Composite catalyst, method for producing composite catalyst, method for producing lower olefin and method for regenerating composite catalyst

A composite catalyst for producing a lower olefin from a hydrocarbon feedstock, comprising:

• a zeolite being a crystalline aluminosilicate containing gallium and iron or iron in the framework of the zeolite and further having a framework with 8- to 12-membered ring;
• and
• silicon dioxide,
• wherein
• when the zeolite is a crystalline aluminosilicate containing iron and gallium, and
• an acid density as a composition ratio of the number of moles of silicon to a sum of the number of moles of iron, gallium, and aluminum is 75.0 to 200.0, a composition ratio of the number of moles of gallium to a sum of the number of moles of iron, gallium, and aluminum is 0.1 to 0.4, and a composition ratio of the number of moles of iron to a sum of the number of moles of iron, gallium, and aluminum is 0.2 to 0.6,
• and
• when the zeolite is a crystalline aluminosilicate containing iron, and
• an acid density as a composition ratio of the number of moles of silicon to a sum of the number of moles of iron and aluminum is 75.0 to 200.0, and a composition ratio of the number of moles of iron to a sum of the number of moles of iron and aluminum is 0.4 to 0.7.