Low NO.sub.x formation burner apparatus and methods

An improved burner apparatus for discharging a mixture of fuel gas and air into a furnace wherein said mixture is burned and flue gases having low NO.sub.x content are formed therefrom comprising:

• a refractory burner tile attached to said furnace having a base portion and a wall portion, the wall portion extending into said furnace, surrounding a central area of said base portion and having exterior sides which slant towards the central area of said base portion;
• means connected to said burner tile for mixing a portion of said fuel gas with said air and discharging the resulting primary fuel gas-air mixture into a primary burning zone in said furnace from within the space defined by the central area of said base portion and the interior of said wall portion of said burner tile;
• and
• at least one secondary fuel gas nozzle means positioned outside said wall portion of said refractory burner tile adjacent the intersection of an external slanted side of said wall portion with the surface of said base portion for discharging the remaining portion of said fuel gas adjacent to an external slanted side of said wall portion and spreading said fuel gas over said slanted side whereby said fuel gas mixes with flue gases in said furnace and burns in a secondary burning zone therein.