Studies were conducted to evaluate the Merrill–Crowe cementation method for the simultaneous extraction of platinum, palladium and gold associated with copper and nickel from cyanide solutions, particularly high temperature eluates from carbon adsorption and desorption process. The paper reviews the Merrill–Crowe method and its potential …
Its purpose was to examine the role that some selected parameters play in understanding and optimizing the conditions favouring the simultaneous 2. PT precipitation of Pt(II), Pd(II) and Au(I) on zinc particles. THE MERRILL-CROWE PROCESS CE The Merrill-Crowe process is a cementation process involving classic redox reactions.
Vacuum degassing is done in a packed tower. The clarified pregnant solution is introduced into the top of the tower and percolated down through the packing. Zinc Dust Addition. Zinc feeders are the nemesis of the Merrill-Crowe operators. The angle or repose of zinc dust is in excess of 90 degrees, it will "rat hole" and bridge.
Abstract. This paper is a brief overview of the role of inducing the nucleated precipitation of copper and cyanide in a flashtube serpentine reactor, using sodium sulfide as the precipitate and sulfuric acid as pH control. The results showed that pH had a great effect on copper cyanide removal efficiency and the optimum pH was about 3 to 3.5.
The clarified pregnant solution is introduced into the top of the tower and percolated down through the packing. Personal experience has shown that 6.75×10 4 Pa (20 inches Hg) gauge vacuum is sufficient for effective precipitation at 1500 m (5000 feet) MSL. Zinc feeders are the nemesis of the Merrill-Crowe operators.
The Operation of a Merrill-Crowe Zinc Precipitation circuit requires for Preparation for its Startup that the following items be checked before the equipment. ... Deaeration Crowe Tower. The deaeration tower is run under high vacuum. The deaerator feed pump should be running to give a slight excess of feed to the deaeration tower so …
The basic process was discovered and patented by Charles Washington Merrill around 1900, then later refined by Thomas B. Crowe, working for the Merrill Company. In more recent years the EMEW technology has started to replace this process through the use of electrowinning. See also. Other Gold cyanidation techniques: Carbon in pulp; …