Photocatalytically Active Clinker via Calcium Titanate Formation

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Solution Overview

Problem

The existing methods for producing photocatalytically active clinker and cement face challenges in utilizing titanium dioxide effectively, as they rely heavily on the anatase form, which is difficult to select and procure, and are limited by the origin and anatase content of the titanium dioxide used.

Innovation Solution

A method involving the reaction of TiO2-containing materials with clinker raw meal to form calcium titanates, such as CaTiO3, during the clinker production process, allowing for the use of titanium dioxide from various sources and converting it into photocatalytically active species like CaTiO3, which can be introduced directly or separately into the rotary kiln and burned at high temperatures, enabling the production of photocatalytically active clinker and cement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If titanium dioxide is used as photocatalytic material, then photocatalytic activity is achieved, but the selection and procurement of suitable titanium dioxide becomes problematic due to dependency on anatase form

Engineering Contradiction:
Improvephotocatalytic activityVSAvoidselection and procurement of titanium dioxide
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the chemical form of titanium dioxide from anatase to calcium titanate (CaTiO3) through reaction with calcium oxide in the clinker production process. This parameter change eliminates the need to select specific anatase forms, as the calcium titanate form is automatically produced during clinker manufacturing regardless of the original titanium dioxide source.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses calcium oxide (lime) as an intermediary substance that reacts with titanium dioxide to form calcium titanate. This intermediary enables the conversion of various titanium dioxide forms into the photocatalytically active calcium titanate form, bridging the gap between raw material selection and final photocatalytic function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If anatase proportion is increased to enhance photocatalytic effect, then photocatalytic activity improves, but the complexity of selecting and procuring titanium dioxide increases

Engineering Contradiction:
Improvephotocatalytic effectVSAvoidselection and procurement process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the target parameter from anatase proportion to calcium titanate content. By specifying calcium titanate content (e.g., 4-10 wt.%) in the clinker rather than requiring high anatase proportions in the input titanium dioxide, the selection and procurement process is simplified while maintaining photocatalytic effectiveness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The clinker production process itself serves to convert the titanium dioxide into photocatalytically active calcium titanate. The existing thermal and chemical conditions in the clinker kiln automatically facilitate the formation of calcium titanate, eliminating the need for separate anatase selection or conversion processes.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If titanium dioxide is introduced directly into clinker production, then production cost decreases, but mixing difficulty increases when titanium dioxide is in powder form

Engineering Contradiction:
Improveproduction costVSAvoidmixing with raw meal
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The rotary kiln's existing mixing and heating functions serve dual purposes: mixing the titanium dioxide-containing materials with the raw meal and simultaneously converting the titanium dioxide into calcium titanate through thermal reaction. This eliminates the need for separate mixing operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The titanium dioxide-containing materials are introduced into the rotary kiln where they will be converted to calcium titanate during the clinker burning process. This preliminary introduction allows the materials to be processed along with the raw meal through the existing kiln infrastructure, avoiding additional mixing equipment or steps.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If firing temperature is increased to convert titanium dioxide to calcium titanate, then photocatalytic activity improves, but energy consumption increases

Engineering Contradiction:
Improveconversion to calcium titanateVSAvoidfiring temperature
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The high-temperature clinker production process serves multiple functions simultaneously: it produces the clinker cementitious material, converts titanium dioxide to calcium titanate, and provides the thermal energy needed for both processes. The same thermal field performs multiple purposes, avoiding additional energy input requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the titanium dioxide conversion process with the existing clinker production process. The calcium titanate formation reaction occurs within the same kiln system during the same heating cycle, combining two processes into one integrated operation rather than requiring separate treatment.

Inventive Principle:
Principle #5Merging (Combining)

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 enables the production of cost-effective photocatalytically active clinker and cement with enhanced photocatalytic activity, using waste materials like paint sludge and spent catalysts, and maintains the physical integrity and setting properties of the clinker, allowing for the use of calcium titanates like CaTiO3, which demonstrates outstanding photocatalytic properties.

Implementation Method 1

materials containing TiO2 are reacted with clinker raw meal or raw mix to form calcium titanates, in particular CaTiO3

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

firing takes place at temperatures above 1250°C, preferably at 1350°C and particularly preferably at 1450°C

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

the TiO2-containing materials are fed into a rotary kiln together with the clinker raw mix and burned

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

photocatalysis means reactions in which a catalyst is brought into an excited state under the action of light of a suitable wavelength, in which state the catalysis of various degradation reactions of different organic molecules can take place

Methodology Applied
Scientific EffectPhotocatalysis: Photo-oxidation

Data Source

PatentEP2367769B1Method for producing photocatalytically active clinker
Publication Date: 2017.10.11 HOLCIM TECHNOLOGY LTD

AI summary

In a method for producing photocatalytically active clinker, materials containing TiO2 are reacted with raw ground clinker or raw mixture to form calcium titanates, in particular CaTiO3.