Two-Zone Fluidized Bed for Partial Roasting Copper Gold Ores
Solution Overview
Problem
Conventional partial roasting methods for copper, nickel, and gold ores face challenges with sintering due to hotspots and inadequate heat transfer, leading to increased inert material content and high investment costs, which complicates the removal of arsenic and antimony sulfides and affects the purity of the final product.
Innovation Solution
A fluidized bed reactor design with two distinct zones, where at least 60 wt-% of inert particles are in the first zone and at least 60 wt-% of ore particles are in the second zone, utilizing a fluidizing gas to maintain temperatures between 500 and 850°C, and adjusting particle sizes and densities to minimize sintering and reduce inert material usage, allowing for efficient arsenic removal without additional sand content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional partial roasting methods are used to remove arsenic and antimony sulfides, then the arsenic content is reduced, but sintering occurs due to hotspots and inadequate heat transfer
Solution Approach 1:
The fluidized bed is divided into two distinct zones: a first zone (lower section) where inert particles are concentrated to absorb heat and prevent hotspots, and a second zone (upper section) where ore particles are concentrated for efficient roasting. This spatial segmentation allows simultaneous arsenic removal and sintering prevention by distributing thermal energy across different regions.
Solution Approach 2:
Inert particles act as an intermediary substance in the first zone, serving as a heat sink to absorb excess thermal energy generated during sulfur oxidation. These inert particles prevent direct heat concentration on ore particles, thereby eliminating the formation of hotspots that cause sintering, while still allowing the roasting process to proceed effectively in the second zone.
2Reliability
If additional inert material is added to prevent sintering, then sintering is reduced, but the inert material content in the final product increases
Solution Approach 1:
By segmenting the fluidized bed into two zones with different particle compositions, the system concentrates inert particles in the first zone and ore particles in the second zone. This segmentation allows the inert particles to perform their heat-absorbing function without being mixed with and contaminating the final roasted ore product, thus preventing sintering while maintaining product purity.
Solution Approach 2:
The system extracts and separates the function of sintering prevention from the final product by confining inert particles to the first zone. The inert particles are taken out from the product stream and used solely as a thermal management medium in the lower zone, while the roasted ore from the second zone is free of excessive inert material contamination.
3Use of energy by moving object
If high fluidization gas velocity is used to maintain temperature, then heating efficiency is improved, but hotspots are formed leading to sintering
Solution Approach 1:
The system segments the thermal management function by dedicating the first zone to heat absorption through inert particles and the second zone to efficient heating of ore particles. This segmentation allows high fluidization gas velocity to be used in the second zone for efficient heating without creating hotspots, as any excess heat is absorbed by the inert particles in the first zone.
Solution Approach 2:
The inert particles in the first zone serve as a thermal intermediary that buffers the system against excessive heating. They absorb surplus thermal energy that would otherwise create hotspots, allowing high fluidization gas velocities to be used for efficient heating while maintaining temperature uniformity and preventing sintering.
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 effectively prevents sintering during operation and shutdowns, maintains low inert material content, and achieves high-purity ore with reduced arsenic content below 0.3 wt-%, enhancing the efficiency and cost-effectiveness of the roasting process.
Implementation Method 1
the ore particles are heated in the presence of inert particles to a temperature between 500 and 850°C in a fluidized bed
Implementation Method 2
heating with the addition of oxygen
Implementation Method 3
Sulfur oxidation may occur in ways that include the oxidation of sulfur gas and the oxidation of gaseous or solid sulfides
Implementation Method 4
The bulk of the energy generation comes from sulfur oxidation, however further reactions are exothermic
Implementation Method 5
the ore particles are heated in the presence of inert particles to a temperature between 500 and 850°C in a fluidized bed
Data Source
Figure 1~2
AI summary
The above mentioned invention describes a process for removing arsenic and/or antimony sulfides from copper, nickel and/or gold containing ore particles. Ore particles are fed into a reactor, wherein a fluidizing gas is injected into the reactor to form a fluidized bed containing at least a portion of the ore particles. The ore particles are heated in the presence of inert particles to a temperature between 500 and 850 °C and are withdrawn from the reactor. At least 60 wt-% of the inert particles form a first zone of the fluidized bed and at least 60 wt-% of the ore particles form a second zone above the first zone.