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Desen high-efficiency soaking modules blend chemical or biological solvents into the slurry. A lifting mixer and adjustable-speed classification keep reagents in contact with contaminant particles, improving reaction efficiency while preventing the slurry from settling.

2. Multistage Classification and Dewatering

Hydrocyclones separate fine fractions, and coarse sand is dewatered by spiral classifiers so it can be reused. Fine slurry moves to a deep cone thickener and filter press, producing a dry cake for off-site disposal.

3. Water Treatment and Closed-Loop Reuse

Process water passes through inclined tube settling and staged reaction tanks with dosing, mixing and aeration before being recycled, achieving a reuse rate of 90 percent or more.

Field Evidence from Real Remediation Projects

Desen has applied enhanced washing on challenging sites across China. A mobile washing truck carried out ex-situ chemical washing for arsenic-contaminated soil in Beijing, while a Guangzhou plant treated arsenic, mercury, nickel and lead at 60 t/h. The former Hangzhou Steel site was remediated with a chemical washing train at 30 t/h, and a smaller Hangzhou project treated chemically contaminated soil at 10 m3/h. These projects confirm that a well-designed reagent scheme can bring heavy metals below acceptance criteria even on difficult clay-rich soils.

Choosing a Chemical Washing Partner

• Demand process validation: confirm reagent selection and dosage through a laboratory test before mobilisation
• Verify the water balance: a strong plant recycles most of its process water and limits waste
• Check mobility: skid-mounted and truck-mounted systems allow fast relocation between dispersed plots
• Review discharge compliance: treated water and filter cake must meet local regulatory standards

While physical scrubbing liberates contaminants, chemistry closes the gap to compliance. Combined in a properly engineered system, the two create a versatile and cost-effective route for heavy metal and organic contamination.