Zircon Sand Decomposition via Segmented Thermal Processing

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Solution Overview

Problem

Conventional methods for producing aqueous zirconium chloride solutions face challenges such as low decomposition rate of zircon sand, high impurity content, particularly sodium and iron, and require significant capital investment, leading to inefficiencies and increased costs.

Innovation Solution

The method involves grinding zircon sand to a predetermined particle size, decomposing it in two stages, and adjusting the water washing temperature to enhance decomposition and reduce impurity incorporation, using an iron container for primary decomposition and a stainless-steel container for secondary decomposition, and employing hydrochloric acid washing to minimize impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If heat-melting of zircon sand is performed in an iron container at 600 to 900°C, then decomposition of zircon sand is achieved, but the iron container is severely corroded causing increased iron content in the solution

Engineering Contradiction:
Improvedecomposition rate of zircon sandVSAvoidiron content in solution
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The decomposition process is divided into two separate stages: first in an iron container at lower temperature (400°C or less), then in a stainless-steel container at higher temperature (400 to 1100°C). This segmentation allows the iron container to avoid severe corrosion by not exposing it to both high temperature and prolonged alkali contact simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the temperature parameter for the iron container decomposition step (reducing it to 400°C or less), and introduces a second decomposition step at higher temperature using a corrosion-resistant stainless-steel container. This parameter change resolves the contradiction by decoupling the temperature requirement from the container material limitation.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If conventional water washing is used to remove alkali silicate, then alkali silicate is dissolved and removed, but sodium in sodium zirconate cannot be sufficiently removed causing increased sodium content

Engineering Contradiction:
Improveremoval of alkali silicateVSAvoidsodium content in solution
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

Hydrochloric acid is introduced as an intermediary substance to wash the decomposition product. This acid washing step effectively removes sodium from the zirconium compounds without causing severe corrosion issues, serving as a mediator between the decomposition product and the final solution.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If hydrothermal treatment is performed in an autoclave, then zircon sand decomposition is achieved, but large capital investment is necessary for mass production

Engineering Contradiction:
Improvedecomposition efficiencyVSAvoidcapital investment
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention uses simple, inexpensive containers (iron container followed by stainless-steel container) instead of expensive autoclave equipment. The process achieves effective decomposition using these simpler vessels, eliminating the need for large capital investment in hydrothermal treatment equipment.

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

4Object-affected harmful factors

If ground zircon sand is decomposed in an iron container at 400°C or less, then decomposition is achieved with reduced iron container corrosion, but further decomposition at higher temperature is needed

Engineering Contradiction:
Improveiron container corrosionVSAvoiddecomposition completeness
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The decomposition process is segmented into two distinct stages: first in an iron container at lower temperature (400°C or less) to minimize corrosion, then in a stainless-steel container at higher temperature (400 to 1100°C) to achieve complete decomposition. This segmentation resolves the contradiction by separating the corrosion-protection requirement from the decomposition-completeness requirement.

Inventive Principle:
Principle #1Segmentation

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 approach results in a higher decomposition rate of zircon sand and lower impurity content, reducing production costs and facilitating scalable production facilities, thereby improving the efficiency and purity of the aqueous zirconium chloride solution.

Implementation Method 1

a raw material called 'zircon sand' is heat-melted or hydrothermally treated in the presence of alkali

Methodology Applied
Scientific EffectThermal decomposition: Decomposition (biological)

Implementation Method 2

the concentrate comprising alkali zirconate and zirconium hydrate (ZrO(OH) x ) as main components obtained by the filtration is dissolved in hydrochloric acid

Methodology Applied
Scientific EffectAcid dissolution: Solvation

Implementation Method 3

adding 0.2 to 1.0 g/L of gelatin to coagulate and precipitate gelled silica

Methodology Applied
Scientific EffectGelation: Gel

Data Source

PatentEP3067320B1Method for producing aqueous zirconium chloride solution
Publication Date: 2018.09.19 DAIICHI KIGENSO KAGAKU KOGYO CO LTD
  • EP3067320B1 patent drawingFigure 1
  • EP3067320B1 patent drawingFigure 2
  • EP3067320B1 patent drawingFigure 3~4

AI summary

Provided is a method for producing an aqueous zirconium chloride solution having a higher decomposition rate of zircon sand and a lower impurity content, as compared with conventional methods. The method for producing an aqueous zirconium chloride solution according to the present invention comprises: step 1 of grinding zircon sand to an average particle diameter of 10 µm or less; step 2 of adding a sodium compound to the ground zircon sand to thereby obtain a mixture; step 3 of firing the mixture in an iron container at 400°C or less to thereby obtain a decomposed product; step 4 of firing the decomposed product in a stainless-steel container at 400 to 1,100°C to thereby obtain a fired product; step 5 of dispersing the fired product in water to prepare a dispersion, and washing the fired product with water while adjusting the temperature of the dispersion to 70°C or less, thereby obtaining a water-washed cake; step 6 of washing the water-washed cake with hydrochloric acid with a pH of 1 to 6 to thereby obtain zirconium hydrate; and step 7 of dissolving the zirconium hydrate in hydrochloric acid, and then removing insoluble components to thereby obtain a salt solution.