Ilmenite Processing With Closed-Loop Titanium and Iron Recovery
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Solution Overview
Problem
Existing methods for processing ilmenite concentrate to produce titanium-containing products generate significant amounts of waste and require high-cost materials, posing environmental and economic challenges.
Innovation Solution
A method involving the digestion of ilmenite concentrate with hydrochloric acid, followed by countercurrent processing stages to produce titanium oxychloride, which is then hydrolyzed and calcined, with by-products like iron hydroxides and calcium chloride being recycled, and hydrogen chloride regenerated, resulting in high-value products with zero waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sulfate method is used to process ilmenite concentrate, then titanium dioxide product is obtained, but large amounts of ferrous sulfate heptahydrate and acidic wastewater are generated
Solution Approach 1:
The patent changes the chemical parameters of the digestion process by using hydrochloric acid instead of sulfuric acid, and controlling the Fe2+/Ti4+ ratio in the digestate. This parameter change transforms the waste products from ferrous sulfate to calcium chloride and ammonia, which can be readily recycled, thereby resolving the waste generation problem while maintaining titanium dioxide product quality
Solution Approach 2:
The patent implements a recovery system where calcium chloride from the digestion process is converted to calcium carbonate and recycled back as a neutralizing agent, and ammonia is recovered from the hydrolysis step and reused. This closed-loop recovery eliminates waste discharge and reduces raw material consumption
2Manufacturing precision
If chloride method is used to process ilmenite concentrate, then titanium dioxide product is obtained, but high requirements for process safety and iron chlorides waste are generated
Solution Approach 1:
The patent fundamentally changes the chemical environment from chloride-based to sulfate-free acidic conditions using hydrochloric acid digestion followed by hydrolysis. This parameter change eliminates the need for chlorine gas handling and high-temperature chlorination steps, thereby removing the safety hazards while maintaining product quality through controlled hydrolysis and calcination
Solution Approach 2:
The patent extracts and separates iron from the titanium-containing stream during the digestion and hydrolysis processes. Iron is precipitated as iron hydroxide or converted to iron oxide, which can be removed as a valuable pigment byproduct, thereby eliminating iron chlorides waste and improving process safety
3Reliability
If additional steps are added to make slag or synthetic rutile from ilmenite, then feedstock for chloride method is obtained, but production costs increase and waste is generated
Solution Approach 1:
The patent segments the processing into distinct functional stages: digestion with hydrochloric acid, separation of iron and titanium components, hydrolysis of titanium oxychloride, and calcination. This segmentation allows each stage to be optimized independently and enables the direct processing of ilmenite concentrate without requiring intermediate slag or synthetic rutile production, thereby reducing cost and complexity
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 method achieves high titanium extraction efficiency, reduces production costs, and minimizes waste generation, making it environmentally friendly and economically efficient.
Implementation Method 1
digestion of ilmenite concentrate with hydrochloric acid to obtain a solution of titanium oxychloride and iron chlorides
Implementation Method 2
hydrolysis of titanium oxychloride to obtain a precipitate of titanium oxides/hydroxides
Implementation Method 3
calcination of the precipitate to obtain a pigment based on titanium dioxide
Implementation Method 4
oxidation of iron hydroxides with ambient oxygen to produce iron oxide pigments
Implementation Method 5
regeneration of hydrogen chloride from ammonium chloride solution
Data Source
AI summary
The present invention relates to the processing of natural titanium-containing feedstock, mainly ilmenite concentrate, including ilmenite ores with a low TiO2 content, into products with high added value without generating any liquid or solid waste. The method according to the invention comprises the following stages: digesting ilmenite concentrate, processing the solid residue following ilmenite concentrate digestion, hydrolysis of titanium oxychloride, washing titanium oxides/hydroxides precipitate from impurities, calcination of titanium oxides/hydroxides precipitate, precipitation of iron hydroxides to obtain black, red and yellow iron oxide pigments, processing the mother liquor containing calcium chloride, regeneration of hydrogen chloride from ammonium chloride solution, obtaining ammonium sulfate and ammonium sulfate crystallization, obtaining crystalline ammonium chloride. The resulting products are pigments, pigment fillers, mineral fertilizers, construction materials, raw materials for the production of metals, and other products; they are used in various fields of application such as paint and coatings industry, pulp and paper industry, in the production of plastics, in metallurgy, in agricultural, construction industries and others.