氨水中微量金屬去除技術探討

Abstract

液氨為高壓氣體勞工安全規則所稱之特定高壓氣體、可燃性氣體及毒性氣體。氨氣對呼吸系統會產生強烈刺激性且具有窒息性，氨普遍應用在工業製程上，如遇有儲存異常、操作異常或管線腐蝕造成洩漏，或發生運輸事故造成洩漏，將對人體產生立即性危害及對環境造成衝擊。 過去液氨主要係用於農業肥料製造之原料、一般工業應用及冷凍業冷媒之用，以當時液氨產品之純度已足夠提供各業之使用；但近年來科技產品突飛猛進不斷創新發明，例如：積體電路、太陽能產業及LED產業之興起，其製程需使用氨水洗淨，將微量污染物徹底清除。然以目前進口之液氨所調配出的氨水，因含有多種微量金屬，會污染產品，其純度已無法應用於諸等高科技產業製程上，因此亟需研產高純度之氨水。 本研究採實驗方式，將工業級液氨加熱使氣化成氣氨或直接自液氨儲槽頂部將已蒸發之氣氨直接導入第一氨氣淨化槽，氨氣經分配管細微孔徑流出後產生細微氣泡並與飽和之氨水充分接觸，微量金屬被留存於飽和氨水中，淨化後之氨氣則進入第二氨氣淨化槽，將殘存之微量金屬再度去除，如此共三道淨化系統，徹底將氨水中三十餘種微量金屬去除將盡。實驗結果已達到並優於業界需求之品質，冀望本研究成果能提供國內業界高品質、低價格之產品，使本土產業更具競爭力，使國內經濟更加繁榮。

Anhydrous ammonia is specific high pressure gas, combustible gas and toxic gas, which referred from Rule on Labour Safety in High Pressure gas. For human respiratory system, ammonia is regarded as strong irritant and asphyxiating gas. Both anhydrous ammonia and ammonia has widely applied in industrial process. Thus, inappropriate storage, incorrect operation or leakage caused by pipeline corrosion or transportation accidents, these situations would lead to immediate damage for human and environmental impact. In the past, anhydrous ammonia has been used on agricultural raw material of fertilizers, industrial application and refrigerant. However, the areas of integrated circuits (IC), solar energy and light emitting diode (LED) industries base on rapidly advancing on technologic products invention and innovation in recent years, these production processes utilize ammonium hydroxide as completely clearing liquid for trace pollution. Currently, ammonium hydroxide which made from imported anhydrous ammonia contains several trace metals. Therefore, this kind of ammonium hydroxide not only contaminates the products but cannot be employed by various high–tech industries as well. Consequently, it is necessary that research and production on high purity ammonium hydroxide. The experiment of this study use ammonia gas from gasification of industrial grade anhydrous ammonia or directly use ammonia gas from top of anhydrous ammonia tank. Next, let this ammonia gas transfer into first ammonia refinement tank. The ammonia gas effuses through meticulous hole which on distributed tubes and small ammonia gas bubbles come out. The bubbles contact with saturated ammonium hydroxide and then the trace metals are retained in saturated ammonium hydroxide. After this process, ammonium hydroxide be purified and be transferred into the second ammonia refinement tank. Following the process would be repeated as same as the gas transfer into first ammonia refinement tank; therefore, the remainder trace metals would be eliminated. Consequently, these three cleaning system enable completely remove over 30 kinds of trace metals from ammonium hydroxide. The result of this experiment exceeds the quality request of industries. The object of this research is that providing high quality and economical ammonium hydroxide for domestic enterprises. It will boost local industries’ competitiveness and prosper domestic economy.