Method for purifying low-temperature low-turbidity seawater by magnetic-sand-loaded flocculation

Abstract

The invention relates to a method for purifying low-temperature low-turbidity seawater by magnetic-sand-loaded flocculation, which comprises the following steps: (1) mixing stage: a coagulating agent FeCl3 is added into seawater entering a mixing basin, and quick stirring is performed at the velocity gradient G of 620-700 s<-1> for 1-2 minutes; (2) flocculation stage: the seawater containing the coagulating agent FeCl3 enters a flocculation basin, and magnetic sand is added into the flocculation basin to perform loaded flocculation; and (3) precipitation stage: the flocculated seawater containing magnetic sand enters a precipitating basin to precipitate, effluent water is collected from the purified seawater, the magnetic-sand-loaded flocculating constituent precipitates to the basin bottom, sludge on the basin bottom is sucked by a sand pump into a hydrocyclone, the magnetic sand with higher specific gravity slides down along the hydroclone wall and reenters the flocculation basin via a connecting pipe, and the sludge with lower specific gravity is discharged along with the water flow, thereby separating the flocculating constituent from the magnetic sand. The magnetic-sand-loaded flocculation technique is utilized to increase the condensation cores, and the adsorption actions of the static electricity and magnetic field are utilized to form the compact composite magnetic flocculating constituent, thereby improving the flocculation effect of the low-temperature low-turbidity seawater.

Description

Technical field: [0001] The invention belongs to the field of seawater purification, and in particular relates to a method for purifying low-temperature and low-turbidity seawater by flocculating and loading magnetic sand. Background technique: [0002] Low temperature and low turbidity seawater has always been a difficult point in seawater desalination pretreatment. The main reasons for affecting the coagulation effect are: the low temperature causes the specific gravity and viscosity of seawater to increase, and the thermal movement of impurity molecules in the water slows down, which is not conducive to the hydrolysis of the coagulant, and the formation of alum flowers is difficult and difficult to sink; while the impurity concentration in low turbid seawater Smaller, the probability of collision between particles is reduced, which is not conducive to flocculation reaction. [0003] In the coagulation process, the formation of coagulation core is one of the key control s...

AI Technical Summary

Problems solved by technology

The main reasons for affecting the coagulation effect are: low temperature leads to an increase in the specific gravity and viscosity of seawater, slowing down the thermal movement of impurity molecules in the water, which is not conducive to the hydrolysis of the coagulant, and it is difficult to form alum flowers and sink; while the impurity concentration in low turbid seawater Smaller, the probability of collision between particles is reduced, which is not conducive to flocculation reaction

Images