Evolution of the flame at the outlet of a Manhès-David converter during the blowing. We can notice the following steps : * dark reddish-brown flame and heavy white fumes (oxydising of the secondary components) * apple-green flamme (oxydising of the iron sulphide) * white blueish flame (oxydising of the copper, with may slag in the converter) * thin red-puple flame (oxydising of the remaing sulphur)