Laboratory Evaluation And Research On Desalination Effect Of Sandstone Stone Cultural Relics Materials

In order to know that effect of the current desalination material and method of lithoid cultural relic,the mechanism and expression of the salt damage of lithoid cultural relics are sorted through the research literature and case study on the desalination of common lithoid cultural relics at home and abroad,and the common desalt materials and application status at home and abroad are collected,This paper summarizes the methods of desalting(especially application method),application range and effect evaluation of common lithoid cultural relics.On this basis,by purchasing 7 kinds of stone cultural relics desalting materials in the current market,including commonly used deionized water,rice paper pulp,Sprite ? commercial salt-discharging mortar,Sprite ? wall salt-discharging pulp(DP-02),foreign more common kaolin and bentonite-based dressing agent),Desalting Compression(application material),etc.,selected 8 sets of sandstone-like blocks with consistent physical and chemical properties(1 of which were blank),desalinated the 7 kinds of desalted materials in the laboratory,and evaluated its desalting effect.The experimental research and preliminary conclusions of the thesis are as follows:(1)Study on physical properties of sandstone-like blocks.The appearance and microstructure of sandstone-like blocks were analyzed by three-dimensional video microscope and scanning electron microscope,the mineral composition of sandstone-like blocks was analyzed by X-ray diffraction,the permeability and water absorption of sandstone-like blocks were analyzed,indirect detection of sample block strength by low-frequency ultrasonic waves,analyzing the concentration of soluble salt in sandstone-like blocks in the vertical direction by using a conductivity meter and an ion chromatograph;and analyzing the research of sandstone porosity and pore radius by using a mercury-mercury instrument.The results show that the selected sandstone-like block mineral is mainly quartz and feldspar,the deposition is uniform,the water absorption is good,a small amount of soluble salt is found in the vertical direction,and the concentration difference is small,the pores are capillary pores,and it is suitable to characterize the desalination effect before and after desalination.(2)The laboratory simulated the damage of soluble salt to sandstone.This part simulates the destruction of sandstone by capillary action in laboratory simulated single salt and mixed salt.The results show that the sodium sulfate salt has obvious damage to the sandstone and which is relatively short in time.At the same time,the surface of the sandstone-like block is crystallized into a loose white powder,so that the surface of the sandstone-like block is weathered,and the part of the sandstone-like block is completely weathered,and the salt is crystallized into white particles on the surface of the sandstone-like block,the crystalline layer is relatively tight and firm;the mixed salt is crystallized into white spherical particles on the surface of the sandstone-like block,and the crystalline layer is very hard.(3)Comparison study of desalting effect of laboratory sandstone-like blocks,including soaking in deionized water and pasting and desalting.The screened salt-discharging paper pulp,the salt-discharging mortar,the clay mineral coating agent,the kaolin/ cellulose/ quartz sand,the bentonite/ cellulose/ quartz sand and the commercial salt-discharging mortar.Desalting Complex are applied to the desalting material,and the desalting experiment is carried out,meanwhile,compared with the deionized water soaking method;The desalting effect is evaluated by analyzing anion concentration,the quality,ultrasonic wave velocity and porosity of sandstone-like block before and after desalination.The results show that the effect of deionised water soaking is good for desalination,but it is only suitable for small pieces,preserved in good condition,firm in texture and without color painting,so the scope of use is limited.In the application desalting material,the material with better effect is salt-discharge paper pulp,salt-discharging mortar and bentonite.(4)Desalination field experiment of sandstone cultural relics.The mineral composition,soluble salt type and concentration and porosity of sandstone are studied and analyzed on the surface of sandstone cultural relics.According to the preliminary desalting effect evaluation experiment analysis,we selected the salt-discharging pulp sticking as desalting material to carry out salt removal.The salt-soluble paper pulp of the salt-removing capacity is obvious.In this paper,the laboratory desalting research is carried out on the commonly used plaster desalt materials at home and abroad,and the parameters and indexes which can be compared with the desalination effect are preliminarily selected,so as to help the stone relic protection practitioners to know the desalination effect of the selectable desalting material on the market at present,At the same time,the method of desalting method and effect of applying material introduced in this paper also provides a new idea and reference for the desalination research of lithoid cultural relics in China.