Abstract: Process of refining of a metal bath in a crucible with oxygen blast at the top and crucible used.The invention consists essentially of providing in the bottom (15) of the crucible agitating gas injectors (15) located at least in a peripheral circular ring situated in immediate proximity to the refractory side wall. The injectors are preferably concentrated opposite the journals. Secondary injectors are, also preferably, provided in the bottom zone, intermediate between the ring and the center of the crucible.The invention makes it possible, in relation to the prior injection practice, to reduce the rate of dissolution of the agitating gas in the molten metal and then makes it possible to use a low-cost agitating gas, such as nitrogen, without risk of excessive nitridation of the bath.

Abstract: A process for refining a metal bath in a converter by oxygen blowing, particularly a molten metal liquid bath containing cold, solid substances, notably of scrap. Oxygen is distributed over the surface of the bath, so that there will be an after-combustion of CO released in the course of decarbonization. The thickness and consistency of a slag layer formed over the bath is actively regulated by injecting a rising inert gas through the bottom of the bath. The flow of rising gas may be regulated depending upon the oxygen content in the fumes of the converter, or upon the intensity of emission through the top of an oxygen blowing lance.

Abstract: A ferrous melt, e.g. of steel, is refined beneath a slag layer by blowing from above with an oxygen-containing gas through a lance and by bubbling an inert gas through the melt from the bottom. According to the invention, the consistency of the slag layer and/or its level is continuously detected on the one hand and the rate of decarburation of the bath is detected on the other hand and in response to these measurements the volume rate of flow of the bubbling gas is controlled on the one hand to maintain a predetermined spacing of the slag layer from the head of the lance and, on the other hand, a fluid consistency of the slag.

Abstract: A process for refining a steel melt in a furnace in which a steel melt is formed with a slag layer thereon, the thickness of which can be controlled by passing a stream of inert gas upwardly through the melt, while directing a first stream of oxygen into the melt from a lance positioned above the melt for the top-blowing refining thereof to produce carbon monoxide above the melt and feeding a second stream of oxygen from the lance for the post-combustion of the released carbon monoxide, while monitoring continuously the thickness of the slag layer, the height of the melt, the carbon monoxide post-combustion factor (%CO.sub.2 /%CO+%CO.sub.2) and the speed of decarburization of the melt and controlling the height of the lance above the melt and the discharge rates of total blown oxygen, the second stream of oxygen and the inert gas stream at any given time in accordance with a particular relationship.

Abstract: Slag is conditioned during blowing from above with oxygen of an iron melt by bubbling an inert gas into the melt from the bottom of the crucible in response to measurements made of the flowability of the slag layer and the speed of decarburization.

Abstract: Coal of a granulometry of 0.1 to 20 mm is injected into the blast-pipe manifold surrounding an iron-smelting blast furnace. The temperature of between 900.degree.C and 1300.degree.C in this manifold thermally disintegrates the coal by vaporizing volatile components such as water in the coal and reduces the coal to a mesh size of at most 1 mm. The fine particles of coal so produced are blown into the blast furnace through the tuyeres.