Abstract:Pierce-Smith copper converting process is widely used as a matured technology, but there are many problems inherent, for example, discontinuous operating, SO 2 gas let out and so on. So environment protection is difficult. However, copper flash converting process is continuously and the waste gas quantity is both small and steady. The price of construction and operation is low. The environment will be protected. The advantage of Flash converting process compared with Pierce-Smith copper converting process used by a new built or old rebuilt copper smelter has discussed in detail.