Industrial Wastewater and Waste Salts
Industrial wastewater and waste salts are among the main hazardous wastes generated during the production processes of industries such as chemical, pharmaceutical, printing and dyeing, and electroplating. They are complex in composition and difficult to dispose of; improper dumping or discharge can severely pollute soil and water bodies. Tianli has deep expertise in the resource utilization of industrial wastewater and waste salts. We employ MVR evaporation crystallization and fluidized bed drying as our core processes to achieve the reduction, harmlessness, and resource recovery of waste salts. Leveraging our comprehensive technological advantages, we transform waste salts into recyclable industrial raw materials, supporting enterprises' green and low-carbon development and fulfilling their environmental responsibilities.
I. Core Properties of Industrial Wastewater and Waste Salts
Industrial wastewater and waste salts are mostly mixed crystalline powders, mainly composed of soluble salts such as sodium chloride, sodium sulfate, and ammonium chloride, and also containing small amounts of organic matter, heavy metal ions, and other impurities. They appear as white or pale yellow powders, are highly hygroscopic, easily clump together, and have poor storage stability. Their solubility varies with temperature depending on the composition, but generally follows the dissolution rules of soluble salts. This characteristic is the core basis for the MVR evaporation crystallization process design. Waste salts are relatively stable at room temperature and easily separate from water upon heating. After purification, impurities can be removed, transforming them into regenerated salts that meet industrial standards, achieving resource recovery, solving environmental problems, and improving resource utilization.
II. Detailed Explanation of Core Process Sections
(I) MVR evaporation crystallization process: high-efficiency separation and resource-based purification
The MVR (Mechanical Vapor Recompression) evaporation and crystallization section is the core of waste salt resource utilization. Its main purpose is to separate salts from water through efficient evaporation and precise crystallization of industrial wastewater and waste salt solutions, while simultaneously removing some impurities to obtain crude waste salt, laying the foundation for subsequent drying and purification. Our company uses a forced circulation MVR evaporation and crystallization system, adapted to the complex composition and scaling characteristics of waste salt, achieving efficient separation and energy-saving disposal.
The process follows the core logic of pretreatment of feed liquid - MVR evaporation - crystallization separation - mother liquor circulation: Industrial wastewater and waste salt feed liquid are first filtered, purified, and deoiled to remove suspended impurities and organic matter, preventing scale buildup on the equipment. The pretreated feed liquid enters a forced circulation evaporator, where a steam compressor pressurizes and heats the secondary steam generated during evaporation, circulating it as a heat source without requiring large amounts of live steam. The evaporator operates under negative pressure to control the temperature, and the feed liquid circulates at high speed, preventing localized overheating and scaling. Continuous evaporation of water causes the feed liquid to reach a supersaturated state, which is then sent to a crystallizer to precipitate waste salt crystals. After centrifugal separation, wet waste salt is obtained, and the mother liquor is returned to the evaporation system for recycling, achieving zero wastewater discharge and full salt recovery.
(II) Fluidized bed drying section: efficient dehydration and stable molding
The fluidized bed drying section handles the wet mixed salts after MVR evaporation and crystallization. Its core task is to remove free water from the crystal surface, ensuring that the moisture content meets the standards for industrial recycled salt, guaranteeing that the crystals are intact and free of lumps, facilitating subsequent purification, packaging, and recycling, and improving the market adaptability of the recycled salt.
Tianli uses fluidized bed dryer, which is well-suited to the hygroscopic and easily agglomerated characteristics of waste salts. Wet salts are evenly fed into the dryer via a sealed feeder. Hot air is pressurized in the air distribution chamber , causing the material to suspend and fluidize. The material continuously tumbles, ensuring uniform drying. Fluidized bed drying is highly efficient, quickly removing moisture while preventing overheating and deterioration of the salts. The dried salts are cooled and sieved to obtain regenerated salt. Dust-laden gas undergoes two-stage dust removal treatment before being discharged in compliance with standards, achieving clean production.
III. Core Technological Advantages
1. Technological Advantages: the process is mature and stable, capable of handling waste salts of different compositions and concentrations, and adaptable to diverse industrial wastewater treatment needs . The MVR evaporation crystallization process, combined with a forced circulation system, effectively solves the problems of easy scaling and complex composition of waste salt liquid, resulting in high separation efficiency; the fluidized bed dryer is suitable for the characteristics of waste salts, ensuring good drying uniformity and convenient equipment operation and maintenance.
2. Energy consumption advantages: MVR evaporation technology fully recovers and utilizes secondary steam, with a steam latent heat recovery rate of over 90%, and power consumption of only 30-45 kWh per ton of water, saving more than 55% energy compared to traditional multi-effect evaporation; fluidized bed drying adopts hot air circulation recovery technology to reduce heat loss, and the overall energy consumption is reduced by 30% compared to traditional treatment processes, significantly reducing the environmental treatment costs for enterprises.
3. Environmental advantages: the entire process adopts a closed-loop design, with mother liquor recycling to achieve zero discharge of industrial wastewater; the evaporation and drying processes are operated in a closed manner, coupled with a two-stage dust removal system, the dust emission concentration is lower than the industry standard, no harmful gases are generated, effectively solving the problem of waste salt pollution, which is in line with the concept of green and low-carbon development and meets environmental emission requirements.
4. Product advantages: by precisely controlling the evaporation, crystallization and drying parameters, waste salt can be converted into regenerated salt with a purity of ≥98%. The crystals are uniform in size and free of lumps. After further purification, it can be recycled in the chemical, building materials and other fields, realizing the resource utilization of waste salt, turning waste into treasure, and improving the enterprise's resource utilization rate and economic benefits.
5. Control advantages: equipped with a fully automatic PLC control system, it can monitor key parameters such as feed concentration, evaporation temperature, and drying moisture in real time, realize precise control of the process flow, facilitate operation, reduce manual intervention, reduce human error, ensure stable treatment process, and ensure uniform quality of recycled salt products.
We solve environmental problems with technology and promote resource recycling with expertise. Based on the characteristics of industrial wastewater and waste salt materials, our company has deeply cultivated core technologies of MVR evaporation crystallization and fluidized bed drying. With comprehensive advantages in technology, energy consumption, and environmental protection, we provide one-stop solutions for the resource-based disposal of waste salts for various industries, helping enterprises achieve environmental compliance and resource recycling, and jointly building a green industrial ecosystem.