GB615489A - Improvements in integrated mica and method of making the same - Google Patents

Abstract

615,489. Mica. HEYMAN, M. D. June 20, 1946. No. 18610. [Class 70] Sheets of mica are prepared by splitting pieces of mica into thin laminae while immersed in a medium such as methyl alcohol or distilled water which prevents contamination of the surfaces, and forming the laminae into a stratified sheet while still immersed in the medium. The mica is fed from a hopper 10a to a screen 12a where loose pieces and dirt are removed and thence to a cleaner 13a comprising a rapidly-reciprocating rubber-faced plunger 36 and a metal-faced platen supported on a rubber block 34 through which pins 33 project, so that the mica is subjected to rapid compression and release and flexure to cause removal of stones and other foreign matter. After passing over a screen 14a, the mica is washed and dried and fed to a disintegrator 17a having a series of vertically-communicating chambers of diminishing size and of ellipsoidal shape. Jets are arranged in the walls, in staggered relationship on opposite sides, and act to drive the mica around the walls and to split it. The jets are preferably supplied with pulsating liquid under the control of pumps 19a. The mica gradually floats upward and is finally delivered to a flotation tank 61 where any remaining foreign matter is deposited in the sump 62 and any large pieces of mica fall into a sump 64 whence they are returned to the disintegrator 17a. The liquid carrying the mica flakes passes over a magnetic roll 22 which acts to remove iron-contaminated flakes and the remainder passes to rotating screens 23, 24 where the flakes are graded and separated from the liquid which is recirculated. The flakes are passed into rotating fine-mesh screens wherein they are formed into cylinders by centrifugal action. The cylinders are cut, flattened in a press 27, preferably by vacuum, in an extractor 28 and, if desired, impregnated in a tank 29 and ground on a surface finisher 30.