Method for removing sulphate from outdoor crisp brick cultural relic

Abstract

The invention discloses a method for removing sulphate from an outdoor crisp brick cultural relic. The method is as follows: spraying a salt-damaged crisp part of a brick body with a solution A evenly, then evenly spraying the salt-damaged crisp part of the brick body with a deionized water and solution B mixed liquid with the volume ratio of deionized water to solution B of 1: 6 to 9, and repeating spraying with the solution A and the deionized water and solution B mixed liquid for 3 to 8 times, wherein the solution A is an ethanol solution containing 5 to 15 g / L of phosphoric acid and 10 to25 g / L of dihydrate oxalic acid, and the solution B is a methanol containing 8 to 25 g / L of barium hydroxide octahydrate. According to the method, the outdoor crisp brick cultural relic is desalted for transformation of most destructive Na2SO4 in the brick relic into BaSO4 to deposit in the brick, chlorine salt and sulfate that are not involved in the transformation can be separated from the brickbody in the manner of moving of salts along with water; while desalination, reinforcement function is achieved, the ''fragile'' status of salt-damaged crisp powder of the brick body may not be aggravated, the mechanical strength is significantly increased, the salt penetration increases after the desalination, and the salt retention time in the brick can be reduced.

Description

technical field [0001] The invention belongs to the technical field of cultural relics protection, and in particular relates to a method for removing sulfate from outdoor crisp powder brick cultural relics. Background technique [0002] China's ancient buildings are mainly brick and wood structures, and the bottom of the building is mostly based on bricks. At present, there are many ancient brick cultural relics in China, such as the Great Wall, Xi'an City Wall, Nanjing City Wall, Xi'an Bell and Drum Tower, and Big Wild Goose Pagoda. During the preservation process, these bricks have suffered from physical, chemical and biological natural weathering for a long time, coupled with air pollution since industrialization, acid rain erosion, and varying degrees of man-made damage. In particular, the soluble salt inside the ground rises and migrates to the surface of the brick body as the water evaporates, and its repeated dissolution and crystallization cause a serious problem of...

AI Technical Summary

Problems solved by technology

Salt damage in outdoor brick cultural relics causes severe crispy powder parts to have low mechanical strength and fall off immediately. Using the above physical methods to directly remove soluble salt on the surface of cultural relics will not work well, which will aggravate the "fragile" status of cultural relics and destroy the original appearance , there is a potential safety hazard of brick peeling off, which does not conform to the principle of "minimum intervention" for cultural relics

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