The main sources of impurity steel grit are as follows: the graphite nest is caused by frequent and excessive use of graphite; the quartz rod (and crucible, acid) is not used separately, and several metals are stirred with the same quartz rod; Foreign impurities, like nails, accidentally fall into the nest during the gold dissolution process and cause steel grit. The appearance of nickel steel grit in the inverted mold is also a common phenomenon of many companies. It mainly occurs in K white, which contains high nickel. The nickel is not completely dissolved in nickel. Nickel is a high-temperature metal with a melting point of 1453. Nickel is completely dissolved, and the principle of metal heat transfer needs to be used to accelerate the dissolution of nickel with low-temperature metals.
The reason is that the steel grit is not completely dissolved. In the process of dissolution, some high-temperature metals have not reached the temperature it should have, resulting in the steel grit that was not completely dissolved. The solution is to increase the temperature of the dissolving gold and the dissolving time for a longer time. There is also a chance that steel sands appear. Is there a separate type of bubble acid? For example, (white nickel) K white cannot be used in the same bucket as K yellow and K red, and K white must be separated. Nickel and silver will blame at a certain ratio, just like water drain oil. When molten gold, silver will cover nickel, so that nickel cannot be completely mixed with other metals to form a single metal-nickel.
During acid leaching, copper, nickel, silver and other metals will be slightly soluble in the acid, and nickel or silver in the acid may adhere to the golden tree, causing cross infection, immersion in K red and then immersion in K yellow. the reason. The old tree head is constantly used, and when these metal elements accumulate to a certain amount, nickel steel grit will be formed.