function get_primary_category_icon($post_id){
	global $wpdb;
	$query = "SELECT * FROM `".$wpdb->prefix."postmeta` WHERE `post_id` = ".$post_id." AND `meta_key` = '_yoast_wpseo_primary_category'";
	$res = $wpdb->get_results($query);
	$cat_id = $res[0]->meta_value;

	return $cat_id;
}