When the Tariff taxes are collected the Tariff Taxes money goes into the Federal Governments bank account.
Then the government uses the Tariff Taxes to fund the government and for the purpose to pay the interest on its debt), and also to act as a protective barrier around newly starting domestic industries.
Tariffs are good and bad and I personally think we should stop using and collecting Tariffs but some people are for it and that's okay as well.
The main reason that Tariffs were put in place for China to pay to the USA is because China was basically stealing ideas and claiming that they invented the product that they were making.
When in fact the design or invention of the items was made by someone or people in the USA.
For example China has made Knock Offs of shoes, clothing, small engines etc.