Preparation method for durable cement anti-permeability powder and production system for durable cement anti-permeability powder

The invention provides a preparation method for durable cement anti-permeability powder and a production system for the durable cement anti-permeability powder. Hydrophobic nanosilicon dioxide accounting for 2% to 5% of the total mass of Portland cement is added in the cement hydration process, and silicate gel micro-crystals are generated through hydrophobic nanosilicon dioxide and used for filling of finished cement gaps. The production system for the durable cement anti-permeability powder comprises a stirring assembly and an adding assembly. The adding assembly comprises an additive containing box and a conveying pipe. An electronic valve is arranged on the conveying pipe, and the additive containing box is communicated with the connecting pipe through a conveying pipe. By means of the scheme, before cement is used or during construction, hydrophobic nanosilicon dioxide accounting for 2% to 5% of the total mass of the cement is added, during the hydration process of the Portland cement, hydrophobic nanosi