by weight depending on the type of sodium silicate sodium silicate is a generic term for a family of chemicals composed of sodium oxide na 2 o silica sio 2 and usually water h 2 o the proportion of na 2 o to sio 2 in sodium silicates is expressed as a weight ratio with the alkali component held at unity commercial grades of liquid sodium silicate are usually concentrated for convenient handling for instance sodium silicate having a weight ratio of 3 22 can readily be handled up to a solids content of about 39 8 percent which is equivalent to approximately 43 u00b0 baume a liquid sodium silicate solution as employed in the invention has a weight ratio of 3 22 a solids content of 37 6 percent a density of 41 0 u00b0 baume and a viscosity of 180 centipoises liquid sodium silicate as used throughout this specification refers to this 37 6 percent solids sodium silicate solution unless otherwise specified other sodium silicates can be utilized but it is preferable to maintain the na 2 o at the lowest possible ratio to sio 2 thus the 3 22 mixture which is also the most readily available commercially is the preferred ratio the sodium silicate solution brings to the binder composition the property of rendering the subsequent agglomerates or briquets rust resistant pitch having a ring and ball softening point in the range from about 90 u00b0 c to about 210 u00b0 c but preferably in the range from about 120 u00b0 c.