficiency

Engineering Contradiction:

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent uses oxidizing acid solutions that can simultaneously dissolve and extract multiple metal types (molybdenum, nickel, cobalt, vanadium, and other base metals) from the waste catalyst matrix. This multi-functional extraction approach treats all metals uniformly, eliminating the need for separate processing steps for different metal types and significantly improving overall recycling efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively recycles metals like vanadium, molybdenum, and nickel with high efficiency and quality, reducing environmental pollution and the cost of the recycling process, achieving recycling rates of over 99% with minimal sulfur contamination.

Implementation Method 1

metals in the waste molybdic catalyst are dissolved and oxidized by the acid to obtain a first solution and dregs

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

leaching, by soaking a waste molybdic catalyst into a highly oxidized acid

Methodology Applied

Scientific EffectLeaching: Solvation

Implementation Method 3

the vaporizer obtained from the step of leaching is converted into highly oxidized acid and recycled in the step of leaching

Methodology Applied

Scientific EffectPhase change: Phase Change

Data Source

PatentUS8657917B2Method for recycling metals from waste molybdic catalysts

Publication Date: 2014.02.25

AI summary

A method for recycling metals from waste molybdic catalysts, comprises steps of leaching, by soaking a waste molybdic catalyst into a highly oxidized acid and conducting a reaction between sulfur in the waste molybdic catalyst and the acid to obtain sulfide and vaporizer, wherein metals in the waste molybdic catalyst are dissolved and oxidized by the acid to obtain a first solution and dregs; and refining, by further dissolving metals in the dregs into a second solution, and extracting metals in the waste molybdic catalyst from the first and second solution; wherein, the vaporizer obtained from the step of leaching is converted into highly oxidized acid and recycled in the step of leaching.