Is the phosphorus sludge in yellow phosphorus production wastewater considered hazardous waste?
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A large amount of phosphorus sludge is generated in the wastewater from yellow phosphorus production. Is this phosphorus sludge considered hazardous waste? If so, which category of hazardous waste does it fall into? Phosphorus sludge is one of the main by-products produced during the production of yellow phosphorus, and it constitutes hazardous solid waste in the phosphorus chemicals industry. The treatment and utilization of sludge phosphorus is a very important issue in yellow phosphorus production. It not only affects the phosphorus recovery rate and production costs in this industry, but more seriously, it causes severe environmental pollution problems. Sludge phosphorus is a harmful substance containing P_4 that is formed during the phosphorus production process; it consists of elemental phosphorus, dust impurities, and water. This post was last edited by Welcome on 2009-4-6 09:15]
Are there really no friends in this forum who work in yellow phosphorus production or phosphate salt production?
When producing yellow phosphorus in electric furnaces, some amount of phosphorus sludge is inevitably generated, especially in furnaces that do not have electrostatic precipitators; 10%–15% of the yellow phosphorus produced ends up mixed with this sludge. The production of 1 ton of yellow phosphorus results in more than 500 kg of phosphorus sludge. Due to the different origins of the raw ore used, the elemental phosphorus content in the sludge phosphorus varies as well. The sludge in the sewage sedimentation tank also contains a small amount of elemental phosphorus. Currently, there are various methods for treating phosphorus-rich sludge in China, but the vast majority of these are used to produce phosphoric acid from such sludge. In silicon fertilizer manufacturing plants, a small amount of this phosphorus-rich sludge is mixed with phosphorus slag, and air oxidation is used to convert it into usable P2O5, thereby reducing the need to treat the phosphorus-rich sludge.
The main methods for extracting yellow phosphorus from sludge phosphate at home and abroad include: phosphorus vaporization method, chemical reagent method, vacuum filtration method, electric field treatment method, adsorption separation method, etc. However, due to the respective disadvantages and problems of these methods, their application in the treatment of sludge phosphate is limited. At present, the phosphorus vaporization method is the most widely studied approach for extracting yellow phosphorus from sludge phosphate in China; yet it has drawbacks such as a short lifespan of the phosphorus vaporization equipment, severe environmental pollution, a relatively low phosphorus recovery rate, and low economic efficiency