How should high levels of arsenic in pyrite be dealt with?

It would be best to specify what the arsenic content is Only others know the extent of the arsenic excess, so they can answer your question.

To improve purification, arsenic removal equipment should be added, and arsenic removers such as ferrous sulfate should be incorporated into the wastewater discharged

The arsenic pollution incident in Yangzonghai Lake, Yunnan, is actually just the tip of the iceberg regarding the arsenic pollution problem in China’s sulfuric acid industry; the severity of this issue has only just come to light. At present, most sulfuric acid produced in China is derived from mineral sources, and minerals in most areas of southern China contain arsenic. In the industry, minerals with an arsenic content of no more than 0.5% are considered acceptable for sale and use in the production of sulfuric acid. Far above **the standard. Some companies pursue profits unilaterally, even using high-arsenic ore with an arsenic content of around 2% to produce sulfuric acid. This is already a well-known secret in the industry. The arsenic referred to in arsenic pollution is actually arsenic trioxide, which is what people commonly call arsenic. To solve this problem, the focus should be on the source; one cannot wait until pollution occurs before finding a solution. Companies also cannot be simply shut down carelessly. Currently, the following methods are used in the industry to solve this problem ； 1. The use of high-arsenic ore is prohibited; sulfuric acid manufacturers must use ore that meets **standards** for production. Mining enterprises must improve ore processing to produce minerals that meet **standards**, and separate out ores with high arsenic content. II. The separately selected high-arsenic ores should be treated collectively, as ordinary ore-based acid production methods do not possess the capability for such treatment. 1. The traditional method involves acidification roasting in the early stage of acid production, during which arsenic is converted into arsenic pentoxide, which then combines with slag to form ferric arsenate – what is commonly referred to as solid-arsenic roasting. There are issues of secondary pollution and resource waste involved here. 2. Over the past decade, the Research Institute of Nanhua Group has developed three new technologies for arsenic treatment: first, arsenic is burned into flue gas to produce qualified roasted slag; then, arsenic trioxide with a purity of over 95% is obtained; and finally, qualified sulfuric acid is produced. They have all been successfully applied in practice, and relevant patents have been filed. The details are as follows. A. Two stages of calcination, spray cooling, and collection in a bag filter ； B. One stage of roasting, dry gas cooling, collection using gravity bag filters ； C. Hot concentrated acid washing, cooling and crystallization, followed by drying and collection. The above three processes cover various methods for producing acid from minerals; not only is sulfuric acid production from pyrite possible, but they can also address similar issues in the production of acid from smelting flue gases

Just add ferrous sulfite to the mine

It can be removed during the purification process, but it requires some effort when treating the water. But it’s easy to handle. Treated by the lime-iron salt method, the arsenic content after treatment is less than 0.10 mg/l.

Thank you all for your suggestions~~~~ If ferrous sulfite is added to the mine, to what level can arsenic be controlled? Is there also a formula for the appropriate ratio of ferrous sulfite to be used?