Abstract: The preparation of unburned brick with solid waste is an important way to realize mass utilization of the solid waste.In order to determine the possibility of electrolytic manganese slag from a electrolytic manganese plant in Guizhou to prepare the unburned brick,and based on the leaching toxicity analysis,the effect of sludge-cement mass ratio,aggregate dosage,liquid-solid ratio,molding pressure on the flexural and compressive strength of brick were studied.The results showed that with the increase of sludge mass ratio,the compressive and flexural strength of the test block were firstly increased and then decreased,and reached the highest when the sludge-cement mass ratio was 5;With the increase of aggregate dosage,the compressive and flexural strength of the test block were increased firstly and then decreased with the highest value at the aggregate dosage of 30%;With liquid-solid mass ratio increasing,the compressive and flexural strength of the test block were increased firstly and then decreased with highest value at water-solid ratio of 0.30;The molding pressure was increased from 1 MPa to 2 MPa,and the compressive strength and flexural strength of the test block for 7 d and 28 d were increased significantly,and its rate of increase was slowed when the molding pressure was gradually improved.Under conditions of the sludge-cement mass ratio 5,the aggregate dosage of 30%,the liquid-solid ratio 0.3,the molding pressure at 2 MPa,the unburned brick with electrolytic manganese slag owns compressive strength and flexural strength 10.63 MPa and 2.21 MPa for 7d respectively,14.89 MPa and 2.48 MPa for 28 d respectively,which reach the national strength standard for common brick.

Key words: Electrolytic manganese residue, Compressive strength, Flexural strength