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The companies are working cooperatively to increase the supply of lignosulfonates, which had been limited to about 65,000 tons per year. “With these upgrades, our plant is now capable of producing up to 95,000 tons lignin per year,” said Paul LaVanway, LignoTech president. The expansion allows Weyerhaeuser to increase the output of its pulping operation and allows LignoTech to grow and better meet the current and future demands for its lignosulfonate products.
Adding New EquipmentThe capital improvement project included four major components: a pressure filter, a vapor recompression evaporator, process controls, and new storage tanks and miscellaneous equipment. The new Larox pressure filter is capable of reducing the level of product insolubles from 3% to less than 0.1%. On a typical 100-ton shipment, that’s a difference of nearly 6,000 pounds. This improvement can also make unloading easier and more efficient for LignoTech’s customers.
The new vapor recompression evaporator is capable of removing up to 4 million pounds of water per day, an 82% increase over the previous equipment. Improved and more extensive PLC-based, multipoint computer process controls work to improve production efficiency and product quality. Finally, five new storage tanks, expanded loading facilities and other associated equipment also have increased the plant’s capabilities.
It was LignoTech’s desire to support the local economy by selecting Wisconsin-based vendors as much as possible. In the end, nearly 75% of the equipment and services for the project were sourced from Wisconsin companies.
What is Lignin?Lignin, which accounts for roughly one-third of the dry weight of a tree, occurs naturally in wood and quite literally holds a tree together; it is present in the cell walls and intercellular spaces of all woody plants. The pulping process chemically separates lignin from the cellulosic components used to manufacture paper. The lignin is then further processed and modified for a wide variety of industrial applications. Lignin is used extensively as both a binder and dispersant in numerous ceramic applications, including structural, refractory and technical ceramics manufacturing.
The world’s first investigations into the commercial development and application of lignin were conducted in Rothschild by Marathon Corp. The company started in 1909 with the commencement of the Rothschild pulp and paper operations near Wausau, Wis. In its early years, Marathon followed the practice common in the industry of discharging spent pulping liquids directly into the rivers. However, in 1927, long before any public or government pressure for clean air or water, Marathon assigned a group of chemists and engineers to the task of developing commercial products from the organic solids in the spent sulfite pulping liquor.
The first products to show promise were leather tanning agents. Later, characteristics of lignin as outstanding dispersing agents and binders became evident. By the mid-1930s, with much of the research accomplished, Marathon transferred operations from a research pilot plant to full scale production.
The lignin business grew and prospered, and changed hands several times. Following those early days as Marathon Corp., subsequent owners included American Can, Reed Lignin and Diashowa Chemicals.
LignoTech USA TodayIn 1991, the Norwegian company Borregaard acquired Daishowa’s U.S. lignin business and created the present company, LignoTech USA. Today, Borregaard LignoTech operates U.S. lignin plants in both Rothschild, Wis., and Mt. Vernon, Wa., as well as at 12 other plants around the world from Europe to South Africa to China. This scope allows LignoTech to operate as a truly global company, offering the most diverse and specialized product line of any lignin company in the world. In all, the company manufactures in excess of 300 different lignin products.
In the ceramic industry, LignoTech USA is best known for its line of Additive-A® clay conditioners used primarily in face brick manufacturing to reduce operating costs and increase strength and recovery. “We continue to be pleased to see our Additive-A® products delivering great value to our customers,” says Mike Schoenherr, business manager, general products. “As more and more brick manufacturers are required to use lower grade, less plastic clays in their brick-making operations, we believe demand for Additive-A®’s unique benefits will continue to increase.”
The Additive-A® products were originally developed by Kimberly-Clark Corp. in Wisconsin. LignoTech purchased this business in the mid-1970s and has continued to support its growth worldwide through research, technical support and ceramic specialists in the field.
With worldwide demand expected to continue to increase, the Rothschild plant upgrade allows LignoTech to grow to meet the future demand for its lignin products. Since LignoTech’s products are all derived from wood, they are considered more environmentally friendly than synthetic or petroleum-based products. This desirable attribute has resulted in increased demand for use in areas such as industrial and road dust control and as binders in agglomerating fine particles of limestone, fertilizer and a wide range of substrates where recycling is required or desired.
“This plant expansion is the latest evolution in the long and innovative history of this company,” LaVanway said. “In the 1920s we conducted the world’s first investigations into commercial development and applications of lignin. We’ve since changed ownership several times, but we’ve never lost our focus on research and development. Our chemists and chemical engineers are constantly looking for new and improved lignin chemical applications that will benefit our current and prospective customers.”