scholarly journals Environmental Safety Analysis of Red Mud-Based Cemented Backfill on Groundwater

Author(s):  
Shuai Li ◽  
Yulin Zhang ◽  
Ru Feng ◽  
Haoxuan Yu ◽  
Jilong Pan ◽  
...  

As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement–sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50–100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.

2013 ◽  
Vol 773 ◽  
pp. 283-288
Author(s):  
Xing Zou ◽  
Xiang Quan Chen ◽  
Hai Chao Xie ◽  
Xiao Dan Qiu

The manganese sulfate solution leached from low-grade pyrolusite with pyrite and H2SO4 contains heavy metal ions of high concentration, influencing the quality of the final products of manganese compounds and causing manganese ions not to be electrolyzed. The present study was focused on the separation of Co, Ni and Zn ions from the leached solution with BaS. By controlling the pH value at 5.0-6.5, temperature at 50-60°C, reaction time at 15 min and mixing velocity at 78 rpm, the heavy metal ions could be separated effectively. Under the above optimized conditions, the ion concentration of Co, Ni, and Zn in the solution was reduced to 0.06 mg.L-1, 0.27mg.L-1 and 0.01mg.L-1, and the separation efficiency was 99.72%, 99.18% and 99.9% respectively. The obtained pure solution meets the demands of manganese electrowinning.


2011 ◽  
Vol 225-226 ◽  
pp. 1262-1265 ◽  
Author(s):  
Yan Fei Ma ◽  
Xue Dong Feng

Red mud as environmental restoration materials has the characteristics of low cost, simple process and controlling waste by waste. The paper introduced the application of red mud on heavy metal contaminated water and soil in details. Powdered or granular red mud both has good adsorption efficiency of Cu , Zn, Pb, Ni, Ca, Cd, As and other heavy metal ions in wastewater. Langmiur or Frendlich model can express the adsorption isotherm of red mud on heavy metal ions. Red mud can not only solidify the heavy metals in soils, but also increase the soil microbial activity and population types. At the same time, de-alkali treatment can not be ignored in the process of using red mud avoiding the second pollution to environment, and achieve the zero pollution release of red mud.


2014 ◽  
Vol 893 ◽  
pp. 457-460
Author(s):  
Xing Zou ◽  
Xiao Dan Qiu

Separation of trace heavy metal ions with BaS from solutions of five kinds of systems was studied. One was prepared with the solution (called as original solution here) leached from pyrolusite with pyrite and H2SO4, and the other four kinds of systems were prepared in the laboratory according to the composition of the original solution. They are respectively: a ternary system of NiSO4CoSO4ZnSO4; two quaternary systems of (NH4)2SO4NiSO4CoSO4ZnSO4 and MnSO4NiSO4CoSO4ZnSO4; a quintuple system of MnSO4(NH4)2SO4NiSO4CoSO4ZnSO4. The experiments have researched the effect of reaction time and dosage of BaS on the separation of heavy metal ions. According to the results, it took the five systems 10minutes to reach the equilibrium state and re-dissolution was found in the results. As the increasing of BaS dosage, the residual heavy metal ions would reduce, but the results of five systems were different when the same BaS was used.


2018 ◽  
Vol 358 ◽  
pp. 441-449 ◽  
Author(s):  
Wu-Ming Xie ◽  
Feng-Ping Zhou ◽  
Xiao-Lin Bi ◽  
Dong-Dong Chen ◽  
Jun Li ◽  
...  

2019 ◽  
Vol 207 ◽  
pp. 789-800 ◽  
Author(s):  
Xiao Chen ◽  
Yugang Guo ◽  
Song Ding ◽  
Haoyu Zhang ◽  
Feiyue Xia ◽  
...  

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