Bioactive material

Abstract

A process and apparatus for manufacture of biocide products are described. The biocide properties arise from the caustic calcined powder, from carbonates such as such as magnesite and dolomite, and from hydroxides such as brucite. The method of manufacture is based on the production of high surface area oxide particles using an indirectly heated counterflow reactors for specifically calcining the carbonates and the hydroxides without significant sintering. The biocide products may be a powder or a hydrated slurry. A hydrated slurry is preferred for agricultural applications as a spray. For aquaculture applications, the products have a preferred particle size distribution to impact the aquatic and benthic ecosystems, and a Ca/Mg ratio that promotes the growth of the cultivates species when applied as a powder or a slurry. For applications such as a marine paint, the powder product or the slurry product is mixed with various agents to form a setting coating, and is applied to the infrastructure that is otherwise subject to biofilm growth.

1 . A process for producing a biocide powder, comprising the steps of:
 a. selecting one or more carbonate compounds with a predetermined calcium/magnesium ratio;   b. grinding the carbonate compounds to produce a carbonate powder with a first predetermined particle size distribution;   c. selecting a magnesium hydroxide compound;   d. grinding the hydroxide compound to produce a hydroxide powder with a second particle size distribution;   e. calcining the carbonate powder in an externally heated counterflow flash calciner at a first temperature to produce a calcined mixture having a surface area sufficiently high enough to exhibit bioactivity;   f. calcining the hydroxide powder in an externally heated counterflow flash calciner at a second temperature to produce a calcined oxide with a surface area sufficiently high enough to exhibit bioactivity; and   g. blending the calcined mixture and the calcined oxide in a predetermined proportions.   
     
     
         2 . The process of  claim 1  further comprising the step of adding ground limestone, or lime or hydrated lime to the form the biocide powder. 
     
     
         3 . The process of  claim 1 , wherein the carbonate compounds comprising Magnesite and Dolomite. 
     
     
         4 . The process of  claim 3 , wherein the degree of calcination of the magnesium carbonate in the magnesite and dolomite is in the vicinity of 95% or more, and the degree of calcination of the calcium carbonate is in the vicinity of 5% or less. 
     
     
         5 . The process of  claim 1 , wherein the calcined mixture and calcined oxide comprises magnesium oxide (MgO). 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The process of  claim 5 , wherein the surface area of the oxide from the hydroxide powder is above 200 m 2 /gm of MgO, and preferably above 250 m 2 /gm of MgO and most preferably above 300 m 2 /gm of MgO. 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . The process of  claim 2 , wherein the proportion of limestone, lime or hydrated lime depends on the specification to achieve a desirable Ca/Mg ratio for the application and to achieve a desirable viscosity and stability of the slurry in conjunction with an amount of carboxylic acid added in the slurry production process. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . The process of  claim 1 , further comprising the step of:
 a. hydrating the biocide powder with water at or near the boiling point of water until the hydration is completed;   b. Applying a shear mixing, and   c. Adding a carboxylic acid or salt as the thinning agent,   in order to form a stable, readily thinned, slurry of the hydrated oxide with about 60% solids in the final product.   
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . The process of  claim 13 , wherein the carboxylic acid is acetic acid, and the carboxylic salt is magnesium or calcium acetate. 
     
     
         28 . The process of  claim 17 , wherein the slurry is mixed with one or more viscosity modifier and setting additives for manufacturing a coating to sewage pipes and manholes. 
     
     
         29 . A reaction apparatus for producing biocide powder or a chemical detoxifier powder or a catalyst support from a carbonate mineral, comprising:
 a. a grinder for carbonate compounds   b. a grinder for hydroxide compounds   c. an externally heated counter flow flash calciner that produces high surface area oxides from the ground carbonate;   d. an externally heated counter flow flash calciner that produces high surface area oxides from the ground hydroxide; and   e. a blender in which the calcined solid powders arc mixed together, and or with other ground solids for the production of a biocide powder.   
     
     
         30 . The reaction apparatus of  claim 29 , further comprising a hydration reaction vessel for the production of the slurry product having an inlet for the blended powder and a water inlet; and a shearing apparatus for shearing the reaction mixture; and a steam outlet for release of steam from the reaction vessel, such that in use the reaction is controlled by allowing heat of hydration to raise the temperature of the reaction mixture, allowing water to boil off from the reaction mixture as hydration proceeds, and removing steam via the steam outlet to remove excess heat and control reaction temperature at boiling point; and a means of quenching the slurry to below 60° C. and a means of cooling the slurry to ambient temperature; and a means of adding solid or liquid additives to the slurry. 
     
     
         31 . The reaction apparatus of  claim 29  further comprising a second reaction apparatus, wherein the second reaction apparatus is adapted to carrying out one or more steps of:
 sparging the powder or slurry with a gas adjuvent enhance bioactivity; 
 adding and mixing liquid adjuvent compounds to the powder or slurry to enhance bioactivity; 
 adding and mixing materials to the powder or slurry to make a biocidal coating product; or 
 adding and mixing materials to the powder or slurry to make a biocidal emulsion or foam. 
 
     
     
         32 . A chemical composition as a powder adapted for use as a biocide, wherein the composition comprises: a powder of micron scale calcined particles which are formed from a mixture of carbonate compounds and hydroxide compounds, and which have additives to boost the biocide impact wherein the particles have a porosity of greater than 0.5 and wherein the pore surface is largely composed of nano-crystalline structures. 
     
     
         33 . A chemical composition as a slurry adapted for use as a biocide, wherein the composition comprises a slurry produced by hydrating the powder of  claim 31  with additives that stabilise the slurry. 
     
     
         34 . A chemical composition as a coating material slurry adapted for use as a biocide, wherein the composition comprises a coating material produced by mixing the powder of  claim 31  with additives that set the material when applied to a surface. 
     
     
         35 . A chemical composition as a foam, spray or emulsion material slurry adapted for use as a biocide, biofilm inhibitor, or plant root repellant, wherein the composition comprises a foam, spray or emulsion material produced by mixing the powder of  claim 31  with additives that form a foam, spray or emulsion when processed. 
     
     
         36 . The reaction apparatus according to  claim 30 , wherein the means of quenching the slurry to below 60° C. is by transfer of the slurry to a cooled container. 
     
     
         37 . The reaction apparatus of  claim 31 , wherein the gas adjuvant is ozone. 
     
     
         38 . The reaction apparatus according to  claim 32 , wherein the additives to boost the biocide impact is ozone and/or hydrogen peroxide.