Saturday, July 22, 2017

What can we do for Effluent waste collected from ceramic industry

Ceramics industry uses a large quantities of water for various activities like raw materials mixing and grinding, slip production, washing, etc.

After processes like the above, a large quantity of water is collected as waste water which should be treated before reuse of released to the environment.
Therefore, a ceramic factory is always equipped with an Effluent Treatment Plant which process the waste water and produce clean water. The process also create a solid sludge extracted from the waste water. After a sedimentation and a filter pressing process, the sediments are collected as lumps, which some may use the name "ETP Cake".

The ETP sludge consists of a mix of raw materials used in the process like, clay, feldspar, silica, calcite, fits, color stains, etc.

There should be a proper waste management method to the above waste as some of the contents are some kind of hazardous to the environment. 

In most cases, the collected ETP cake is added back to the body in small quantities. But is some cases, this cannot be done as per the purity levels which should be maintained in the body formulations and firing variations/abnormalities due to mixture of raw materials. (eg: low melting raw materials mixed in the sludge which may create issues when firing to higher temperatures in a separate process)

Other than that, there are some occasions where the sludge from one ceramic process used as a raw materials for some other ceramic related production process. (eg: sludge from ceramic tiles/tableware manufacturing can be used for roof tiles manufacturing as a partial raw material as the purity required by the roof tiles are less and the firing conditions are lower.)

Though the best solution is to reduce the waste as much as possible, the waste water generation cannot be eliminated in some cases in the industry. So, more productive and reliable solutions should be facilitated.

People are looking in to other possibilities which the waste can be reduced and how the waste can be reused / recycled. 

Effect of water quality in the Ceramic Industry

We use a massive amount of water during the production process of Ceramic Products. (Am specially referring to Ceramics tiles manufacturing)
So, does the quality of water affect to the final quality of the product?

Water is mainly used for,
  1. Body Preparation
  2. Glaze/Engobe Preparation
  3. Washing of machinery
As per the production process and the usage, the quality of water will not affect to any quality parameter during the process of body preparation as almost all the water will be removed during spray drying (powder production) and as all the materials are soil related. 

But what about Engobe / Glaze preparation? 
Glaze is the top most layer of the tile and it is the part which exposed to the environment and the end user. the Glaze is a sensitive layer to firing temperature, oxygen amount when firing takes place, the soaking time, any materials to be evaporated through the glaze, etc.
So, the glaze could be affected by all above parameters and could have an impact to the final surface quality of the fired product's surface.

Glazes are produced using mainly non-reactive metal alkoxides (called as "Frits"), processed clay/Kaolin, Zirconium Dioxide, Naphalene, Corundum, other required additives and water.
the grinding process is done with water inside ball mills. 
The used water maybe drawn from mainly industrial wells / tube wells with underground water. Some industries use filters to filter the water and some are not. Filters will remove any particles from the water including, mud particles, some iron particles, some mineral particles, etc. But the water will not be totally purified. The soluble salts would be present in the filtered water also. 

What are soluble salts?
This term  refers to all those carbonates,  sulphates and alkaline/alkaline-earth chlorides soluble in water. This capacity varies enormously from mineral to mineral: values are sometimes so low (in the order of just a few parts per thousand) that they are, to all intents and purposes, insoluble.

The most important soluble salts are:
  • Ca, Mg, Na, K and Al sulphates
  • Na-Al, K-Al double sulphates
  • Ca, Na and K carbonates
  • Na and K chlorides.
Among these, calcium carbonate  (its definition as a soluble  salt considered by some to be improper) is present in all the clays used to produce porous bodies. 

Solubility of salts in water
Solubility (g/l)
CaS04 . 2H20

Back to the Topic
As you can see, the highest solubility is with Chlorides. But it is known that, chlorides for some extent, does not effect to any quality problems, But excessive amount of chlorides will cause problems in the operational stage. (eg: the glazes may tend to thicken/agglomerate due to high amount of chlorides, etc) 

The amount of soluble salts in the water used is found to affect the final surface quality of the glaze of the ware. (Sanitary, tableware, tiles)

The affects are occurred by 2 factors.

  • Ca++, Mg++ ions (which the water will be hard)
  • Sulphates in the water (SO4--)

Tests are being carried out to identify the effect of soluble salts to the final product quality of glazed ceramic tiles.  --

Wednesday, June 7, 2017

Quartz Industry in Sri Lanka

Quartz is an abundant mineral in the Earth's continental crust. It is a hard substance and can transmit ultraviolet light, unlike glass. Quartz is piezoelectric, which means that it creates a voltage when deformed. Quartz can produce a small electric charge by itself when it is put under pressure. So it is widely used in electronic industry.

Sri Lanka is famous throughout the world for the exquisite mineral varieties of very high purity. Among them vein quartz too holds prime importance. The material, generally known as quartz is primarily made of silicon and oxygen (silica-SiO2) and is considered one of the most abundant minerals found in the Earth's crust.

Major part of silica produced throughout the world is from silica sand. High purity silica sand is not so common; yet, high purity quartz is readily available in many areas of Sri Lanka. Most of these areas have reasonably large vein quartz deposits, (originated as veins) having very high purity (99.5 percent of SiO2).

Areas having abundant vein type quartz deposits
  • Pussella
  • Opanayake
  • Rattota
  • Naula
  • Galaha
  • Mahagama (Embilipitiya)
  • Wellawaya
  • High grade vein quartz can be used as a raw or refined material in many industries,

Uses of Quartz
  • Gem and jewelry
  • Lenses
  • Quartz-glass tubes for lamps
  • Sandpaper
  • Optics
  • Liquid filters
  • Solar panels
  • Semiconductor industry
  • Computer components
  • Ceramic ware manufacturing

Market conditions

In 2008 Sri Lanka exported its quartz to the German, Japanese, Malaysian, South Korean, Singaporean and more markets.

In 2008 Sri Lanka exported 37,109 metric tons (MTs) of quartz, that raked in Rs. 876.46 million (U.S. $ 7.6 million) in foreign exchange. The figure the previous year was 35,066 m.t.s. valued at Rs. 849.21 million (U.S. $ 7.4 million).
The government body, Geological Survey and Mines Bureau (G.S.M.B.), is the central body responsible for collating such data.
Though there is a ban in the export of quartz in lump form, this practice was allegedly continuing, with some of those exports being passed off as chips, an export that is however allowed.

Current Quartz producers/exporters in Sri Lanka
  • 3MB Aspire Quartz (Pvt) Limited
  • ALCHEMY Boulders (Pvt) Ltd
  • As-Shama (Pvt) Ltd
  • Blue Bay Mineral International Private Limited
  • Ceylon Industrial Minerals (Pvt) Ltd
  • Ceylon Minerals
  • Ceylon Quartz Industries (Pvt) Ltd
  • Ceyquartz MBI (Pvt) Ltd
  • Imexma Minerals (Pvt) Limited
  • J. Lanka Quartz (Pvt) Limited
  • Krishna Mining Company Ceylon Ltd
  • Nippon Techno International Private Limited
  • Soul Mates Trading


Monday, November 21, 2016

What are the Inputs For Identification of Risks and Opportunities

As you are aware, the major thing in ISO 9001:2015 is "Risk Based Thinking" where you have to consider risks and opportunities related to your organization with regard to every aspects like socio, economic, political, technological, etc. This would be not only in macro scale but for micro scale at production lines. 

For do this, there are many types of tools available. 
The following methods can be used for determining the inputs for identification of risks and opportunities to the company. There can be many, but these would be the more frequently used ones.

Saturday, November 19, 2016