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A new scheme of the environmental classification standards for the bronze cultural relic’s preservation in museums

Li Dandan, Zhou Hao, Xu Fangyuan, Yan Ying, Wu Laiming, Cai Lankun

Environment Protection Engineering

2023

Vol. 49, nr 4

45--59

The environmental risk classification of the metal relics is usually determined by the corrosion rate of the metal but it is difficult to monitor the deterioration of the metal relics directly. A strong relationship exists between indoor exposure, the air quality classification of atmospheric corrosion, and the actual deterioration of metal relics. The copper-silver hanging plate method requires a long period of environmental exposure and has certain hysteresis, thus reflecting the current environmental quality of the museum in real time poses some difficulties. However, the application of the environmental reactivity monitor (ERMs) based on the piezoelectric effect can solve the above problems. The invented quartz crystal microbalance (QCM) reactivity monitoring device is applied to study the influence of temperature and humidity on the corrosion of the bronze-simulated materials and the relationship between the corrosion depth rate of the bronze-simulated materials and the frequency change of the crystal oscillator. Then, the recommended classification range of temperature and humidity and the airquality classification standards for the preservation environment of the bronze cultural relics in museums are proposed.

The effect of sodium carboxymethyl cellulose on the entrainment of zoisite in flotation

Zhang Zhengjun, Ou Leming, Jin Saizhen, Zhou Hao

Physicochemical Problems of Mineral Processing

2021

Vol. 57, iss. 2

34--47

During flotation, fine gangue minerals can enter the concentrate through mechanical entrainment, which seriously affects the quality of concentrate. In this work, the effect of sodium carboxymethyl cellulose (CMC) on the flotation performance of zoisite, a silicate mineral, was studied. The role of CMC in reducing zoisite entrainment was investigated by dynamic foaming tests, surface tension measurements, rheology measurements, sedimentation tests, and optical microscopy experiments. The flotation results showed that zoisite mainly entered the concentrate by entrainment; the addition of low dosages of CMC decreased zoisite entrainment and efficiently separated cassiterite from zoisite; moreover, the concentrate grade and recovery of SnO2 increased by 1.27 % and 5.63 %, respectively, by using CMC in closed-circuit flotation tests. Dynamic foaming studies on the two-phase and three-phase foam/froth revealed that the presence of CMC decreased the froth ability and froth stability, and greatly altered the three-phase froth structure. Basically, the bubbles in the foam were larger after adding CMC. For the two-phase foam, the change of foam property had little to do with surface activity and bulk viscosity. For the three-phase froth, the froth property was strongly affected by the interaction of CMC and zoisite. The results of the sedimentation test and microscopy experiment demonstrated that CMC can cause zoisite to flocculate and enlarge the particle size, which was the main reason for the decrease of froth stability and entrainment. This study indicates that the side effects of depressants should not be overlooked when discussing the role of depressants in flotation.