robertjohnson.work/assets/plugins/font-awesome/scss/_animated.scss

// Animated Icons
// --------------------------

.#{$fa-css-prefix}-spin {
  animation: fa-spin 2s infinite linear;
}

.#{$fa-css-prefix}-pulse {
  animation: fa-spin 1s infinite steps(8);
}

@keyframes fa-spin {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
}