Process for producing a ceramic product for use as a construction material

A process for producing a road paving brick, which comprises

• (a) adding from 5 to 35% by weight, based on the total weight, of sludge ashes to earth suitable for the production of bricks wherein sufficient amounts of CaO, MgO, and P.sub.2 O.sub.5 have been added to said sludge ashes whereby said sludge ashes contain from 0.3 to 0.8 mole of CaO in Seger formula, from 0.1 to 0.5 mole of MgO in Seger formula, and 0.2 mole or more of P.sub.2 O.sub.5 in Seger formula,
• (b) mixing the whole to prepare a body,
• (c) supplying the body into a die and pressing the body into a desired shape in a wet process, and
• (d) firing the molded body at a temperature of from 900.degree. to 1,200.degree. C.

A process for producing a roofing tile, which comprises

• (a) adding from 15 to 35% by weight, based on the total weight, of sludge ashes to earth suitable for the production of a roofing brick wherein sufficient amounts of CaO, MgO, and P.sub.2 O.sub.5 have been added to said sludge ashes whereby said sludge ashes contain from 0.3 to 0.8 mole of CaO in Seger formula, from 0.1 to 0.5 mole of MgO in Seger formula, and 0.2 mole or more of P.sub.2 O.sub.5 in Seger formula,
• (b) mixing the whole to prepare a body,
• (c) supplying the body into a die and pressing the body into a desired shape in a wet process, and
• (d) firing the molded body at a temperature of from 900.degree. to 1,200.degree. C.

A process for producing a wall tile, which comprises

• (a) adding from 2 to 40% by weight, based on the total weight, of sludge ashes to earth suitable for the production of a wall tile, wherein sufficient amounts of CaO, MgO, and P.sub.2 O.sub.5 have been added to said sludge ashes whereby said sludge ashes contain from 0.3 to 0.8 mole of CaO in Seger formula, from 0.1 to 0.5 mole of MgO in Seger formula, and 0.2 mole or more of P.sub.2 O.sub.5 in Seger formula,
• (b) mixing the whole to prepare a body,
• (c) supplying the body into a die and pressing the body into a desired shape in a dry process, and
• (d) firing the molded body at a temperature of from 900.degree. to 1,200.degree. C.

A process for producing a porcelain tile, which comprises

• (a) adding from 10 to 40% by weight, based on the total weight, of sludge ashes to earth suitable for the production of a porcelain tile, wherein sufficient amounts of CaO, MgO, and P.sub.2 O.sub.5 have been added to said sludge ashes whereby said sludge ashes contain from 0.3 to 0.8 mole of CaO in Seger formula, from 0.1 to 0.5 mole of MgO in Seger formula, and 0.2 mole or more of P.sub.2 O.sub.5 in Seger formula,
• (b) mixing the whole to prepare a body,
• (c) supplying the body into a die and pressing the body into a desired shape in a dry process, and
• (d) firing the molded body at a temperature of from 900.degree. to 1,200.degree. C.