Description

Project Overview

This project was designed for the treatment of high-salinity wastewater generated from a gold metallurgy process. The wastewater contained high concentrations of sodium chloride and sodium sulfate, with a solids content of approximately 25 wt%. In addition to the demanding crystallization conditions, the project site had limited installation space, requiring a compact and efficient system design.

ENCHEM developed a double-effect central circulation evaporation and crystallization system to meet these challenges. Compared with conventional evaporation systems, the central circulation design features a smaller footprint and lower overall equipment height, making it particularly suitable for facilities with restricted installation space while maintaining high processing efficiency and operational reliability.

Process Solution    

The metallurgy effluent is concentrated in the double-effect central circulation evaporator until it reaches a supersaturated state, where salt crystals begin to form. The resulting slurry is then transferred to a centrifuge for solid-liquid separation. The recovered salt crystals are collected for further handling, while the mother liquor is recycled back to the evaporator for continued concentration, maximizing resource recovery and minimizing wastewater discharge.

The entire process is designed for continuous operation, providing stable performance and high treatment efficiency for high-salinity industrial wastewater.

Key Features

• Compact system design

with a reduced footprint and lower equipment height, ideal for sites with limited installation space.

• Double-effect evaporation technology

significantly reduces steam consumption compared with single-effect systems.

• Central circulation design

ensures uniform slurry circulation and stable crystallization performance.

• Forced circulation pumps

prevent crystal settling and caking, reducing the risk of tube blockage while minimizing scaling on heat transfer surfaces.

• High operational reliability

allowing extended continuous operation with reduced maintenance and cleaning frequency.

• Integrated heat recovery system

improves overall energy efficiency by recovering heat from condensate.

• PLC-based automatic control system

enables stable operation, real-time monitoring, and simplified plant management.

System Configuration

The complete evaporation system typically includes:

•  Double-effect central circulation evaporators

•  Central circulation heaters

•  Forced circulation pumps

•  Vacuum system and condenser

•  Centrifuge for solid-liquor separation and with mother liquor recycling system

•  Condensate heat recovery system

•  PLC automatic control system

Applications

The double-effect central circulation evaporator is widely used for the treatment of high-salinity wastewater and crystallization processes in industries such as:

•   Gold and non-ferrous metal metallurgy

•   Mining wastewater treatment

•   Chemical processing

•   Salt recovery and zero liquid discharge (ZLD) systems

•   Industrial wastewater treatment

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