The method of desalination of sea sand

2022-08-30

The presence of salt in sea sand will cause it to induce chloride ions that corrode steel bars when it is used, which will cause harm to the durability of concrete. Therefore, sea sand needs to be desalinated before it can be used as sand for concrete in the construction industry.

mechanical wash sea sand

The mechanical method processes the sea sand through multiple processes such as classification machinery, water supply and drainage equipment, and centrifugal equipment. Each process has corresponding standards to ensure the desalination quality of the sea sand. Its advantages are that it takes less time, the quality can be guaranteed, it can work in a narrow range, it can be industrially mechanized, and it is suitable for emergency treatment of sea sand and other special situations; More than 1.5t of fresh water is consumed per 1m? of sea sand desalinated.

In the world, my country is not a country with abundant water resources. It is one of the countries with the most scarce water resources per capita in the world. The per capita freshwater resources are only about 25% of the world average. Therefore, if the sea sand desalination process requires a large amount of fresh water, it is very unfavorable for the protection of precious fresh water resources in my country, and does not meet the requirements of sustainable development.

Moreover, the mechanical method uses mechanical equipment for desalination of sea sand. The special washing equipment required is expensive, and the investment required in the early stage is large. When the desalination market of sea sand is chaotic, and even some enterprises still use sea sand indiscriminately, this method It is difficult to develop in the market.

fresh water flushing

The fresh water flushing method includes bucket filtering method and bulk water method. The bucket type water filtering method can be operated on a narrow site, and each 1m? of sea sand needs to consume 0.8t of fresh water, and the desalination time of each batch of sand is 12-24h. The scattered water method requires a large site, but the water consumption is small, the fresh water consumption per 1 m? of sand is more than 0.2t, and the desalination time of each batch of sand is more than 12h. It is similar to the mechanical method, but with reduced mechanical steps.

Compared with the mechanical method, the water consumption is reduced, but this method is still not suitable for areas where fresh water is scarce. Its desalination cycle is long, the desalination plant occupies a large amount of land, and the space utilization rate is low, which cannot meet the emergency requirements.

In addition, the control of the production line of this method is not standardized and mature, and the key parameters affecting the desalination quality, such as freshwater quality, water consumption, elutriation time, etc., are not yet standardized. Even the salt content of different batches of desalinated sand produced by the same production line is quite different.