Process for recovering soda from slags of the soda-desulphurisation of pig iron

摘要

Soda (Na2CO3) is obtained from soda slag of pig iron desulphurisation by leaching with the addition of CO2, in which specifically Na and S, but no Si compounds, go into solution. This forms H2S and NaHCO3. In addition, the leaching times are long. The new process has leaching times of less than half an hour and avoids the formation of H2S and NaHCO3. In the leaching (1), no CO2 is fed in. This makes Si compounds, in addition to Na and S, also go into solution. The Si constituents are precipitated (3) together with the S constituents. CO2 is then added (6) in only that amount which is required for the formation of the soda. The separation of the precipitation products is supported by at least one additive which agglomerates (4) the precipitation products and prevents an adsorption or coprecipitation of Na ions or Na compounds with the Si-containing precipitation products. Recovery of soda from soda slags.