In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace, the conventional way to deal with it is that the CaCl2 solution is prepared by tap water, and then the solution is sprayed onto the sintered ore for improving its RDI (low temperature reduction degradation index). The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI. The values of RDI+6. 3 and RDI+3. 15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3. 5% (mass percent) are increased by 17. 5% and 11. 63%, but the index of RDI-0. 5 is decreased by 3. 1% when the spraying amount of the solution is making up 0. 5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution. Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore, RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available, by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.

In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace, the conventional way to deal with it is that the CaCl2 solution is prepared by tap water, and then the solution is sprayed onto the sintered ore for improving its RDI (low temperature reduction degradation index). The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI. The values of RDI+6. 3 and RDI+3. 15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3. 5% (mass percent) are increased by 17. 5% and 11. 63%, but the index of RDI-0. 5 is decreased by 3. 1% when the spraying amount of the solution is making up 0. 5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution. Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore, RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available, by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.