Nitrous Effluent Calcination Anti-Sticking Additives

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Solution Overview

Problem

The calcination of aqueous nitric liquid effluents containing metal or metalloid nitrates often results in sticky oxides that clog calcination tubes, and the use of aluminum nitrate as a dilution adjuvant increases glass production and limits waste load rates during vitrification, requiring cumbersome optimization of calcination conditions.

Innovation Solution

A process using a dilution adjuvant comprising aluminum nitrate and at least one other nitrate, such as iron nitrate or rare earth nitrates, to prevent calcinate sticking and minimize glass production, allowing for effective calcination without clogging and increased waste load rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminum nitrate is added as a dilution adjuvant to prevent sticking, then calcination can be performed without clogging, but the quantity of glass to be produced increases and waste load rate is limited

Engineering Contradiction:
Improvecalcination process reliabilityVSAvoidglass production quantity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention changes the chemical composition parameters of the dilution adjuvant by replacing aluminum nitrate with iron nitrate and/or rare earth nitrates. This parameter change modifies the properties of the resulting oxide to prevent sticking while avoiding the excessive glass production associated with aluminum nitrate

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses alternative nitrates (iron nitrate, rare earth nitrates) that serve the temporary function of preventing sticking during calcination but do not permanently increase glass production requirements, effectively replacing the less desirable aluminum nitrate

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If aluminum nitrate is added to prevent sticking, then calcination can proceed without clogging, but the aluminum content in glass increases production temperature requirements and limits waste load rate

Engineering Contradiction:
Improvecalcination process reliabilityVSAvoidglass production temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention changes the chemical composition parameters by substituting aluminum-based adjuvant with iron and/or rare earth nitrate-based adjuvants. This changes the thermal properties of the glass matrix, avoiding the temperature increase and waste load rate limitations caused by high aluminum content

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If aluminum nitrate is used as dilution adjuvant, then sticking is prevented, but the quantity of glass to be produced increases

Engineering Contradiction:
Improvecalcination operation easeVSAvoidglass production quantity
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The invention modifies the chemical parameters of the dilution adjuvant from aluminum nitrate to iron nitrate and/or rare earth nitrates, maintaining the anti-sticking operational ease while reducing the quantity of glass that needs to be produced

Inventive Principle:
Principle #35Parameter changes

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

The use of iron and rare earth nitrates in the dilution adjuvant effectively prevents calcinate sticking and clogging while reducing the quantity of glass produced, enhancing waste load rates and simplifying glass formulation constraints compared to aluminum nitrate alone.

Implementation Method 1

a step of calcining the effluent to transform the metal or metalloid nitrates into their oxides

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

a dilution adjuvant leading during calcination to a non-sticky oxide being added to the effluent prior to the calcination step

Methodology Applied
Scientific EffectOxide formation: Oxidation

Implementation Method 3

a vitrification step by dissolution in a glass of confinement of the calcinate produced during the calcination stage

Methodology Applied
Scientific EffectVitrification: Vitrification

Data Source

PatentEP2374136B1Method for processing a nitrous aqueous liquid effluent by calcination and vitrification
Publication Date: 2012.11.14 AREVA NC

AI summary

The invention relates to a method for processing a nitrous aqueous liquid effluent containing nitrates of metals or metalloids, including a step of calcinating the effluent in order to convert the metal or metalloid nitrates into metal or metalloid oxides, at least one compound selected from the metal or metalloid nitrates and the other compounds of the effluent resulting in a sticky oxide upon calcination, and a dilution additive resulting in a non-sticky oxide upon calcination being added to the effluent prior to the calcination step, wherein the dilution additive includes aluminium nitrate and at least one nitrate selected from iron nitrate and rare earth nitrates.