Large crystal, organic-free chabazite, methods of making and using the same

A method of selective catalytic reduction (SCR) of NOx in exhaust gas, said method comprising:

• contacting exhaust gas with an article comprising a metal-containing CHA type zeolite synthesized without the use of an organic structural directing agent, said zeolite having a crystal size greater than 0.5 microns and a silica-to-alumina ratio (SAR) between 5 and 15.

A method of making a microporous crystalline material comprising a aluminosilicate zeolite having a CHA structure, a silica-to-alumina ratio (SAR) ranging from 5 to 15, and a crystal size greater than 0.5 microns;

• said method comprising mixing sources of potassium, alumina, silica, water and optionally a chabazite seed material to form a gel, wherein said gel has potassium to silica (K/SiO2) molar ratio of less than 0.5 and hydroxide to silica (OH/SiO2) molar ratio less than 0.35;
• heating said gel in a vessel at a temperature ranging from 80° C. to 200° C. to form a crystalline large crystal chabazite product;
• ammonium-exchanging said product.