Phosphate Salt Production via Acid Digestion and Impurity Removal
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Solution Overview
Problem
Phosphate salts used in agriculture and food industry often contain high levels of radioactive and heavy metal impurities, leading to environmental pollution and health risks due to their use in fertilizers and food production, as current methods fail to effectively reduce these contaminants.
Innovation Solution
A phosphate salt with reduced content of radioactive elements and heavy metals is produced through a wet and non-thermal process involving digestion of phosphate ore with hydrochloric acid, followed by separation and neutralization at controlled temperatures between 50° C and 70° C, allowing for the precipitation of phosphate ions with minimized impurity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If phosphate ore is used as a source for phosphate salts, then phosphorus supply for agriculture is achieved, but radioactive and heavy metal impurities contaminate the soil and food chain
Solution Approach 1:
The patent applies extraction by selectively dissolving phosphate minerals from ore using sulfuric acid or phosphoric acid, separating phosphorus from radioactive and heavy metal impurities that remain in the solid residue. This allows phosphorus to be extracted for agricultural use while leaving contaminants behind.
Solution Approach 2:
The patent changes chemical parameters by controlling acid concentration, temperature, and reaction time during the digestion process to optimize phosphorus dissolution while minimizing the solubility and co-dissolution of radioactive and heavy metal impurities, thereby purifying the phosphate product.
2Productivity
If conventional phosphate production methods are used, then phosphate salts are produced efficiently, but impurity removal is insufficient
Solution Approach 1:
The patent segments the purification process into multiple stages: initial acid digestion to dissolve phosphates, filtration to remove insoluble residues, and additional treatment steps to remove dissolved impurities. This multi-stage approach achieves high purity while maintaining productivity.
Solution Approach 2:
The patent uses an intermediary substance (acid solution) to facilitate the separation of phosphorus from impurities. The acid acts as a mediator that selectively dissolves phosphate minerals while leaving radioactive and heavy metal contaminants in the solid phase, enabling efficient purification.
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 resulting phosphate salt has significantly lower levels of radioactive and metallic impurities, making it suitable for use in agricultural and food compositions, reducing contamination risks and enabling the use of low-grade phosphate sources, while maintaining a rapid and economically viable production process.
Implementation Method 1
a phosphate source digestion using a first aqueous solution of hydrochloric acid, with formation of an attack liquor consisting of an aqueous phase comprising phosphate ions and chloride ions in solution, and a first insoluble solid phase containing impurities
Implementation Method 2
a neutralisation of said aqueous phase comprising phosphate ions and chloride ions in solution at a pH sufficient to form an aqueous medium comprising chloride ions and to precipitate the phosphate ions in the form of said phosphate salt
Data Source
AI summary
A source of phosphate for agriculture and food industry comprises a phosphate salt in solid form of formula Mn(HPO4)y.zH2O in which M is Na, K, NH4, n=2, and y=1; or M is Ca, n=1, y=1; or M is Al or Fe, n=2, y=3; and in which z is 0, 1 or 2, wherein said phosphate salt has a phosphate content expressed as a P2O5 content of between 30 and 50% by weight of the phosphate salt, and it has a cadmium content lower than 0.40 ppm.