Treatment method and system for purifying permeate from phosphogypsum storage yard

Abstract

The invention discloses a treatment method and system for purifying leachate from a phosphogypsum stockyard and a treatment system for purifying leachate from a phosphogypsum stockpile is used for the treatment, which is carried out in the following steps: (1) introducing the leachate from a phosphogypsum stockpile into In the primary neutralization tank, add quicklime or slaked lime, control the pH of the neutralization tank, add flocculant, and then pump it into the primary settling tank; (2) introduce the clarified liquid from the top of the primary settling tank into the secondary neutralization tank, Add quicklime, slaked lime or sodium hydroxide to adjust the pH, then add flocculant, and then pump into the secondary settling tank; (3) pump the secondary clarified liquid into the membrane treatment unit; (4) process the treated liquid in step (3) The permeate is pumped into the biochemical treatment unit to complete the treatment process. The treatment method provided by the invention has good effect and low cost, so that all indicators of the treated permeate can reach the first-level standard of the "Comprehensive Sewage Discharge Standard" (8978‑1996).

Description

technical field [0001] The invention relates to the technical field of chemical sewage treatment, in particular to a treatment method and system for purifying permeate from a phosphogypsum storage yard. Background technique [0002] Phosphogypsum is the waste residue discharged by phosphorus chemical enterprises. Prepare 1 ton of phosphoric acid (with 100% P 2 o 5 total) to produce 4.8-5.0 tons of phosphogypsum (dry basis). At present, the world's output of phosphogypsum has exceeded 280 million tons, and my country's output has exceeded 50 million tons. Any discharge will cause environmental pollution. Most enterprises use open-air storage yards to stack them. Phosphogypsum is a moist fine powder, 95% of the particles are smaller than 0.2mm, the free water content is 20% to 30%, and it contains a small amount of harmful impurities such as phosphorus, fluorine, organic matter and silicon dioxide. It is acidic and its pH value is generally below 4.5. . Long-term stockpil...

AI Technical Summary

Problems solved by technology

However, with the development of the enterprise, due to various factors, the permeate cannot be reused or cannot be fully used, and it will face the problem of discharging the permeate after it is technically treated to meet the standard.

Images