Is cyanide, an environmentally friendly gold leaching agent, toxic?

Non-toxic and environmentally friendly gold leaching agent is a cyanide-free gold extraction agent. Take the method of stone-sulfur mixture as an example. This method is a new cyanide-free gold extraction agent pioneered in China. Is lime or Ca(OH) the environmentally friendly gold leaching agent used? Synthetic with sulfur. The mixed method of stone and sulfur has the characteristics of cheap and easily available reagents, fast gold leaching rate, high leaching rate of refractory ores, strong adaptability, no toxicity and no pollution.