Industrial Waste Salt Purification via Multi-Effect Crystallization
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Solution Overview
Problem
Current methods for treating industrial waste salt are inefficient in removing organic matter and impurities, resulting in low-quality by-products that are often landfilled, leading to environmental pollution and resource wastage.
Innovation Solution
A method involving sequential steps of dissolving, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption and oxidation decolorization, and multi-effect evaporative crystallization to produce high-purity sodium sulfate, sodium chloride, and sodium nitrate crystals, with controlled crystallization temperatures to achieve industrial-grade standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If direct landfill treatment is used for waste salt, then disposal is simple and quick, but environmental pollution risk increases and resources are wasted
Solution Approach 1:
The patent converts harmful waste salt containing organic matter and heavy metals into valuable resources by extracting and purifying sodium chloride, sodium sulfate, and sodium nitrate. The harmful components are transformed into beneficial products that can be reused in industry, thereby eliminating environmental pollution risks while recovering resources.
Solution Approach 2:
Instead of discarding waste salt through landfill, the patent recovers valuable salt components through a multi-step purification process. The waste salt is dissolved, purified to remove impurities, and then crystallized to recover high-purity sodium chloride, sodium sulfate, and sodium nitrate for industrial reuse.
2Loss of substance
If recycling disposal methods (dissolving and refining, thermal incineration, carbonization) are used, then resource recovery is attempted, but organic matter removal rate is low and product quality is poor
Solution Approach 1:
The patent segments the waste salt treatment process into distinct stages: dissolution, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption, oxidation decolorization, and multi-effect evaporative crystallization. Each stage targets specific impurities, progressively improving product purity while maintaining resource recovery.
Solution Approach 2:
The patent employs parameter changes throughout the process, including pH adjustment during chemical pre-purification, temperature control during evaporation and crystallization, and concentration variations during different purification stages. These parameter changes optimize the removal of organic matter and heavy metals while preserving salt components.
3Use of energy by moving object
If multi-effect evaporative crystallization is used, then energy efficiency is improved, but scaling and corrosion problems occur and only mixed salt is produced
Solution Approach 1:
The patent performs preliminary purification actions before multi-effect evaporative crystallization. Chemical pre-purification removes scaling and corrosive substances, and deep purification eliminates impurities that would interfere with the crystallization process. This preliminary action prevents scaling and corrosion during evaporation while maintaining energy efficiency.
Solution Approach 2:
The patent introduces intermediary purification steps between dissolution and crystallization. These intermediary processes include chemical pre-purification with pH adjustment, deep purification through filtration and adsorption, and oxidation decolorization. These intermediaries protect the evaporation system from scaling and corrosion while enabling production of pure separated salts.
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 effectively removes organic matter and impurities, producing salts that meet industrial standards, reducing environmental pollution and resource wastage, and enabling the effective utilization of treated industrial waste salt.
Implementation Method 1
the industrial waste salt is sequentially subject to dissolving
Implementation Method 2
performing a precipitation reaction treatment of industrial high-concentration salt-water
Implementation Method 3
performing an ion exchange treatment of the clarified effluent obtained in step (1)
Implementation Method 4
performing multi-effect evaporative crystallization of the final produced water
Implementation Method 5
performing multi-effect evaporative crystallization of the final produced water so as to produce the salt
Implementation Method 6
performing oxidation of the decolorized effluent obtained in step (4) to remove the organic matter through oxidation
Data Source
AI summary
An industrial waste salt resourceful treatment method comprises the following steps: the industrial waste salt is sequentially subject to dissolving, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption and oxidation decolorization and multi-effect evaporative crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; the crystallization temperature of sodium sulfate is in a range of 75° C. to 85° C.; the crystallization temperature of sodium chloride is in a range of 60 to 70° C.; and the crystallization temperature of sodium nitrate is in a range of 45° C. to 55° C. An industrial waste salt resourceful treatment device is further provided.