Hengfeng A1545 Optimizes Sedimentation‑Clarification Performance for a Sand‑Washing Plant in Minas Gerais, Brazil
A large sand‑washing plant located in Minas Gerais, Brazil, was confronted with inefficient solid‑liquid separation for mineral‑rich wastewater. The raw wastewater contained massive fine quartz particles, clay and silt fractions. The previously adopted polymer produced fragile flocs, slow sedimentation rate, high supernatant turbidity, heavy polymer consumption and limited water recycling efficiency, which increased fresh‑water intake and operational expenditure.
After site investigation and laboratory jar‑testing, Hengfeng recommended Anionic Polyacrylamide A1545 together with targeted process tuning, delivering remarkable improvement in floc formation, settling performance and water reuse capacity.
Site Overview
Industry: Sand washing & aggregate processing
Location: Minas Gerais, Brazil
Wastewater treatment capacity: Approximately 1 800 m³/day
Slurry output: 45‑55 tons/day (wet mineral slurry)
Wastewater Characteristics
- Total Suspended Solids (TSS): 3 200‑4 100 mg/L
- Turbidity: 780‑920 NTU
- pH: 7.4‑8.2
- Dominant contaminants: Fine quartz, clay and silt particles; high‑content inorganic suspended solids
Initial Challenges
Before optimization, the plant suffered the following operational difficulties. The supernatant turbidity after settling stayed between 115‑140 NTU. The polymer dosage reached 28‑32 g/t dry solids, while the complete sedimentation time took 18‑22 minutes. Formed flocs were fragile and easily broken under hydraulic shear. The water recycling rate was only 68%, leading to high fresh‑water consumption. Frequent sediment pond dredging also brought considerable maintenance costs to the facility.
Hengfeng Solution
Hengfeng proposed Anionic Polyacrylamide A1545, featuring ultra‑high molecular weight, moderate anionic charge density and outstanding adsorption‑bridging capability for inorganic mineral suspensions.
To maximize the polymer performance, Hengfeng also optimized key operational parameters. The polymer preparation concentration was adjusted to 0.12%, and the maturation aging time was controlled at 45 minutes. The optimized polymer dosage was reduced to 19‑22 g/t dry solids. The polymer injection point was relocated right before the settling tank inlet, and mixing intensity was reduced accordingly to preserve floc integrity and avoid floc breakage.
Performance Results
After continuous field commissioning and stable running, the plant achieved obvious performance gains.
Supernatant turbidity dropped from the original 115‑140 NTU down to 18‑24 NTU. Polymer dosage decreased from 28‑32 g/t DS to 19‑22 g/t DS, representing an overall polymer consumption reduction of 31%. The complete sedimentation time was shortened significantly from 18‑22 minutes to 7‑9 minutes. The water recycling rate rose from 68% up to 92%. With improved settling efficiency, pond dredging frequency was reduced by 42%.
The optimized scheme greatly cut fresh‑water demand, lowered chemical consumption and settling‑pond maintenance workload, while securing stable long‑term operation.
Project Outcome
By combining Hengfeng A1545 anionic polyacrylamide with on‑site process adjustment, the sand‑washing facility realized faster sedimentation, much clearer recycled water, decreased polymer consumption and higher water reuse efficiency. The clarified overflow water satisfies on‑site production reuse requirements and eases local environmental‑compliance pressure.
Hengfeng Commitment
At Jiangsu Hengfeng Fine Chemical Co., Ltd., we deliver not only high‑quality polyacrylamide products, but also complete wastewater treatment solutions including product screening, laboratory testing, on‑site technical support and process parameter optimization.
With Hengfeng A1545, sand‑washing and mineral‑processing plants can achieve superior solid‑liquid separation, lower operating costs and consistent long‑term system performance.
