CEMENTING MIXTURES

摘要

A process for producing improved cementing mixtures by adding coal materials thereto. Low carbon content coal materials are crushed and screened to produce coal materials having a maximum diameter of 3/8 of an inch then exposed to a number of wetting and drying cycles, followed by a thorough leaching to remove water soluble and adhering substances therefrom, and produce therefrom a cleansed coal material. The cleansed coal materials are separated into first, second and third portions. In a first embodiment, an improved cementing mixture is produced by adding cleansed coal-material containing therein the requisite cement-making chemical ingredients, and fuel energy content sufficient to effect its own calcination, to a cement making kiln mixture in substitution for the raw material clays or shales normally used therewith. The cleansed coal material first portion so added, is made in a proportion of at least 60% coal material to 40% non-coal material portions of the mixture. In a second embodiment the second portion being soft burned utilizing its own fuel energy source at approximately 600.degree.F. such calcination being made prior to being added to the cement making kiln. This calcination provides a second or double cleansing of the coal materials thereby providing a double-cleansed and pre-calcined improved cement making additive, thus effecting a considerable saving in fuel energy consumption, more pure chemical ingredients and greatly improved cement production. In a third embodiment the third portion cleansed coal material is calcined in the same manner as in the second embodiment except that the temperature of calcination is raised to from 800.degree.F. to 2000.degree.F. and the calcined materials are converted thereby into highly active improved pozzolanic cementing mixtures after grinding to produce fine particulate material fillers and larger sized aggregate material. Surplus heated gases are drawn off for recycling of heat and re-util-ization of chemicals therein.