Industrial Dust Thermal Treatment for Volatile Constituent Removal
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Solution Overview
Problem
Existing methods are inefficient and energy-intensive for removing volatile constituents from industrial dusts, limiting the substitution rate of secondary zinc oxide in the primary zinc industry and requiring costly disposal of residues.
Innovation Solution
A method involving rapid heating of industrial dust to 600°C or more, followed by thermal treatment at 900°C to 1200°C under controlled oxidizing conditions to remove volatile constituents, such as halogens and metals, while concentrating valuable materials like zinc oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rolling method is used to process industrial dust, then zinc oxide can be recovered, but volatile constituents (halogens, lead) cannot be effectively removed, limiting substitution rate to 10-15%
Solution Approach 1:
The patent applies parameter changes by modifying the thermal treatment parameters - heating to 600°C or more and maintaining temperature for at least 30 minutes. This temperature and time parameter change enables effective removal of volatile constituents (halogens, lead) while preserving zinc oxide, thereby resolving the contradiction between substitution rate and harmful volatile constituents.
Solution Approach 2:
The patent employs controlled oxidizing conditions during thermal treatment, introducing oxygen to accelerate the oxidation and volatilization of harmful constituents like lead and halogens. This strong oxidizing environment selectively removes volatile contaminants while maintaining zinc oxide integrity, increasing substitution rate from 10-15% to potentially 100%.
2Object-affected harmful factors
If thermal treatment at 900-1200°C is applied to remove volatile constituents, then halogen and lead removal efficiency increases, but energy consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-heating the industrial dust to 600°C before the main thermal treatment phase. This preliminary heating step begins the volatilization process early, reducing the total energy required for the subsequent high-temperature treatment at 900-1200°C, while still achieving effective removal of halogens and lead.
Solution Approach 2:
The patent maintains continuous thermal treatment at elevated temperatures for at least 30 minutes, ensuring complete removal of volatile constituents without requiring repeated heating cycles. This continuous action optimizes energy efficiency by maintaining a steady thermal state rather than repeated heating and cooling, reducing overall energy consumption while achieving thorough contaminant removal.
3Object-affected harmful factors
If rapid heating to 600°C or more is applied, then volatile constituents are effectively removed, but process time increases
Solution Approach 1:
The patent optimizes the time-temperature parameters by heating to 600°C or more and maintaining this temperature for at least 30 minutes. This parameter optimization achieves effective volatile constituent removal while minimizing process time, balancing treatment effectiveness with production efficiency.
4Quantity of substance
If industrial dust with high iron content is processed, then zinc oxide can be recovered, but iron residues must be stored with high costs and environmental requirements
Solution Approach 1:
The patent employs a flexible approach by applying thermal treatment that selectively volatilizes iron compounds while preserving zinc oxide. This creates a flexible separation mechanism where iron residues are converted to volatile forms and removed, leaving behind high-purity zinc oxide product and eliminating the need for costly iron residue storage and disposal.
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 efficiently reduces volatile constituents by up to 95% and concentrates valuable materials, providing a more resource-saving and environmentally friendly alternative for recycling industrial dusts, enabling their use as high-quality raw materials.
Implementation Method 1
Under the process temperatures which are prevailing there, chlorine and fluor volatilize as compounds with lead, potassium, or sodium, and collect with other volatile elements, such as cadmium oxide and mainly zinc oxide in the dust
Implementation Method 2
processing the industrial dust by the (preheated) heating device, wherein processing comprises: iia) (extremely rapidly) heating the industrial dust
Implementation Method 3
Due to the high oxygen affinity of gaseous zinc, an immediate exothermic re-oxidation of the Zn to ZnO occurs in the exhaust gas system
Data Source
AI summary
A product and method for producing a valuable material product from industrial dust having the steps of providing the industrial dust, which has at least one valuable material and a first concentration of volatile constituents, to a heating device with an operating temperature of 600° C. or more, preparing the industrial dust by means of the heating device, wherein the preparation comprises heating the industrial dust at a rate of 20° C./min or more, thermally treating the industrial dust by means of the heating device at a treatment temperature in the range from 900° C. to 1200° C., in particular in the range from 1000° C. to 1100° C., for 30 minutes or more, and controlling and/or regulating the oxidizing conditions during the preparation, wherein the preparation comprises at least partially removing the volatile constituents from the industrial dust, and providing the valuable material product.