In 1723, the Kangxi Emperor's successor, the Yongzheng Emperor, sent an army of 230,000 led by Nian Gengyao to quell a Dzungar uprising in Qinghai on the Qinghai-Tibet plateau. Due to geography, the Qing army  was at first unable to engage their more mobile enemy. Eventually, they met the Dzungars and defeated them. This campaign cost the treasury at least eight million silver taels. Later in Yongzheng's reign, he sent a small army of 10,000 to fight the Dzungars again. However, that army was annihilated near the Khoton Lake in 1731 and the Qing Empire once again faced the danger of losing control of Mongolia. A Khalkha ally of the Qing Empire would finally defeat the Dzungars a year later in 1732 near the Erdene Zuu Monastery in Mongolia. The Qing then made peace with the Dzungar Khanate and decided the border between them. The Han Chinese General Yue Zhongqi  conquered Tibet for the Qing during the Dzungar-Qing War and attacked the Dzungars at Urumqi in Xinjiang. The Oirats were battled against by Yue Zhongqi. Yue Zhongqi lived at the Ji Xiaolan Residence. Jalangga, a Manchu Bannermen, succeeded the Han General Yue Zhongqi as commander in 1732.
Question: How many years after Yongzheng Emperor sent an army of 230000 led by Nian Gengyao to an uprising in Qinghai did the Qing Empire face danger again of losing control of Mongolia?
Answer: 8