While asbestos use in the United States has declined quite steadily over the years, one industry in particular still relies on the mineral for its processes. Throughout the past few years, the chlor-alkali industry has used most or all of the asbestos imported into the U.S. In 2016, the EPA noted that 340 metric tons ofchrysotile asbestos被进口，所有这些都是由氯烷烃植物食用的。
尽管在美国使用石棉的使用下降，但在许多其他国家，市场仍在增长。尤其是氯 - 阿尔卡利行业仍在使用石棉在全球范围内, with many plants in China also using toxic mercury processes. Though more and more plants, especially throughout Europe, have slowly adopted safer manufacturing methods, many still rely on these older asbestos or mercury involved methods that have been used for well over 100 years.
除了留下更大的碳足迹和损害环境外，这些较旧的方法还使工人处于风险万博专业版和其他严重的健康问题。
What is the Chlor-Alkali Industry?
In essence, this industry is vital to the larger化学工业，以及我们日常生活的其他各个方面。氯烷烃产业生产三个必不可少的产品：氯，氢氧化钠（也称为苛性钠）和氢。
氯是制造最重要的产品，因为它在许多化学过程和工业环境中都使用。例如，氯用于从医疗设备（93％的美国药品）的无数产品中使用，绝缘，当然，还有助于消毒游泳池。在大多数情况下，研究人员发现没有可行的氯替代品。除了提供更好的健康和安全性外，氯是资源保护和利用太阳能的重要因素。
In the manufacturing of chlorine, the co-products of caustic soda and hydrogen are also vital for many other industries. Caustic soda, an alkali, is used often in the food industry, textile production and creating soaps and other cleaning agents. Hydrogen has many uses as well, most notably for the creation of hydrogen peroxide and ammonia.
总体而言，氯行业是世界各地的大型生产国，因为这些产品对于我们日常生活的许多方面至关重要。在全球范围内，2016年生产了6500万吨氯，在美国生产了1400万吨，在欧洲生产了1000万吨氯。仅在美国，氯 - 阿尔卡利行业每年至少产生80亿美元的销售，并直接雇用约20,000名工人，并在相关行业中创造了数千个其他工作。
Though chlorine manufacturing is vital for many applications and is largely considered to be a positive economic factor, some of the procedures in place for producing these materials are putting theworkers at risk of asbestos exposure.
石棉用于氯制造
Manufacturing chlorine has been in practice for well over a century, though many plants still use more toxic and unsafe methods to produce it. In general, the industry relies on three basic manufacturing processes:
- The mercury cell process
- 隔膜细胞过程
- The membrane cell process
所有这些过程都取决于相同的基本化学。氯及其副产品是通过将盐溶液与直接电流电溶液产生的，该盐溶液最终将氯离子转化为氯。虽然汞细胞过程在全球范围内正在减少，并且欧洲大部分地区都采用了膜细胞过程的更安全选择，但美国的几家植物仍使用石棉制成的膜片。
隔膜细胞过程可与水和氯化钠的组合起作用，从而产生盐水，该盐溶液经过加工和过滤以去除杂质。将热量施加到溶液中，并添加更多的盐，直到为电流制备纯化的盐水溶液，这是asbestos materialscome into play.
石棉膜片通常用于分离阴极和阳极，这将产生电流。尽管美国地质调查局在最近的石棉研究中指出，越来越多的植物正在寻找石棉隔膜的替代品，但今天至少有15种植物仍在使用这些产品。根据EPA的说法，典型的植物将使用5 – 25 tons of asbestos each year在这些隔膜的生产中。
The industry relied on making asbestos diaphragms because of the mineral’s durability and chemical resistance. These properties help the diaphragm prevent the caustic soda also being produced in the process from reacting with the chlorine.
The mercury process is just as dangerous, as workers apply liquid mercury for the cathode. Mercury exposure can cause a variety of health problems, some of which can be fatal. This manufacturing can also release mercury into the air, which can eventually accumulate in ecosystems and affect wildlife and the general population.
The membrane cell process is the newest method to produce chlorine and its products, and is regarded as the safest for both workers and the environment. This process relies on a membrane made of polymers that only allows positive ions to flow through, which means the remaining sodium chloride cannot contaminate the chlorine being produced. Polymers have no toxins that pose a risk for workers, and this method uses the least amount of energy and steam.
A Need for Change
尽管该行业中的许多人已经使生产变化为更安全的膜工艺，甚至是石棉隔膜本身的替代方案，但仍然有许多植物阻止。由于需要将这些植物转换为更安全的方法所需的时间和投资，因此他们可能抵制变化。
专家指出，根据设施，转换工厂可能需要1。5至2。5年。估计的投资约为开设全新工厂的成本的40％至50％，专家说，每公吨生产的氯的价格可能从500美元到700美元不等。
As long as the industry resists change, workers in these dangerous settings need to understand their rights and take action to protect themselves. Hopefully, the industry will change on its own sooner rather than later, and not simply wait fora ban on asbestosto force better safety at work.
