| Arsenic-containing waste water and tailings are two main origins of arsenic pollution and also two important starting points of both treating arsenic pollution and recovering arsenic resource. In this paper, the relative technologies about the treatment of arsenic pollution and the recovery of arsenic resources were analyzed and compared, and based on which two new types of cleaner technologies for both preventing arsenic pollution and recovering arsenic resources were studied and exploited.The piling-up of As-S tailings resulted in arsenic pollution and arsenic resource waste, while the existing technologies for refining, enriching, or utilizing it are with the disadvantages that it can result in serious pollution, or it is uneconomical for utilizing tailings, or the product is with a low purity which can not meet with the medicinal requirements, or it can not utilize the tailings with low main content, or the processing quantity is limited which make it.difficult to realize large-scale production. In this paper, a new process flow "floating -eliminating impurity by chemical method-preparing block by powder metallurgical method "for preparing blocky medicinal realgar (orpiment) from the tailings was put forward; Furthermore, the key process " eliminating impurity by chemical method and preparing block by powder metallurgical method " were studied by experiments in which the compact blocky medicinal realgar (orpiment) were got while it bring about little pollution. The new process flo%v hold obvious advantages that it is with higher resources-utilizing ratio, better product quality, lower production cost, and higher benefit on environment, so that by applying such process, the objective of eliminating the arsenic pollution and avoiding the arsenic resources waste resulted by As-S tailings piling -up were achieved.Most of the existing methods for eliminating arsenic from waste water focus on the purifying efficiency, not on the separation of arsenic from the other elements, which make the dregs can't be utilized, so that the methods tend to result in secondary pollution and resources waste. In this paper, based on the thermod>Tiamic analysis on As:S3-H:0 system, the feasibility of realizing selective arsenic removal by sulfurizaton-precipitation was theoreticallystudied; Furthermore, the process conditions for eliminating arsenic from a specific arsenic-containing solution "indium metallurgical solution" were studied through experiments. The results of both the theoretical analysis and the experiments indicate that the controlling of process conditions, especially the adjustment of acidity, is the key for realizing selective arsenic removal; that on better process conditions, the arsenic removal ratio can be up to 99.1%, and the purity of the arsenic -removal dreg is high with main content As;S3 mass fraction 95.4%, which make the dreg is liable to be utilized. Consequent!}', the objectives of avoiding the generation of virulent pollutant AsH3, eliminating the secondary arsenic pollution resulted by the dreg piling-up, and recovering arsenic resources were achieved. The technology is instructive to the arsenic removal of other industrial wastewater.The main parts of the cleaner production process flow for preventing arsenic pollution and recovering arsenic resources are as follows: the selective sulfurization-precipitation of arsenic-containing waste water (solution), the comprehensive utilization of arsenic-containing tailings (arsenic removal dregs), the enrichment of As-S tailings by floatation, the purifying of the powder obtained by floatation, preparing blocky medicinal realgar (orpiment) from the purified powder by powder metallurgical methods. By applying such process flow, the objective of both preventing arsenic pollution and recovering arsenic resources can be realized. Moreover, the cleaner production can be realized. |
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