High-performance heat-insulating materials

A heat-insulating material, formed from silica particles of submicron porosity,

• wherein the heat-insulating material is a solid silica foam incorporating two different ranges of porosities, including:
• a first range of macropores with diameters of between 10 microns and 3 mm;
• and
• a second range of submicron pores with diameters greater than 4 nm and less than 300 nm,
• wherein the pore volume for the submicron pores ranges from 1 to 1.5 cm3/g, and the pore volume for the macropores is from 3 to 15 cm3/g,
• wherein the heat-insulating material has a mass per unit volume of the heat-insulating material is less than 300 kg/m3, and
• wherein the silica particles of submicron porosity do not comprise aerogels, the silica particles of submicron porosity have submicron pores with diameters of greater than 4 nm, and the silica particles of submicron porosity have a specific surface area less than or equal to 500 m2/g.